The diversity of the range of metal utensils is created by different sizes of products, shape and design of handles, type of side, design of lids, and decorative design of products. The main dimensions of metal utensils are provided for by GOSTs. The handles on the body and lid of the cookware can be flat stamped, round cast or hollow. By design, handles can be fixed, movable or removable. The side of metal utensils can be edged, protected by a stainless steel rim, and rolled. The design of the covers can be overhead, side, or inset. The most common types of decorative finishing are decal, stencil, continuous and downward covering, engraving.
Enameled steel cookware. It accounts for more than 65% of the production of metal utensils. It is used for thermal processing of food products, table setting and other purposes.
Thick-walled steel enameled cookware with a thickened bottom has the best consumer properties. Having a significantly higher heat capacity, the bottom of such cookware serves as a kind of “thermal damper” between the heat source and the food being prepared. We have mastered the production of cookware with a special mechanical treatment of the bottom for better contact with the surface of heating devices, bimetal cookware with Teflon coating, with thinned (inset) lids that prevent liquid from splashing out during boiling, with a stainless steel rim edging the sides and edges of the lid to prevent chipping enamels.
To finish enameled steel cookware, tinting, finishing with colored stripes, downward coating, brushing, silk screen printing, stenciling, hand painting, and decal are used.
Galvanized steel utensils. It is used mainly for economic purposes. Its range is not wide and includes the following types of products: tanks for washing clothes, basins, bathtubs, troughs, buckets for short-term storage of cold water, cans for kerosene, watering cans, funnels for pouring fuels and lubricants. The dishes are made sewn or solidly stamped, with a wall thickness of 0.35 to 0.70 mm. The rigidity of the products is ensured by rolling wire into the side, as well as by making stiffening ribs, which are usually located along the entire circumference on the walls of the product. To seal the seams of products, soldering with tin-lead solder is used.
As a result of anodic oxidation, zinc coatings can be painted in various colors: purple, dark blue, green, yellow and red.
Tinned steel cookware. The range of tinned dishes is also small: milk buckets, milkers, flasks for transporting milk, strainers, funnels, jars for storing bulk products. Tin coating is resistant to water, organic acids, and environmental influences. It does not change the taste properties of food products and does not destroy vitamins. These properties of the coating determine the intended purpose of tinned cookware. The main disadvantage of tinned steel cookware is rapid corrosion if the integrity of the tin coating is damaged.
Cookware made of corrosion-resistant steel. Such utensils have a number of advantages: high chemical resistance to food environments at normal and elevated temperatures, hygiene, durability during use, and attractive appearance. However, due to low thermal conductivity, food burns in it, so it is unsuitable for frying and baking. In this regard, dishes made of corrosion-resistant steel with a heat-distributing layer on the bottom are increasingly used. It has significant advantages over cookware made from other materials.
The range of types of stainless steel cookware includes more than 20 items: containers, colanders, portioned frying pans, dishes, ladles, plates, strainers, rams, vessels, bowls, etc.
The range of stainless steel tableware includes bowls, butter dishes, gravy boats, cezves, menazhniki, cocotte makers, chillers, etc.
Chillers - plates in the form of a round shell with a small handle at the base - are used for serving shrimp, crayfish, and oysters.
Cocotte makers - cylinder-shaped products with a long handle - are used for serving oven-baked meat, mushrooms, and vegetables.
Cream bowls are vases designed for serving cream and ice cream.
Lambs are round and oval plates with a high lid, designed for serving hot meat, fish and vegetable dishes.
Menazhnitsa - plates with partitions for various types of salads.
Dishes made of aluminum alloys. For its production, aluminum alloys of grades AD1, AD, A7, A6, bimetallic sheets of aluminum grade A7T1 and steel grade St7, etc. are used. The product range includes pots, pans, coffee pots, teapots, basins, bowls, plates, etc. The range is expanding over the years due to the production of products of different shapes and sizes, the design and material of handles, types of coatings and methods of surface finishing and other factors.
To finish dishes, various types of coatings are used: etching, polishing, chemical staining, anodizing, enameling, nickel plating, chrome plating, stainless steel plating, enameling with silicate enamels, painting with paints and varnishes, etc. Various mechanical methods of surface texture are used.
Dishes with improved consumer properties. In recent years, the production of cookware of improved quality has been organized in the country and abroad: with non-stick coating, from multilayer materials, etc.
Cookware with a non-stick coating has high consumer properties, which is due to the unique set of properties of the Teflon coating (domestic analogue - fluoroplastic) applied to the inner surface of the products. Thanks to these properties, food does not burn, it retains a greater amount of substances beneficial to humans, and fats are saved. The procedure for washing dishes is also simplified.
Non-stick cookware is made from aluminum and steel. The production of such utensils based on the bimetal aluminum - steel - aluminum has been organized.
Utensils made from multilayer materials containing one or more heat-conducting layers, as well as from corrosion-resistant steel with a heat-distributing bottom, are increasingly used.
Based on the composition of the metal, cookware is distinguished between aluminum, enameled, and stainless steel.
Tableware is made from various types of enameled metal. Household utensils made of stainless steel and enameled, increasing chemical and thermal resistance; kitchen made of special aluminum and cast iron.
There are about thirty types of tableware: forks, spoons, table knives, sugar bowls, butter dishes, vases for table setting (for fruit, jam, cookies, cream, sweets, salad bowls), cocotte bowls, chilli bowls, etc.
Decorative items include metal sculptures, flower vases, toiletries, horn-shaped glasses, dishes, etc.
Each type of product is produced in several varieties (articles), differing in size and style.
By size, dishes are divided into small, medium, large, and extra large. The size of products is characterized by diameter, length or height, and the size of hollow products is characterized by capacity.
By style, products are subdivided taking into account the shape of the body (ball, oval, cone, etc.), the presence of stick-on (handle, leg, lid holder) and removable (cork, lid) parts, the nature of the edge (smooth, cut-out) and the bottom of the products. The dishes are produced with a bottom of regular thickness, thickened, and also on a pallet (a protrusion or ledge at the bottom of the product).
