Reader Question: How is yogurt made?

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Question
An anonymous six-year-old child of a reader asks: How is yogurt made?

If you look carefully, you can see an ear, nose, and beard in the Rorschach ink blot.
(Photo: Wikimedia)

Summary (for an average six-year-old)
(Based on: Peanut Butter and Jelly)
First you take the milk and you heat it. (You heat it.)
Then you take the milk and you cool it. (You cool it.)
Then you take the bacteria and you add it. (You add it.)
Then it gets fermented. (Fermented.)
For your yogurt... white yogurt... and berries.

Explanation (for a smarter six-year-old)
Yogurt is based on the Turkish words for knead and thick although in some regions (e.g., Bulgaria) it is more like sour milk (which ambiguously refers to both milk that has soured and buttermilk).

The bacteria used in the fermentation process are Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus salivarius subsp. thermophilus which convert the lactose into lactic acid (which is what builds up on your muscles when you exercise, but doesn't degrade performance as previously thought).

Aside from the that the first summary captures the essence of the process.

See Also

• Yogurt at Wikipedia for more information.
• On Yogurt and Jiu-Jitsu at Hulu for a discussion of the relationship between yogurt and spying.