Mechanism of Yogurt production: Three main things are happening here: Fermentation of milk by lactobacilli (special microorganisms that eat the milk sugar lactose), milk proteins are denatured by heating but will eventually get denatured even further and coagulate by the lactic acid produced by the microorganisms. Special bacteria called lactobacilli utilize milk sugar, and lactose as an energy source and produce lactic acid. The lactobacilli will also consume milk proteins, amino acids, etc., producing other flavor molecules in the yogurt. The lactic acid will change the pH of the milk, making it acidic, and the milk proteins will change their shape, and even the electric charges on the milk proteins will change. As a result, the milk proteins will split into a solid white cake-like structure, and some will remain soluble in the greenish whey liquid. Whey gets its green color from one of the B family’s vitamins, riboflavin. Heating the milk before the yogurt is added also helps to change protein structure through protein denaturation and will eventually lead to a better texture once the protein has coagulated. Making yogurt at home is not intimidating. You need to make sure you heat the milk to the right temperature. Read my notes before you start. 3 to 4 Tbsp of yogurt with LIVE cultures (see notes)
