What happens if I skip the denaturing step when making yogurt?

April 5, 2018 1:51 PM

My homemade yogurt frequently has a grainy texture and I’m trying to figure out how to fix it. There seem to be differing opinions about what causes this, including heating the milk too quickly, stirring the milk too much, and using a bad starter. I’m wondering what would happen if I skipped the initial high-heat step that’s meant to denature the milk proteins and kill competing bacteria. Is this a bad idea?

I’m using an Instant Pot for the common yogurt-making process of heating full fat dairy milk to about 180F/82C, dropping it back down to a warm, bacteria-friendly temp, adding the culture, incubating for 9 hours, and then chilling in the fridge to let it set.

Since the milk I use has already been (gently) pasteurized, the initial heating step seems to be more about denaturing the proteins to achieve a thick, creamy yogurt texture than for killing off unwanted bacteria, right? So how important is the protein denaturing process? Can I still get a decently thick yogurt without it, or will the result be runny and likely contaminated?

posted by theory to Food & Drink (8 answers total)

Best answer: I have attempted skipping that step, and the result was not yogurt. It was not thickened and it didn't seem like the culture actually took off—it didn't taste sour. You can try skipping it for a batch, and see how it works for you, though.
posted by BrashTech at 1:59 PM on April 5, 2018

Best answer: Yeah, I have screwed up the heating so it didn't get high enough and what you get is...not yogurt or even yogurty.

Except for that one time (unplugged the pot, then got flustered and didn't finish properly), I've never had grainy yogurt in the IP. I don't do any deliberate stirring until after it's off the heat (and then just to make sure it didn't scorch on the bottom), and I sometimes sink-cool quickly and sometimes counter-cool slower. I do always use storebought for starter, pretty freshly-opened.
posted by Lyn Never at 2:26 PM on April 5, 2018

I make yogurt in the instant pot and my trick to really good texture is this: after the first step, when it's around 180 and the alarm sounds, take off the lid, set it as if you're going to repeat that step (yogurt/boil) set a timer for 5 minutes and leave the lid off. This keeps it at that temp for five minutes without letting it boil. Then proceed with cooling , etc... For some reason this makes it creamier (I've read why, but don't remember)

Also, if you want thicker (Greek) yogurt, you need to strain it. I use a nut milk bag in strainer. You can do it overnight for very thick yogurt or for just a couple hours for much less runny.
posted by tangosnail at 2:45 PM on April 5, 2018 [2 favorites]

I only heat the milk to 160 degrees per Cultures for Health instructions. I also had some problems with graininess that was corrected by heating more slowly.
posted by Botanizer at 3:06 PM on April 5, 2018

Best answer: This Old Gal's IP recipe is the answer to all of your problems. Read the whole post.
posted by k8t at 3:30 PM on April 5, 2018

This happened to me when I was adding too much starter. Make sure you're only adding one tablespoon per quart of milk.

Also, you probably don't need to refrigerate it at the end. It should gel on its own - I always leave it overnight to give it plenty of time.
posted by toastedcheese at 3:41 PM on April 5, 2018

To actually answer your question, as I recall Sandor Katz says you don't absolutely need to heat it up to 180 degrees, but you will probably get more consistent results if you do. I've never tried skipping this step myself.
posted by toastedcheese at 3:43 PM on April 5, 2018

Have you tried the cold start method using ultra pasteurized milk?
posted by pecanpies at 5:18 PM on April 5, 2018