Cookware and bakeware
Cookware and bakeware is food preparation equipment, such as cooking pots, pans, baking sheets etc. used in kitchens. Cookware is used on a stove or range cooktop, while bakeware is used in an oven. Some utensils are considered both cookware and bakeware.
There is a great variety of cookware and bakeware in shape, material, and inside surface. Some materials conduct heat well; some retain heat well. Some surfaces are non-stick; some require seasoning.
Some pots and their lids have handles or knobs made of low thermal conductance materials such as bakelite, plastic or wood, which make them easy to pick up without oven gloves.
A good cooking pot design has an "overcook edge" which is what the lid lies on. The lid has a dripping edge that prevents condensation fluid from dripping off when handling the lid or putting it down.
History
The history of cooking vessels before the development of pottery is minimal due to the limited archaeological evidence. The earliest pottery vessels, dating from, were discovered in Xianrendong Cave, Jiangxi, China. The pottery may have been used as cookware, manufactured by hunter-gatherers. It is also possible to extrapolate likely developments based on methods used by latter peoples. Among the first of the techniques believed to be used by Stone Age civilizations were improvements to basic roasting. In addition to exposing food to direct heat from either an open fire or hot embers, it is possible to cover the food with clay or large leaves before roasting to preserve moisture in the cooked result. Examples of similar techniques are still in use in many modern cuisines.Of greater difficulty was finding a method to boil water. For people without access to natural heated water sources, such as hot springs, heated stones could be placed in a water-filled vessel to raise its temperature. In many locations the shells of turtles or large mollusks provided a source for waterproof cooking vessels. Bamboo tubes sealed at the end with clay provided a usable container in Asia, while the inhabitants of the Tehuacan Valley began carving large stone bowls that were permanently set into a hearth as early as 7,000 BC.
According to Frank Hamilton Cushing, Native American cooking baskets used by the Zuni developed from mesh casings woven to stabilize gourd water vessels. He reported witnessing cooking basket use by Havasupai in 1881. Roasting baskets covered with clay would be filled with wood coals and the product to be roasted. When the thus-fired clay separated from the basket, it would become a usable clay roasting pan in itself. This indicates a steady progression from use of woven gourd casings to waterproof cooking baskets to pottery. Other than in many other cultures, Native Americans used and still use the heat source inside the cookware. Cooking baskets are filled with hot stones and roasting pans with wood coals. Native Americans would form a basket from large leaves to boil water, according to historical novelist Louis L'Amour. As long as the flames did not reach above the level of water in the basket, the leaves would not burn through.
The development of pottery allowed for the creation of fireproof cooking vessels in a variety of shapes and sizes. Coating the earthenware with some type of plant gum, and later glazes, converted the porous container into a waterproof vessel. The earthenware cookware could then be suspended over a fire through use of a tripod or other apparatus, or even be placed directly into a low fire or coal bed as in the case of the pipkin. Ceramics conduct heat poorly, however, so ceramic pots must cook over relatively low heats and over long periods of time. However, most ceramic pots will crack if used on the stovetop, and are only intended for the oven.
The development of bronze and iron metalworking skills allowed for cookware made from metal to be manufactured, although adoption of the new cookware was slow due to the much higher cost. After the development of metal cookware there was little new development in cookware, with the standard Medieval kitchen utilizing a cauldron and a shallow earthenware pan for most cooking tasks, with a spit employed for roasting.
By the 17th century, it was common for a Western kitchen to contain a number of skillets, baking pans, a kettle and several pots, along with a variety of pot hooks and trivets. Brass or copper vessels were common in Asia and Europe, whilst iron pots were common in the American colonies. Improvements in metallurgy during the 19th and 20th centuries allowed for pots and pans from metals such as steel, stainless steel and aluminium to be economically produced.
Cookware materials
Metal
Metal pots are made from a narrow range of metals because pots and pans need to conduct heat well, but also need to be chemically unreactive so that they do not alter the flavor of the food. Most materials that are conductive enough to heat evenly are too reactive to use in food preparation. In some cases, a pot may be made out of a more reactive metal, and then tinned or clad with another. While metal pots take heat very well, they usually react poorly to rapid cooling, such as being plunged into water while hot, this will usually warp the piece over time.Aluminium
Aluminium is a lightweight metal with very good thermal conductivity. It is resistant to many forms of corrosion. Aluminium is commonly available in sheet, cast, or anodized forms, and may be physically combined with other metals.Sheet aluminium is spun or stamped into form. Due to the softness of the metal, it may be alloyed with magnesium, copper, or bronze to increase its strength. Sheet aluminium is commonly used for baking sheets, pie plates, and cake or muffin pans. Deep or shallow pots may be formed from sheet aluminium.
Cast aluminium can produce a thicker product than sheet aluminium, and is appropriate for irregular shapes and thicknesses. Due to the microscopic pores caused by the casting process, cast aluminium has a lower thermal conductivity than sheet aluminium. It is also more expensive. Accordingly, cast aluminium cookware has become less common. It is used, for example, to make Dutch ovens lightweight and bundt pans heavy duty, and used in ladles and handles and woks to keep the sides at a lower temperature than the center.
