While an average peasant household often made do with firewood collected from the surrounding woodlands, the major kitchens of households had to cope with the logistics of daily providing at least two meals for several hundred people. Guidelines on how to prepare for a two-day banquet can be found in the cookbook "Du fait de cuisine" ("On cookery") written in 1420 in part to compete with the court of Burgundy by Maistre Chiquart, master chef of Amadeus VIII, Duke of Savoy. Chiquart recommends that the chief cook should have at hand at least 1,000 cartloads of "good, dry firewood" and a large "barnful" of coal. Food preservation methods were basically the same as had been used since antiquity, and did not change much until the invention of canning in the early 19th century. The most common and simplest method was to expose foodstuffs to heat or wind to remove moisture, thereby prolonging the durability if not the flavor of almost any type of food from cereals to meats; the drying of food worked by drastically reducing the activity of various water-dependent microorganisms that cause decay. In warm climates this was mostly achieved by leaving food out in the sun, and in the cooler northern climates by exposure to strong winds (especially common for the preparation of stockfish), or in warm ovens, cellars, attics, and at times even in living quarters. Subjecting food to a number of chemical processes such as smoking, salting, brining, conserving or fermenting also made it keep longer. Most of these methods had the advantage of shorter preparation times and of introducing new flavors. Smoking or salting meat of livestock butchered in autumn was a common household strategy to avoid having to feed more animals than necessary during the lean winter months. Butter tended to be heavily salted (5–10%) in order not to spoil. Vegetables, eggs or fish were also often pickled in tightly packed jars, containing brine and acidic liquids (lemon juice, verjuice or vinegar). Another method was to seal the food by cooking it in sugar or honey or fat, in which it was then stored. Microbial modification was also encouraged, however, by a number of methods; grains, fruit and grapes were turned into alcoholic drinks thus killing any pathogens, and milk was fermented and curdled into a multitude of cheeses or buttermilk. The majority of the European population before industrialization lived in rural communities or isolated farms and households.