Soy milk (also called soya milk, soymilk, soybean milk, or soy juice) and sometimes referred to as soy drink/beverage is a beverage made from soybeans. A stable emulsion of oil, water, and protein, it is produced by soaking dry soybeans and grinding them with water. Soy milk contains about the same proportion of protein as cow's milk: around 3.5%; also 2% fat, 2.9% carbohydrate, and 0.5% ash. Soy milk can be made at home with traditional kitchen tools or with a soy milk machine.
The coagulated protein from soy milk can be made into tofu, just as dairy milk can be made into cheese.
The oldest evidence of soy milk production is from China where a kitchen scene proving use of soy milk is incised on a stone slab dated around A.D. 25–220. It also appeared in a chapter called Four Taboos (Szu-Hui) in the A.D. 82 book called Lunheng by Wang Chong, possibly the first written record of soy milk. Evidence of soy milk is rare prior to the 20th century and widespread usage before then is unlikely.
The drink is slowly becoming popular in India as well. Soy has originally been introduced by Mahatma Gandhi in 1935. Nowadays, it is also widely sold in Tetrapaks by various brands like Staeta.
Soy milk is promoted as a healthy alternative to cow's milk for reasons including:
- Source of lecithin and vitamin E
- Lacks casein
- It is safe for people with lactose intolerance or milk allergy
- Contains far less saturated fat than cow's milk.
- Contains isoflavones, organic chemicals that may possibly be beneficial to health.