Materials used for the manufacture of inventory, equipment, dishes, packaging. Hygienic requirements for materials. Advantages and disadvantages of polymer materials.
Theoretical lesson No. 17.
Question 8. Investment process in Russia and its structural features
A study of the investment behavior of basic subjects of the Russian economy allows us to draw the following conclusions.
One of the trends in recent years is the continuation of intensive growth of investments in fixed capital (Fig. 14.14).
At the same time, the high intensity of the investment process masks a sharp increase in sectoral differentiation of investments.
Structural features of the investment process are manifested in the following:
1. Investment breakthrough in the communications industry;
2. Accelerating the modernization of production in the primary industries;
3. Maintaining high dynamics of investment in the housing sector;
4. Stopping the growth of investment in manufacturing industries;
5. Reducing the role of borrowings by companies in foreign markets and replacing them with their own funds and bank loans.
Rice. 14.14. Investments in fixed assets
(billion rubles, in comparable 2003 prices.)
Source: materials of the Center for Macroeconomic Analysis and Short-Term Forecasting.
Despite certain positive changes in the investment process, it is extremely important to note a number of other catalysts for economic growth. Thus, Russia's GDP in the period 1999-2005. increased by an average of 6.7% annually, based on high oil prices, a “weak” ruble, growth in production and the service sector. Stable economic growth in recent years has become possible primarily due to high oil prices in combination with structural reforms carried out by the Russian Government in 2000-2001.
GDP growth has caused increased confidence among business circles and ordinary consumers in a more favorable economic future for Russia, as a result of which the influx of foreign investment into the economy has significantly increased and the outflow of capital from the country has practically stopped.
Materials approved by the Ministry of Health of the Republic of Belarus for contact with food are used.
Food utensils, equipment coverings, and containers are made from various materials: glass, metals, wood, paper, cardboard, clay, mineral raw materials, and various polymer materials.
Hygienic requirements for materials:
Should not contain harmful substances that pass into food;
Should not have a negative impact on the biological value of the product, not deteriorate the organoleptic properties of products or finished food;
Must ensure the protection of food products from environmental contamination;
Must have a smooth, polished, non-porous inner surface.
Characteristics of base materials:
Metal utensils. Metals are widely used for the manufacture of kitchen and tableware, pipelines in the food industry, cutlery, containers for transporting liquid products, washing baths, etc.
Stainless steel of some food brands has high anti-corrosion properties and resistance to aggressive food environments. Stainless steel products are highly durable and durable in use.
Aluminum cookware. Aluminum, duralumin and their alloys are used as materials for making cookware. Aluminum and its compounds have poor solubility in liquid aggressive food media. Aluminum cookware, especially those made from alloys, are susceptible to the effects of table salt and some organic acids contained in vegetables, fruits, and berries. In this case, the protective film of aluminum oxides, which protects the dishes from corrosion, dissolves in the liquid contents. In this regard, it is not recommended to ferment cabbage, pickle cucumbers, cook sour cabbage soup, etc. in aluminum cookware. To increase the anti-corrosion properties of aluminum cookware, modern processing methods are used - the inner surface is ground, polished, varnished, made matte silver, etc. Aluminum alloys are used to produce foil, which is widely used in the confectionery industry; varnished foil is used for packaging cheeses. Aluminum alloys contain impurities of certain metals that can have a harmful effect on the human body; therefore, the impurities used are strictly standardized (zinc, lead, arsenic, copper, iron).
Utensils made of iron and cast iron. Iron is a common material for the manufacture of digesters, containers, equipment, buckets, frying pans, baking sheets, and enamelware. Iron is not stable and is easily susceptible to oxidation and the formation of compounds that dissolve in liquid food, causing changes in its color (darkening) and taste (metallic taste). For this reason, iron products must have protective coatings. Only baking sheets and frying pans are used without coatings, on which food is cooked in the presence of fat (fat, by covering the surface of the iron, prevents the oxidizing effect of oxygen). For iron utensils, coatings made of enamel, tin (tinning), and zinc (galvanized utensils) are used.
Enameled dishes. It is an iron dish, the outer and inner sides of which are covered with enamel - an alloy (like glass) of feldspar, soda, borax, sand, tin oxide. Strict requirements are imposed on the preparation of enamels, especially those intended for interior coatings, since if the recipe is violated, compounds that cause food poisoning (lead, antimony, etc.) can be used as components. Enameled cookware is not often used in public catering and retail establishments, as it has poor impact resistance and heat resistance - with a sharp change in temperature and impact, cracks and chips form, exposing the iron. It is prohibited to use dishes with chips for cooking and storing food.
Ceramic tableware. Ceramic ware includes clay, glazed (pottery), earthenware, and porcelain ware.
Glazed earthenware. Pottery is not widely used at present. To make them, clay baked in a kiln is used. Glaze is applied to the inside and outside of the dishes - an alloy of oxides of silicon, potassium, sodium and other metals, as well as lead oxide (lightweight). For coating pottery, a special grade of fritted glaze with a lead content of about 12% should be used. The fritted glaze is highly durable and does not contain easily soluble lead compounds. At industrial enterprises producing enameled and pottery ware, local sanitary and epidemiological service authorities must conduct strict control over the quality of enamels and glazes.
Earthenware and porcelain dishes. It is a clay product that differs somewhat in chemical composition and manufacturing technology. The outside and inside of the product are covered with glaze. The glaze of earthenware products, which contains lead (to add shine), is not particularly durable. When using the product, a network of small cracks appears and chips easily form. The use of such utensils is not permitted.
Glassware. Glass is used to make glasses, wine glasses, jars, bottles and other products for contact with food. Glass must be highly resistant to acids contained in products. There are special brands of heat-resistant glass that are used to make pots and pans used in everyday life. Impact-resistant and acid-resistant glass is used for the manufacture of pipelines in dairies, wineries and other food industrial enterprises.
