Vietnamese yogurt: third time not the charm

I've recently made 2 batches of Vietnamese yogurt. Easy to do, lovely silky texture. Today I tried again and...not happening. After 4.5 hours, it's still liquid. Ironically, I used actual Vietnamese condensed milk this time, but I'm sure that's not it. No idea what went wrong - did it precisely same way, same starter....

So, I just put it in another hot water that futile? And if so, do you think I could chill the mixture, maybe whisk in a little vanilla or matcha, and turn it into a variation on frozen yogurt?

Here's the recipe, btw:



chefsusie June 14, 2012
Half pints comment regarding using a starter a few times is correct. Excess acid results when L. bulgaricus becomes dominant. This gives the yogurt a very "sharp" taste. How did the yogurt/ice cream turn out?
ChefOno June 14, 2012

Good to know, thanks.

HalfPint June 11, 2012
Only thing I can assume is that the waterbath was too hot. The waterbath should be 108-112F, it seems to be the sweet spot for good yogurt incubation. Another reason might be the starter that you used. Not sure what you mean by same starter (same starter used for prior 2 batches? using one of the prior batches as the starter?). You can only use your prior yogurt batch as a starter for a few subsequent runs (4-5 batches usually) before the culture becomes too weak (?) to produce a good yogurt batch. At that point you would have to use a yogurt starter culture or purchase new yogurt from the supermarket.

Putting the yogurt in another water bath is futile because the culture is already dead. Make a smoothie and start another batch with new starter. Check that temperature and make sure that it's not too hot or too cold, use a candy thermometer to check.
amysarah June 11, 2012
I think you're probably right about the temp. Might have been just slightly too warm. By same starter I just meant same type - for each batch, I used a fresh yogurt from the market (2% Fage.)

Oh well....I've already scraped it into a bowl, whisked in a little vanilla and am chilling it overnight. Will try it in the ice cream maker in the morning. Not a total loss.
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