Tart is Smart

White Mountain Foods | October 19th, 2016

Q: What does the beneficial bacteria do to the milk to make yogurt?

A: Beneficial bacteria basically pre-digest the milk for us making it much easier for our digestive tracts to absorb the milk’s nutrients. When the bacteria are introduced to the warm milk they do what any other living thing does: feed, multiply and produce by-products. The bacteria feed on the milk sugar (lactose) converting it to lactic acid (producing the tartness of naturally fermented yogurt), thereby making the milk accessible to those that have a hard time digesting lactose. The lactic acid helps break down milk proteins and other nutrients, making them easier to digest – in addition to providing an astringent preservative effect on the body after consumption.

The rapidly multiplying bacteria cause the milk to thicken due to their sheer numbers and through the formation of strands of living bacteria that do not fully separate from each other during the multiplication process. This stranding effect produces most of the thickness of the finished yogurt, much like adding conditioner to your hair produces a “fuller” look. Once the yogurt has begun to thicken, the temperature must be lowered to slow down the bacteria. If allowed to continue unchecked the bacteria would use up all the lactose and die leaving highly acidic curds and whey.  Timing and temperature control are very important aspects of making traditional yogurt.