If the manufacturing technology is violated, air bubbles may appear in the thickness of the glass, which reduces the strength of the glass and increases the possibility of it getting into food products. If there are many bubbles, the dishes are rejected. If chips appear along the top edge, glass products must be rejected. Glassware made from glass with foreign inclusions is not allowed to be used, as they reduce the durability of the products.
Wooden utensils, containers, equipment. Wood is widely used for the manufacture of cutting boards, small equipment (stirrers, rolling pins), barrels, kegs, blocks for cutting meat and fish, etc. Wood does not have a harmful effect on the quality of products, does not change their organoleptic and physico-chemical properties, does not corrode and does not release harmful substances into the food mass. At the same time, wood is porous, absorbs liquid substances, and can be subject to bacterial attack (mucus-forming bacteria, mold, etc.). In order to reduce or eliminate the ability to absorb liquid substances, wood products are impregnated or coated from the inside with varnishes or resins approved for contact with food. For the same purpose, the inside of wood products is lined with liner bags made of synthetic materials.
Wooden containers are used for storing pickled and salted vegetables and mushrooms, salted fish and corned beef, tomato paste and other products.
Paper containers and packaging. Paper sheets are used as packaging material for solid food products. Disposable paper tableware (waxed ice cream and sour cream cups, plates, etc.) is made from paper pulp impregnated with approved grades of paraffin. High-grade paper (parchment and sub-parchment) is used for packaging fat-containing products - butter, cheese, herring, waffles, etc. This paper does not absorb moisture and fat and prevents products from drying out. Paper is increasingly used in combination with synthetic materials.
It is worth saying that for writing inscriptions and drawings on paper, paint is used that is approved for use by the State Sanitary Inspection authorities. Paints should not leave an imprint on the surface of the product (curd cheese) or give it an extraneous odor. The use of such paints should not be allowed. The use of paints containing soluble toxic substances is also not permitted.
Cardboard and corrugated cardboard are used for packaging confectionery products. Cardboard and corrugated cardboard are used for packaging wrapped products. To package confectionery products without wrappers, the inside of cardboard boxes must be glued or lined with parchment or sub-parchment. Today, a combination of cardboard and synthetic materials is used.
The range of metal utensils is quite wide and is divided according to a number of characteristics.
Purpose. There are utensils for thermal processing of food products (cooking, stewing, frying), for preparing cold dishes and serving the table, for storing and carrying food products, sanitary and hygienic and auxiliary.
Type of metal. For the manufacture of metal utensils, gray cast iron, low-carbon steel sheets, thin-sheet corrosion-resistant steel, aluminum alloys (duralumin, silumin), copper alloys (brass, cupronickel, nickel silver) are used.
Method of manufacturing products and connecting parts. Depending on the type of metal or alloy, the production of tableware is carried out by casting, stamping, stitching, pressing, drawing, rotary drawing with the subsequent attachment of fittings (handles, ears, spouts) using electric spot welding, riveting, soldering, etc.
Type of coverage. Depending on the type of alloy used for the manufacture of dishes and its purpose, metal protective and decorative coatings are used (zinc plating, tinning, chrome plating, nickel plating, gold plating, silver plating, titanium plating) and non-metallic (enamelling, enamelling, dyeing, varnishing, oxidation, bluing , blackening, anodizing, coating with grease and polymer compounds).
The nature of finishing and decoration of products. Surface treatment is carried out with the aim of leveling it, improving hygienic and aesthetic properties, and increasing decorativeness. Based on this feature, the dishes can have a ground, polished, brushed, etched surface, etc.
To improve the appearance, decorating the surface of the dishes by rolling corrugations is used; embossing (manual or mechanical); filigree (filigree) in the form of an openwork pattern made from thin copper, silver or gold wires; engraving (a design in the form of narrow indentations forming a pattern and obtained by cutting with special cutters). Various surface texture methods are also used.
Completeness. On this basis, tableware is divided into pieceware and complete in the form of sets, cutlery and services. Complete products are distinguished by a uniform style design and finishing, general purpose, and are becoming increasingly widespread due to steady consumer demand.
Dimensional sign provides for the division of dishes by capacity (l) for hollow products and linear dimensions (mm) for flat ones.
Types of products. The range of utensils for the thermal processing of food products includes the following types of products: saucepans, ducklings, cauldrons, cauldrons, pots, frying pans, fish bowls, baking trays, baking dishes, teapots, tanks for sterilization for home canning.
The range of utensils for cooking, table setting and serving includes dishes, plates, bowls, mugs, vases for bread, fruit, cakes, gravy boats, crackers, buckets for cooling champagne, cream jugs, milk jugs, coffee pots, coquettes, cocotte makers, cheese bowls , bowls, butter dishes, coffee makers, sugar bowls, cup holders, rams, portion pans, trays, colanders, ladles, etc.
The range of utensils for storing and carrying food products includes cans, buckets, water cans, and containers.
Sanitary and hygienic and auxiliary utensils include products for washing clothes, bathing, storing and carrying non-food products, etc. (canisters, tanks, basins, bathtubs, troughs, chamber pots, kerosene cans, funnels, etc.).
Product form. Metal utensils can be cylindrical, conical, spherical, rectangular, complex, or a combination of these shapes.
The diversity of the range of metal utensils is created by different sizes of products, shape and design of handles, type of side, design of lids, and decorative design of products. The main dimensions of metal utensils are provided for by GOSTs. The handles on the body and lid of the cookware can be flat stamped, round cast or hollow. By design, handles can be fixed, movable or removable. The side of metal utensils can be edged, protected by a stainless steel rim, and rolled. The design of the covers can be overhead, side, or inset. The most common types of decorative finishing are decal, stencil, continuous and downward covering, engraving.
Enameled steel cookware. It accounts for more than 65% of the production of metal utensils. It is used for thermal processing of food products, table setting and other purposes.
