Alcoholic cider, or hard cider, is produced by fermenting apple juice. The juice comes from a combination of cider and eating apples. The apples are scratted to produce a pulp and then layered in a block, separated by sweet straw. These layers are known as cheeses. Each block of pulp is then pressed to squeeze out the juice within. The juice is then poured into casks and allowed to ferment. Fermentation will often happen of its own accord, driven by the wild yeast present in the apples, but many commercial manufacturers will add champagne yeast to ensure a consistent product. Cider ferments slowly, typically at temperatures between 40 and 60 degrees Fahrenheit. Cider is typically ready to drink after three months, although fermentation will often last two or three years. Ciders can be sweet or dry, sparkling or still. The characteristics of cider vary substantially, depending on in which country and with what ingredients it is made.