Cider
Cider ( ) is an alcoholic beverage made from the fermented juice of apples. Cider is popular in the United Kingdom, especially in the West Country, and widely available. The UK has the world's highest per capita consumption, as well as its largest cider-producing companies. Cider is also popular in many Commonwealth countries, such as India, Canada, Australia, and New Zealand. Aside from the UK and its former colonies, cider is popular in other European countries including Ireland, Portugal (mainly in Minho and Madeira), France (particularly Brittany and Normandy), northern Italy (Piedmont and Friuli), and Spain (especially Asturias and the Basque Country). Central Europe also has its own types of cider with Rhineland-Palatinate and Hesse producing a particularly tart version known as Apfelwein. In the U.S. and parts of Canada, varieties of fermented cider are often called "hard cider" to distinguish alcoholic cider from non-alcoholic "cider" or "sweet cider", also made from apples.
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.