Thick-walled steel enameled cookware with a thickened bottom has the best consumer properties. Having a significantly higher heat capacity, the bottom of such cookware serves as a kind of “thermal damper” between the heat source and the food being prepared. We have mastered the production of cookware with a special mechanical treatment of the bottom for better contact with the surface of heating devices, bimetal cookware with Teflon coating, with thinned (inset) lids that prevent liquid from splashing out during boiling, with a stainless steel rim edging the sides and edges of the lid to prevent chipping enamels.
To finish enameled steel cookware, tinting, finishing with colored stripes, downward coating, brushing, silk screen printing, stenciling, hand painting, and decal are used.
Galvanized steel utensils. It is used mainly for economic purposes. Its range is not wide and includes the following types of products: tanks for washing clothes, basins, bathtubs, troughs, buckets for short-term storage of cold water, cans for kerosene, watering cans, funnels for pouring fuels and lubricants. The dishes are made sewn or solidly stamped, with a wall thickness of 0.35 to 0.70 mm. The rigidity of the products is ensured by rolling wire into the side, as well as by making stiffening ribs, which are usually located along the entire circumference on the walls of the product. To seal the seams of products, soldering with tin-lead solder is used.
As a result of anodic oxidation, zinc coatings can be painted in various colors: purple, dark blue, green, yellow and red.
Tinned steel cookware. The range of tinned dishes is also small: milk buckets, milkers, flasks for transporting milk, strainers, funnels, jars for storing bulk products. Tin coating is resistant to water, organic acids, and environmental influences. It does not change the taste properties of food products and does not destroy vitamins. These properties of the coating determine the intended purpose of tinned cookware. The main disadvantage of tinned steel cookware is rapid corrosion if the integrity of the tin coating is damaged.
Stainless steel cookware. Such utensils have a number of advantages: high chemical resistance to food environments at normal and elevated temperatures, hygiene, durability during use, and attractive appearance. However, due to low thermal conductivity, food burns in it, so it is unsuitable for frying and baking. In this regard, stainless steel cookware with a heat distribution layer on the bottom is increasingly used. It has significant advantages over cookware made from other materials.
The range of types of stainless steel cookware includes more than 20 items: containers, colanders, portioned frying pans, dishes, ladles, plates, strainers, rams, vessels, bowls, etc.
The range of stainless steel tableware includes chillers, cocotte makers, bowls, rams, menazhniki, etc.
Kokilnitsy- plates in the form of a round shell with a small handle at the base - used for serving shrimp, crayfish, oysters.
Cocotte makers- cylinder-shaped products with a long handle - used for serving oven-baked meat, mushrooms, and vegetables.
Kremanki- vases intended for serving cream and ice cream.
Rams- round and oval plates with a high lid, designed for serving hot meat, fish and vegetable dishes.
Menazhnitsy- plates with partitions for various types of salads.
Aluminum cookware. For its production, aluminum alloys of grades AD1, AD, A7, A6, bimetallic sheets of aluminum grade AD1 and steel grade St7, etc. are used. The product range includes pots, pans, coffee pots, teapots, basins, bowls, plates, etc. The range is expanding over the years due to the production of products of different shapes and sizes, the design and material of handles, types of coatings and methods of surface finishing and other factors.
To finish dishes, various types of coatings are used: etching, polishing, chemical staining, anodizing, enameling, nickel plating, chrome plating, stainless steel plating, enameling with silicate enamels, painting with paints and varnishes, etc. Various mechanical methods of surface texture are used.
Due to its amphoteric properties, aluminum can react with food products and partially pass into food, accumulating in it and negatively affecting human health. Therefore, despite the lightness, cheapness and other advantages of aluminum cookware, it is still in limited demand, especially abroad.
Cookware made of copper alloys. Its assortment includes items for table setting. These are gravy boats, cream jugs, milk jugs, vases, sugar bowls, glass holders, coffee makers, coffee pots, teapots, etc.
Products made from cupronickel and nickel silver are coated with silver or gold, and those made from brass are coated with chrome and nickel; Chemical and electrochemical staining and blackening are used.
Utensils made of copper alloys intended for food purposes must be coated inside with tin, which prevents copper and zinc ions, which are toxic to the human body, from entering food (drinks).
Cupronickel and nickel silver dishes are marked (respectively “MN” or “melch” and “MNC”).
Cast iron cookware. Used for cooking, frying, stewing food. The range includes the following types: saucepans, ducklings, cauldrons, cauldrons, pots, frying pans, etc. Cast iron cookware is produced black (without coating), with one-sided and double-sided enamel coating.
Cast iron cookware is heat-resistant, durable, and convenient for preparing various dishes. Its disadvantage is its large mass and low aesthetic properties. Black cast iron cookware somewhat changes the taste properties of food and is used to a limited extent.
Dishes with improved consumer properties. In recent years, the production of cookware of improved quality has been organized in the country and abroad: with non-stick coating, from multilayer materials, etc.
Cookware with a non-stick coating has high consumer properties, which is due to the unique set of properties of the Teflon coating (domestic analogue - fluoroplastic) applied to the inner surface of the products. Thanks to these properties, food does not burn, it retains a greater amount of substances beneficial to humans, and fats are saved. The procedure for washing dishes is also simplified.
Non-stick cookware is made from aluminum and steel. The production of such utensils based on the bimetal aluminum - steel - aluminum has been organized.
Utensils made from multilayer materials containing one or more heat-conducting layers, as well as from corrosion-resistant steel with a heat-distributing bottom, are increasingly used.
Metal utensils are classified into utensils for food and non-food purposes.
According to their intended purpose, food utensils are divided into:
kitchen,
Dining room,
For storing and transporting food.
Kitchen utensils are used for cooking food and storing food at home. Tableware is intended for setting the table and serving food to the table.
Non-food utensils include products for storing, carrying non-food products, cleaning, washing, washing, sanitary and hygienic and other household purposes.
Depending on the metal, manufacturing method and type of protective and decorative coating, dishes are divided into:
Cast iron (black and enameled);
Steel (enamelled, galvanized, tinned, painted, black);
Made of corrosion-resistant (stainless) steel;
Aluminum (sheet and cast);
Made from copper-based alloys.
