Cider Vinegar comes from cider. The sugar in apple pulp is converted to alcohol and then to acetic acid. Cider vinegar is used a great deal for cooking and is a good substitute for rice vinegar in Chinese and Japanese cooking. Cider vinegar makes a good salad dressing.
Dowell, P., Bailey, A. (1980) The Book of Ingredients, Dorling Kindersley. ISBN 0718119150.