Cooking requires applying heat to a food which usually, though not always, chemically changes the molecules, thus changing its flavor, texture, appearance, and nutritional properties. Cooking certain proteins, such as egg whites, meats, and fish, denatures the protein, causing it to firm. There is archaeological evidence of roasted foodstuffs at Homo erectus campsites dating from 420,000 years ago. Boiling as a means of cooking requires a container, and has been practiced at least since the 10th millennium BC with the introduction of pottery.
The ideal temperature for serving a particular wine is a matter of debate by wine enthusiasts and sommeliers, but some broad guidelines have emerged that will generally enhance the experience of tasting certain common wines. A white wine should foster a sense of coolness, achieved by serving at "cellar temperature" (13 °C (55 °F)). Light red wines drunk young should also be brought to the table at this temperature, where they will quickly rise a few degrees. Red wines are generally perceived best when served chambré ("at room temperature"). However, this does not mean the temperature of the dining room—often around 21 °C (70 °F)—but rather the coolest room in the house and, therefore, always slightly cooler than the dining room itself. Pinot noir should be brought to the table for serving at 16 °C (61 °F) and will reach its full bouquet at 18 °C (64 °F). Cabernet Sauvignon, zinfandel, and Rhone varieties should be served at 18 °C (64 °F) and allowed to warm on the table to 21 °C (70 °F) for best aroma.
Phylogenetic analysis suggests that human ancestors may have invented cooking as far back as 1.8 million to 2.3 million years ago. Re-analysis of burnt bone fragments and plant ashes from the Wonderwerk Cave, South Africa, has provided evidence supporting control of fire by early humans there by 1 million years ago. There is evidence that Homo erectus was cooking their food as early as 500,000 years ago. Evidence for the controlled use of fire by Homo erectus beginning some 400,000 years ago has wide scholarly support. Archaeological evidence from 300,000 years ago, in the form of ancient hearths, earth ovens, burnt animal bones, and flint, are found across Europe and the Middle East. Anthropologists think that widespread cooking fires began about 250,000 years ago, when hearths started appearing.
^ Tomé-Carneiro, J; Gonzálvez, M; Larrosa, M; Yáñez-Gascón, MJ; García-Almagro, FJ; Ruiz-Ros, JA; Tomás-Barberán, FA; García-Conesa, MT; Espín, JC (July 2013). "Resveratrol in primary and secondary prevention of cardiovascular disease: a dietary and clinical perspective". Annals of the New York Academy of Sciences. 1290: 37–51. doi:10.1111/nyas.12150. PMID 23855464.
Freezing food preserves it from the time it is prepared to the time it is eaten. Since early times, farmers, fishermen, and trappers have preserved grains and produce in unheated buildings during the winter season. Freezing food slows down decomposition by turning residual moisture into ice, inhibiting the growth of most bacterial species. In the food commodity industry, there are two processes: mechanical and cryogenic (or flash freezing). The freezing kinetics is important to preserve the food quality and texture. Quicker freezing generates smaller ice crystals and maintains cellular structure. Cryogenic freezing is the quickest freezing technology available due to the ultra low liquid nitrogen temperature −196 °C (−320 °F).
Some foods not from animal or plant sources include various edible fungi, especially mushrooms. Fungi and ambient bacteria are used in the preparation of fermented and pickled foods like leavened bread, alcoholic drinks, cheese, pickles, kombucha, and yogurt. Another example is blue-green algae such as Spirulina. Inorganic substances such as salt, baking soda and cream of tartar are used to preserve or chemically alter an ingredient.