In subgroups, metal utensils are divided into types and varieties.
Cast iron cookware.
Cast iron cookware has been around for a long time; it is made by casting gray cast iron. Black cast iron cookware has low thermal conductivity. Thanks to the thick walls and bottom of the cookware, the food in it is evenly heated and almost does not burn, so it is used mainly for frying and stewing food. This was the main advantage of using it. Black cast iron cookware has significant disadvantages: black color, large mass, low corrosion resistance, surface roughness. For these reasons, black cast iron cookware is used to a limited extent.
The usual black cast iron cookware was replaced by enameled cast iron cookware. It has higher functional, hygienic and aesthetic properties compared to black cast iron cookware due to the silicate enamel coating (except for the bottom). Products of an improved design are covered with external bright enamels, additionally decorated (contrasting or background) with a stencil, covering, decals, and hand painting.
Copper utensils
Copper has the highest thermal conductivity of all materials suitable for making cookware.
Some houses still have copper basins with a long handle, in which it was customary to make jam. It never burns in a copper basin due to the fact that the heat spreads quickly and evenly across the entire bottom, without forming hot spots.
If you use copper utensils that are not cleaned of oxides, they interact with acids and alkalis, which are the majority of food products. Copper alloys often used are brass (copper plus zinc), bronze (alloys of copper with various elements, mainly tin, aluminum, beryllium, lead, cadmium and others) and copper-nickel alloys, including cupronickel and nickel silver. These alloys acquire new properties compared to pure copper (corrosion resistance, hardness), but none of them can compare with it in thermal conductivity. Today, copper and brass utensils are most often used to find cezves, or so-called Turks for brewing coffee. To avoid the harmful effects of copper oxides, the Turks tin the inside (cover with a layer of food-grade tin). In fact, copper, bronze and brass are now also used in cookware, but in combination with stainless steel, giving steel the qualities it lacks.
Aluminum cookware.
For many years, aluminum cookware suited most people. It is light, durable, and then this dishware was very cheap. And the main positive quality is that aluminum is a good conductor of heat; water boils in such a pan quite quickly.
The thermal conductivity of the materials from which kitchen utensils are made is a very important indicator by which we will compare different utensils. Therefore, I will immediately present here a comparison of the thermal conductivity of different materials.
Only copper is better than aluminum in terms of thermal conductivity. In the old days, most kitchen utensils were indeed made from copper, especially since aluminum was unknown. Due to the fact that aluminum turned out to be much cheaper than copper, aluminum cookware has become very common. Aluminum cookware is usually thin-walled and made by stamping. This also makes its price very affordable.
But besides these advantages, the other qualities of aluminum are complete disadvantages. Firstly, this metal is too soft. Pots, pans and lids made of pure aluminum are easily deformed. Therefore, aluminum alloys are used to make cookware, which make it harder, while thermal conductivity decreases, but remains quite high. Alloys may include magnesium, manganese, zinc... All these substances are by no means inert, and they are capable of reacting with food.
Aluminum has a protective oxide film that is easily dissolved by alkali solutions. And many food products have an alkaline reaction, for example, potatoes, green cabbage soup from sorrel, and many soups. Following this, the aluminum exposed from under the oxide film reacts, forming compounds that are not harmless to our health.
Although aluminum has become more expensive, it is still widely used today to make quality cookware. The trick is that it now works in combination with stainless steel, non-stick coatings. In modern cookware, contact of food with aluminum is not allowed, but its ability to quickly heat up and accumulate heat is successfully used.
Enameled cookware
For a long time, an alternative to aluminum was enamel cookware, which was more expensive. Now this is one of the cheapest types of kitchen utensils.
This is a massive, rather heavy cookware made of cast iron or black steel (density 7.6-7.86 g/cm3) on the surface of which a durable glassy enamel coating is applied in 2-3 layers. The smooth glassy surface is quite hygienic, it prevents the growth of bacteria, and the smell of food does not linger on the walls of the dishes. Modern enamel is very durable, resistant to salts, acids and alkalis found in food; any dishes can be prepared and stored in such utensils.
The enamel coating is selected so that its coefficient of thermal expansion is the same as that of a steel or cast iron base. Thanks to this, the enamel does not fly off when the cookware is heated on the stove or during slow cooling.
At first, only white enamel dishes were made. Dark enamel is now widespread. And even light-colored enamel pans now have a specially blackened bottom on the outside. Heating of such a pan over the fire will proceed somewhat faster. At the same time, according to Russian standards, enamel cookware can be any color on the outside, but only white on the inside. Also, enamel cookware is produced in sets, which is welcomed by consumers.
Steel utensils.
Enameled steel cookware has a complex of valuable functional, aesthetic and other consumer properties. Enameled steel cookware is made from thin sheet carbon steel 0.5-2.5 mm thick and covered with a protective and decorative layer of silicate enamel. The body of the cookware is made by stamping, products with a long body by drawing, handles by cutting, and large-sized products by stitching. Handles and spouts are attached to the body using electric spot welding. For handles, hardwood, plastic (aminoplastics), and ceramics are used.
The range of enameled steel cookware for cooking food products includes: pots of various shapes, including for electric stoves, teapots, coffee pots.
Enameled steel utensils for storing and transporting food include: buckets, cans, tanks, jars, trays, jugs, ladles.
The bottom of the dishes (pans, saucepans, saucepans) for the rational use of thermal energy has a 1-2 mm thick coating on the outside of highly thermally conductive metals (copper, bronze, brass, aluminum) or a specially thickened heat-distributing bottom. The process of cooking in dishes with such a heat-distributing bottom is significantly accelerated.
