Recipes

Soy Yogurt, Homemade

The one plant milk that genuinely sets on its own, and therefore the only non-dairy yogurt I would call a straight substitute rather than a workaround. Soy protein gels when acidified — the same chemistry that makes tofu — so you do not need starch, agar or gums. The catch is that soy milk has no lactose, so you have to feed the culture.

Fermented · Dairy Free

Soy Yogurt, Homemade
Prep 20 minutes
Cook 6–10 hours incubation
Serves Makes 1 quart
Level Easy

The one plant milk that genuinely sets on its own, and therefore the only non-dairy yogurt I would call a straight substitute rather than a workaround. Soy protein gels when acidified — the same chemistry that makes tofu — so you do not need starch, agar or gums. The catch is that soy milk has no lactose, so you have to feed the culture.

Ingredients

  • 1 quart plain unsweetened soy milk (soybeans and water only)
  • 4 tsp sugar or maple syrup
  • 2–3 Tbsp live plain yogurt, or a vegan yogurt starter

Directions

  1. Key ingredients
  2. Plain soy milk with the shortest possible ingredient list, sugar to feed the culture, and a starter.
  3. Buy the right milk — this decides the outcome. Soybeans and water, nothing else. No gums, no oils, no ‘barista’ formulation, and specifically NO ADDED CALCIUM CARBONATE, which buffers the acid and can stall the pH drop. Look for 7 g or more of protein per cup; protein content is the predictor.
  4. Add the sugar. This is not optional for most plant milks. The yogurt organisms eat milk sugar and soy milk has none they can readily use. The sugar gets consumed — the finished yogurt is not sweet.
  5. Heat to 180 °F, hold 10 minutes, cool to 110 °F. Less critical than for dairy since there is no whey protein to denature, but it kills competitors.
  6. Inoculate and incubate 6–10 hours at 110 °F. Plant milks generally ferment slower than dairy — taste for tang rather than watching the clock.
  7. Chill undisturbed.

Notes

PROVENANCE. Mine, arrived at after the plant-milk yogurts I bought were all either thin or full of gums.

WHY SOY IS DIFFERENT FROM EVERY OTHER PLANT MILK: dairy yogurt sets because acid destabilizes casein micelles, which link into a continuous protein gel. No plant protein does that — except soy, whose glycinin and beta-conglycinin do gel on acidification. That is why soy yogurt needs no thickener and coconut, oat and almond all do.

STRAINED, this is as good as dairy Greek yogurt. I will defend that.

REGULAR DAIRY YOGURT CULTURE WORKS on plant milks, which surprises people. If you need it strictly vegan, vegan starters are widely sold. Backslopping is less reliable than with dairy — plant substrates do not hold the two organisms in balance well — so expect to restart more often.

It tastes clean but beany. That is soy, not a fault.