Cider
Cider is an ancient beverage. No-one knows when or where it was first made, because the native distribution of its principal component, the apple, is so widespread, from the Near East to Northwestern Europe. In the cider market, ciders can be broken down into two main styles, standard and specialty. The first group consists of modern ciders and heritage ciders. Modern ciders are produced from culinary apples such as Gala. Heritage ciders are produced from heritage, cider specific, crab or wild apples, like Golden Russet. Historically, cider was made from the only resources available to make it, so style wasn't a large factor when considering the production process. Apples were historically confined to the cooler climates of Western Europe and Britain where civilization was slow to develop record keeping. Cider was first made from crab apples, ancestors of the bittersweet and bittersharp apples used by today's English cider makers.
Cider
An important component in cider-making is the addition of sulphur dioxide to inhibit the growth of many spoilage bacteria or yeasts in the juice. This encourages the inoculated yeast to dominate the juice environment, converting sugars to alcohol. Once sulfur dioxide dissolves in the juice, it converts into a pH dependent mixture of bisulfite, sulfite ions, and molecular sulfur dioxide. The "unbound" sulfur dioxide provides the antimicrobial environment in the juice, while the bisulfite and sulfite ions contribute to flavor. The quantity of sulfur dioxide needed to inhibit microbial activity is directed related to pH of the juice; lower pH means less should be added, while higher pH juice requires more. Many cider producers add sulfur dioxide immediately after pressing and juicing, but before fermentation. However, in some cases it can be added afterwards to act as an antioxidant or stabilizer. This prevents the finished cider from releasing hydrogen peroxide or aldehydes that produce "off" odors and flavors.