Galvanized steel utensils are used for storing and transporting cold water (buckets, tanks), for sanitary and hygienic purposes (basins, bathtubs, troughs, tanks), for fuels and lubricants (cans, funnels, buckets for kerosene and fuels and lubricants). Such utensils are made sewn or solidly stamped from galvanized sheet steel or from steel sheet followed by galvanizing. The thickness of steel for the manufacture of baths, tanks, troughs is 0.5-0.7 mm, for other products 0.35-0.55 mm. Galvanized cookware is characterized by high mechanical strength and good corrosion resistance. The zinc oxide film dissolves in weak solutions of acids, alkalis and hot water, forming toxic compounds. As a result, galvanized steel cookware should not be used for boiling drinking water or cooking food. The warning label “For non-food products” is required on the labeling of buckets and water tanks. For sanitary and hygienic purposes, round and oval basins, troughs, bathtubs, and tanks are used. The range of galvanized steel utensils has narrowed significantly in recent years, since sanitary and hygienic products are made mainly from plastics.
Tinned steel cookware. To make it, tinplate with a thickness of 0.36-0.45 mm or sheet carbon steel with a thickness of 0.4-5 mm is used, followed by coating the products outside and inside with a layer of tin. Tin must be at least 20 g/m2 of tinned surface. The consumer properties of tinned steel cookware are determined by the properties of tin. In everyday life, tinned dishes are used mainly for collecting and storing milk on private farms. Tinned buckets, milk bowls, tubs, strainers, funnels, and flasks with a sealed lid are intended for milk. Tin cans are suitable for storing bulk products, except salt.
Painted steel utensils are coated on one or both sides with enamel or oil paints. It is used very limitedly - for household and sanitary purposes: buckets and bins for garbage, water (non-potable), cans, mugs, funnels, garden watering cans, kerosene cans, tanks, barrels.
Cookware made of copper-nickel alloys.
The range of cookware made from copper-nickel alloys is represented by products made from brass, cupronickel, and nickel silver.
Brass is a toxic alloy, therefore the inner surface of this cookware is coated with tin, nickel or two layers of nickel and tin, the outer surface is coated with chromium or nickel or both nickel and chromium. Brass is used to produce tea and coffee products, for table setting, samovars (charcoal and electric), and bowls for making jam. The coating is not applied to the inner and outer surfaces of the cans, since sugar prevents the dissolution of copper and zinc during cooking.
For the internal coating, the same materials are used as for brass utensils, and the outside of the product, in addition, can be coated with silver, gold or alloys based on them. The range of tableware made from cupronickel and nickel silver includes coffee pots, teapots, sugar bowls, milk jugs, candy dishes, crackers, fruit vases, cake stands, trays, round dishes, oval dishes, bowls (for ice cream), cocotte makers, chillers for portioned hot snacks ( mushrooms, fish).
Stainless steel
Today stainless steel is called the “material of the century”, which is now widely used for kitchen utensils.
After all, scratches do not form on solid steel, as on aluminum or enamel cookware, where dirt would accumulate, providing a favorable environment for the proliferation of microbes.
Stainless steel cookware is more hygienic; it is highly resistant to acids and alkalis, including at high temperatures.
The only thing this dish doesn’t like is having strong brine in it for a long time. Spots may appear. The instructions that come with steel cookware do not even recommend putting salt in cold water. It is better to add salt to hot water while stirring so that the grains dissolve immediately. In addition, rainbow stains may form on the surface of stainless steel cookware, especially new ones, after use.
Stainless steel cookware always has a polished surface. Good dishes shine like a mirror, and it is not only beautiful, but also functional. According to the laws of physics, shiny surfaces cool much more slowly than matte ones. Therefore, food in stainless steel cookware stays hot longer.
Cheap types of dishes from Asia are sold only in markets. There is no guarantee for such cookware, and the service life is a maximum of 2-3 years. Cookware that meets the requirements of GOST has a warranty period of at least two years and the declared service life, as a rule, is at least 6 years. In fact, it lasts much longer.
Good stainless steel cookware is noticeably more expensive than enameled and even more so aluminum cookware. It is much more durable than cookware with a fluoropolymer non-stick coating. In a good “stainless steel” with a tight-fitting lid, you can cook without oil or water, and traces of food are washed off as easily as from cookware with a non-stick coating. The thin steel bottom begins to bend over time due to high temperature, the contact of the bottom with the flat electric burner is broken, and this is no longer a saucepan, but just a disappointment. It can't even stand stably on a flat burner, not to mention it has very poor heat transfer. We tried to solve this problem by making the bottom of pots and pans more massive. But it is simply impossible to avoid sudden changes in temperature and the formation of hot spots, and the food continues to burn.
Non-stick coatings
It was possible to improve the consumer qualities of the inner surface of aluminum cookware with the help of non-stick coatings. The most common fluoropolymer coating today (incorrectly called Teflon in everyday life) has been used for more than 50 years.
Cookware with a non-stick coating can be made of aluminum (stamped or cast) or steel, enameled on the outside. Moreover, aluminum does not exhibit the undesirable properties described above here, since it is covered with a durable inert layer of fluoropolymer.
This interesting polymer is a surprisingly inert material. It does not react with oxidizing agents, alkalis, acids, or organic solvents. Therefore, it does not react chemically with any food products, water or household detergents.
Another useful property of this material is that it has a smooth and slippery surface that experiences virtually no friction; nothing sticks to its surface. When in the 50s of the 20th century they tried to make non-stick coatings for frying pans from it, this cookware quickly conquered the whole world.
Manufacturers set the full service life for thin, cheap frying pans at 2-4 years, while frying pans with a more durable cellular coating last 5-6 years. The most durable are cast frying pans, which have a bottom thickness of at least 6 mm, walls of variable section 3.5 mm thick and a hardened rough coating or a new multi-layer one; they can last up to 10 years.
Crockery with double or triple bottom
Due to their low thermal conductivity, stainless steel cookware was not particularly successful. Finally figured out how to solve this problem. It is necessary to mount a disk of aluminum or copper with good thermal conductivity into the bottom of the steel cookware. In recent decades, the development of technology has made it possible to solve this problem.