Anodized aluminium has had the naturally occurring layer of aluminium oxide thickened by an electrolytic process to create a surface that is hard and non-reactive. It is used for sauté pans, stockpots, roasters, and Dutch ovens.
Uncoated and un-anodized aluminium can react with acidic foods to change the taste of the food. Sauces containing egg yolks, or vegetables such as asparagus or artichokes may cause oxidation of non-anodized aluminium.
Aluminium exposure has been suggested as a risk factor for Alzheimer's disease. Of one of which its proponents is Prof. Christopher Exley, who has published his findings. However, the Alzheimer's Association states that "studies have failed to confirm any role for aluminum in causing Alzheimer's." The link remains controversial.
Copper
provides the highest thermal conductivity among non-noble metals and is therefore fast heating with unparalleled heat distribution . Pots and pans are cold-formed from copper sheets of various thicknesses, with those in excess of 2.5 mm considered commercial grade. Between 1 mm and 2.5 mm wall thickness is considered utility grade, with thicknesses below 1.5 mm often requiring tube beading or edge rolling for reinforcement. Less than 1mm wall thickness is generally considered decorative, with exception made for the case of.75–1 mm planished copper, which is hardened by hammering and therefore expresses performance and strength characteristic of thicker material.Copper thickness of less than.25 mm is, in the case of cookware, referred to as foil and must be formed to a more structurally rigid metal to produce a serviceable vessel. Such applications of copper are purely aesthetic and do not materially contribute to cookware performance.
Copper is reactive with acidic foods which can result in corrosion, the byproducts of which can foment copper toxicity. In certain circumstances, however, unlined copper is recommended and safe, for instance in the preparation of meringue, where copper ions prompt proteins to denature and enable stronger protein bonds across the sulfur contained in egg whites. Unlined copper is also used in the making of preserves, jams and jellies. Copper does not store heat, and so thermal flows reverse almost immediately upon removal from heat. This allows precise control of consistency and texture while cooking sugar and pectin-thickened preparations. Alone, fruit acid would be sufficient to cause leaching of copper byproducts, but naturally occurring fruit sugars and added preserving sugars buffer copper reactivity. Unlined pans have thereby been used safely in such applications for centuries.
Lining copper pots and pans prevents copper from contact with acidic foods. The most popular lining types are tin, stainless steel, nickel and silver.
The use of tin dates back many centuries and is the original lining for copper cookware. Although the patent for canning in sheet tin was secured in 1810 in England, legendary French chef Auguste Escoffier experimented with a solution for provisioning the French army while in the field by adapting the tin lining techniques used for his cookware to more robust steel containers which protected the cans from corrosion and soldiers from lead solder and botulism poisoning.
Tin linings sufficiently robust for cooking are wiped onto copper by hand, producing a 35–45 µm thick lining. Decorative copper cookware, i.e., a pot or pan less than 1 mm thick and therefore unsuited to cooking, will often be electroplate lined with tin. Should a wiped tin lining be damaged or wear out the cookware can be re-tinned, usually for much less cost than the purchase price of the pan. Tin presents a smooth crystalline structure and is therefore relatively non-stick in cooking applications. As a relatively soft metal abrasive cleansers or cleaning techniques can accelerate wear of tin linings. Wood, silicone or plastic implements are to preferred over harder stainless steel types.
For a period following the Second World War, copper cookware was electroplated with a nickel lining. Nickel is harder and more thermally efficient than tin, with a higher melting point. Despite its hardness, it wore out as fast as tin, as the plating was 20 microns thick or less, as nickel tends to plate somewhat irregularly, and requires milling to produce an even cooking surface. Nickel is also stickier than tin or silver. Copper cookware with aged or damaged nickel linings can be retinned, or possibly replating with nickel, although this is no longer widely available. Nickel linings began to fall out of favor in the 1980s owing to the isolation of nickel as an allergen.
Silver is also applied to copper by means of electroplating, and provides an interior finish that is at once smooth, more durable than either tin or nickel, relatively non-stick and extremely thermally efficient. Copper and silver bond extremely well owing to their shared high electro-conductivity. Lining thickness varies widely by maker, but averages between 7 and 10 microns. The disadvantages of silver are expense and the tendency of sulfurous foods, especially brassicas, to discolor. Worn silver linings on copper cookware can be restored by stripping and re-electroplating.
Copper cookware lined with a thin layer of stainless steel is available from most modern European manufacturers. Stainless steel is 25 times less thermally conductive than copper, and is sometimes critiqued for compromising the efficacy of the copper with which it is bonded. Among the advantages of stainless steel are its durability and corrosion resistance, and although relatively sticky and subject to food residue adhesions, stainless steel is tolerant of most abrasive cleaning techniques and metal implements. Stainless steel forms a pan's structural element when bonded to copper and is irreparable in the event of wear or damage.
Using modern metal bonding techniques, such as cladding, copper is frequently incorporated into cookware constructed of primarily dissimilar metal, such as stainless steel, often as an enclosed diffusion layer.