Question About Yogurt And Yeast

[ArtGirl]

I have made three batches of coconut milk yogurt. The first two came out fine. The third one cultured yeast. I'm wondering how this happened and how I can prevent it from happening again.

The first two batches were started with (first) commercial cow's milk yogurt, and (second) some yogurt from the first batch. They contained canned coconut milk (with guar gum) and added honey and gelatin.

The third batch contained the same coconut milk, honey and gelatin, but was started from emptying a capsule of non-dairy probiotic into the c. milk (ingredients: l. acidophilus, cellulose, L-leucine.

Could the yeast have come from the probiotic? Or was it somehow just in the air? I sterilize the jars in boiling water before filling. I bring the c.milk to a boil before adding honey, gelatin and the starter.

Any thoughts on this?

I ended up throwing the yogurt out becuase even after skimming off the yeast and some of the uppermost part of the yogurt it still was permeated with a yeast flavor.

[ShayFL]

Well I'd have to guess the probiotic. Yeasts can also grow from the air it is true. But all things being equal, my money is on the probiotic.