First, dishes appeared with an aluminum disk welded (soldered) on the bottom. But since aluminum quickly loses its appearance, a more advanced design has appeared with a lower covering capsule made of stainless steel.
Nowadays, the so-called puff bottom, “sandwich” or encapsulated bottom is widely used in stainless steel cookware. This bottom is called thermal distribution: food does not burn, and the dishes retain heat for a long time.
A traditional “sandwich” is two sheets of stainless steel, between which layers of copper or aluminum are laid. Sometimes the walls of the dishes are also made multi-layered (this technology is called Tri-ply). In any case, food only comes into contact with hygienic stainless steel.
Now there is a very interesting question about the thickness of the layers in this “sandwich”. The thickness of the aluminum thermal distribution layer according to GOST 27002-86 must be at least three millimeters, and the thickness of copper at least 1.5 millimeters. From the point of view of the “consumer quality/price” criterion, the thickness of the aluminum layer is considered to be 4-5 mm. It is possible to make this layer thicker, but it is not necessary. Greater thickness only makes the dishes more expensive and heavier.
Lids, handles and other accessories. Lids. They can be made of the same metal as the pot or frying pan - either glass or a combination. For example, stainless steel kitchenware is now equipped with tight-fitting lids - made of the same stainless steel or heat-resistant glass. Clear glass lids allow you to see when soup is boiling, for example, to reduce heat. This is not only convenient, but also saves energy since each time you remove the lid, a fair amount of heat is released.
Pay attention to the fastening of the handle to the lid. It is advisable that there are no bolts, nuts or rivets on the back of the cover. Food particles can accumulate in these places and cannot be removed. In addition, such fasteners quickly corrode.
Thermal sensors. Manufacturers call a temperature sensor, or even a temperature controller, ordinary thermometers, laconically calibrated and installed on the lids of dishes. The circular scale of the temperature sensor is usually divided into three color sectors: yellow, green and red. Each sector shows a specific temperature range.
Of course, temperature sensors provide the necessary information about the degree of heating. They help ensure that the cooking mode is optimal. True, temperature sensors make dishes more expensive. At the same time, experience shows that they are not always structurally reliable.
metal utensils commodity consumer
Metal utensils are classified:
1. According to the material of manufacture:
Cast iron (heavy, brittle, heat-resistant, if uncoated - only for frying, because low corrosion resistance);
Steel (durable, strong, due to low thermal conductivity, food burns; enameled utensils made of carbon steel must be protected from shock);
Aluminum (lightweight, deforms upon impact, cannot be used for preparing salty, sour foods and those containing vitamin C);
Made from multilayer materials (for example: outer wall - aluminum, intermediate layer - copper, inner layer - alloy steel, heat up quickly, food does not burn, durable, beautiful appearance).
2. According to production method:
Stamped;
Stitched.
3. According to the form:
Conical;
Cylindrical;
Hemispherical;
Square.
4. By design:
With or without handle;
With or without lid;
With steel edge edging (protects the edges of the product from chipping the enamel);
With a thickened bottom (prevents food from burning).
5. By type of protective and decorative coating:
Enameled;
Galvanized;
Nickel plated;
Chrome plated;
Painted;
Polished, etc.
6. By purpose and type:
a) to ear – for cooking and hot drinks:
Pan (including juice cookers, pressure cookers, pressure cookers);
Frying pans;
Teapots;
Coffee pots;
Baking dishes;
c) with dining room- for setting the table and serving food to the table:
Dishes;
Oil cans;
Cream bowls;
Sugar bowls;
Jugs;
Cup holders;
c) d For storing and transporting food:
- buckets (enamel);
Cans for bulk products;
Thermoses (with a metal flask);
Tanks for drinking water, etc.
d) e For storing and transporting non-food products:
Buckets (galvanized, painted carbon steel);
Canisters;
Cans for kerosene;
Funnels, etc.;
e) and sanitary and hygienic products:
Boiling tanks;
Baby baths;
Night vases;
Washstands.
Quality control carried out in accordance with the normative and technical documentation. By external inspection the following is checked:
The shape of the product must be correct and stable on the surface;
Surface - must be smooth (uniform roughness is allowed for cast products), without cracks, burrs, sharp edges;
Protective and decorative coating - must be uniform over the entire surface, durable, without peeling, chipping, exposing the base metal, or swelling;
The fastening of the fittings is strong, without cracks;
The lids must fit tightly to the body;
The dishes must be waterproof;
Availability of markings;
Fit for purpose and performs required functions.
To maintain the quality of metal cookware, it is necessary to ensure proper storage- at a temperature of 12-18C, avoiding sharp fluctuations, because Condensation may remain, humidity 65-70%, protecting against water ingress, taking into account stacking conditions.
Questions for self-control:
1. What are the similarities and differences between cast iron and steel, aluminum and titanium, chromium and nickel.
2. Feature of cast iron, steel, aluminum cookware.
3. Feature of enameled, nickel-plated, galvanized cookware.
4. What production method can be used to make a cast iron duck pot, an enameled steel pan, or a galvanized steel bucket?
5. Which group of utensils are intended for food products?
6. List the quality indicators of metal utensils.
TOPIC 6. FURNITURE PRODUCTS
1. Classification and characteristics of materials used in furniture production.
2. Classification and characteristics of the furniture range. Quality requirements.
Classification and characteristics of materials,
Used in furniture production
Furniture products occupy a significant place in a person’s life, influencing his physiological and psychological state. By improving raw materials and the production cycle, furniture is also being improved, becoming more comfortable, easy to use and aesthetically pleasing.
Furniture materials significantly affect the consumer properties and quality of furniture.
Furniture materials are classified according to raw materials into:
Woody;
Metal;
Glass;
Polymer;
Textile, leather, etc.
