Fermenting Milks and Creams

chriswrightcycles

On the heels of the ChefSteps homemade yogurt recipe a few weeks back, I feel inspired to try fermenting different varieties of milk and cream at home. Right now I'm looking at McGee's chart on "Traditional Fresh Fermented Milks and Creams" in his book On Food and Cooking for guidelines on bacteria types and acid concentrations. The chart lists acidity level as a percentage (Yogurt 1%-4%, Buttermilk 0.8%-1.1%, etc). My question is, how do I determine the percentage of acidity in my fermenting milk product? I have a pH meter available, and if McGee's chart listed acidity as pH as opposed to percentage this would be a bit easier.

Suggestions?

-Chris

kh.anuj

Assuming that lactic acid is the dominant acid in yoghurt. Yoghurt with 0.9% acidity would technically be 2.41. But the observed pH is about 4.0-4.8. Thing is yoghurt contains amino acids, colloidal salts etc that make such calculations a little difficult to do. Just go by your sense of taste. Acidity isn't an input but rather an output here.