Wood materials:
- boards– environmentally friendly natural material, the width is more than 2 times the thickness;
- bars- environmentally friendly natural material, width and thickness are approximately the same;
- particle boards (chipboards)) – wood particles in a phenol-formaldehyde resin binder, furniture is inexpensive, you can make everything except chairs and armchairs, it’s heavy, it swells from moisture; toxic - needs to be lined, loose edges crumble;
- fibreboard (fibreboard)– crushed wood and paper particles processed at high pressure and temperature with a mixture of phenol-formaldehyde resin and paraffin, dimensional stability, easy to machine, easily subject to various types of finishing, less toxic, limited use (mainly for drawers and bottoms);
- wood slabs– slatted panels glued on one or both sides with veneer (for doors, side walls, table tops);
- plywood– glued peeled veneer (from 3 to 13 sheets) with perpendicularly located fibers in adjacent sheets;
- furniture panels– frames filled with wood shavings or paper composition, lined on both sides with veneer or plywood (for doors, facade parts);
- veneer– thin sheets of wood (0.4 - 4 mm), intended for cladding surfaces made of chipboard, fiberboard, to eliminate the toxicity of materials and improve aesthetic properties.
Metal materials:
- supports, pipes(square or round) - for the supporting frame of legs, racks, increases the strength of the furniture, and hence the service life, saves wood;
- springs– for the production of elastic bases of upholstered furniture, they have high strength and elasticity.
Glass materials:
- glass sheets- polished, colored, tinted, patterned, for the manufacture of doors, shelves, improve the aesthetic properties of furniture, however, increase its fragility.
Polymer materials:
- laminates– replace natural veneer, surpassing it in strength and water resistance (for kitchen and office furniture);
- films– imitate various materials, incl. valuable types of wood, intended for decorative finishing of furniture;
- polypropylene, ABC plastic (impact-resistant polystyrene) – a structural material, a substitute for wood and metal load-bearing structures in furniture, for the manufacture of children's, office, and kitchen furniture. It has the following properties: lightweight, resistant to corrosion, abrasion, low cost, more hygienic than fiberboard, chipboard;
- foam rubber, latex, foam-PVC– for the production of elastic bases for upholstered furniture, the most common elastic materials, however, age over time, losing shape, strength and elasticity.
Textile, leather and other materials:
- fabrics(tapestry, flock, chenille, velor) - for upholstery of upholstered furniture, the most resistant to abrasion are flock and chenille;
- leather- for upholstery of upholstered furniture, natural (best abrasion resistance, expensive), artificial, synthetic;
- horsehair– elastic, ecological flooring material for upholstery of upholstered furniture, when tensioned it increases by 20-30%, when removed it returns to its original position;
- cotton wool (batting) – flooring, ecological, cheap material.
Classification and characteristics of the furniture range.
Quality requirements
Furniture products are classified:
By purpose:
Household;
For public buildings;
Children's room.
By completeness:
Piece;
Complete
According to design and technological characteristics:
Cabinet (panel) – for storing individual items;
Bar (carpentry) – chairs, tables;
Bent – parts are made by bending;
Wicker - parts are made of weaving (from willow or polymer tubes);
Soft – for sitting and lying;
Universal prefabricated - from standardized elements allows for the assembly of various options in shape and size;
Non-removable;
Built-in – in the building structure;
Transformable - sofa bed, chair bed;
Sectional – assembled from sections;
Mounted;
Foldable;
Combined.
By type of source material:
Wooden;
Metal;
Plastic;
Combined.
By type:
- carpentry furniture– chairs, work chairs;
- cabinet furniture– wardrobes (for dresses, linen, books, dishes), tables (dining tables, coffee tables, desks, shelves, dressing table, trellis, etc.);
- cushioned furniture– sofa, lounge chair, ottoman (with pillow), couch (without backrest), bed, banquette, etc.);
- kitchen furniture- stool, cabinets for household supplies and dishes, tables (cabinets, sinks, kitchen);
- hallway furniture– hangers, cabinets and cabinets for storing outerwear and shoes;
- bent furniture– chairs, stool, bent hangers;
- wicker furniture– chair, stool, table;
- headsets- sets of furniture products with a single design for furnishing one room;
- sets- sets of furniture with a uniform stylish design, the composition of which depends on the number of people and rooms.
Furniture quality determined on the basis of the requirements of the normative and technical documentation. Defects on furniture are checked using an organoleptic method. Some of them, depending on the type, size, location, are allowed with restrictions (fused knots, slope of fibers, eyes, curls) but no more than 3 pieces on one product. Rot, decayed knots, mold, and tar are not allowed. Roughness - no more than the standards established by GOST. Inadmissible cladding defects include: un-glued areas, wrinkles, stains, traces of glue, discrepancies and overlaps of cladding, coating defects (bubbles, scratches, smudges, peeling, cracks). During assembly, distortions, weak fastenings, and cracks are not allowed. In upholstered furniture, the flooring should be level.
Curvature of the seams, discrepancy between the color of the threads and the color of the materials, and wrinkles are not allowed, unless this is provided for in the technical documentation. All materials used for furniture production must be certified. When using furniture, substances harmful to humans should not be released. The manufacturer independently determines the service life of the goods (on average 10-15 years).
Questions for self-control:
1. What is the difference between fiberboard and chipboard?
2. Which furniture materials are physiologically harmless?
3. What is the purpose of horsehair in furniture production?
4. Features of panel board, carpentry, upholstery. Bent, wicker furniture.
5. List unacceptable furniture defects.
TOPIC 7. RANGE OF CONSTRUCTION PRODUCTS
1. Classification and characteristics of the range of mineral binders. Requirements for quality, labeling, packaging, storage.
2. Classification and characteristics of the range of roofing materials. Requirements for quality, labeling, packaging, storage.
3. Classification and characteristics of the range of materials for walls, partitions, and floors. Requirements for quality, labeling, packaging, storage.
4. Classification and characteristics of the range of facing and finishing materials. Requirements for quality, labeling, packaging, storage.
5. Classification and characteristics of the range of glazing materials. Requirements for quality, labeling, packaging, storage.
6. Classification and characteristics of the range of sanitary products Requirements for quality, labeling, packaging, storage.