[rmosolgo]

A few updates since I first wrote this up:

- I don't bother sterilizing any more. I make sure the jars are clean, but that's all. I think the culture is fast enough to raise acidity to a safe point very quickly. (I still sterilize for cheese though.)

- I always use commercial culture now. I had off-results after the third round of saving a starter. (Someone mentioned heirloom cultures, which I think would avoid this problem. My wife tried those, but we didn't care for the flavor, and I prefer the workflow of two gallons at a time, done overnight.)

- If you make yogurt, but never started with the high-temperature initial step, I really recommend trying it. It makes a thicker consistency because the proteins are denatured and curdle better. (The downside in my opinion is that it also destroys some of the goodies present in my previously-raw milk.)

- My 20-minute high-temperature hold is often much longer. I try to reach 180 degrees F and take it off the heat, then put the kids to bed. It always seems to do fine.

Anyways, thanks for all the comments. I'm always happy to read a nice discussion about dairy processing! Next time you're passing through central Virginia, let me know and we can share a cheese plate.

[supahfly_remix]

How critical is the rate of cooling? Do you have to use an ice bath or can you use air cooling to cool it down?

I make my own yogurt using an instant pot for both the boil and incubate but cool using the air. Sometimes the consistency is lumpy, and I wonder if this anything to do with it.

[poulsbohemian]

One of the first times I tried using an Instant Pot, I was also using a starter (powdered, commercial) I'd not used before. It turned to cheese curds. I came to the conclusion that the Instant Pot got too hot for that particular culture. So, yes - it could be a combo of both temp and culture causing your lumpiness. I've noticed too with a different culture (yesterday's yogurt) that even after mixing thoroughly, it seems like it clumps back together and I've not been able to discern why.

[UncleSam]

My instant pot isn't consistent in temperature for saute or high heat. I heat up the milk in a separate pot and use an instant read thermometer to ensure it hits the correct temperature.

When you mix the culture into a small part of the milk, make sure to get that to a fairly smooth consistency before adding it to the rest. That also seems to help achieve a smoother result.

[chris_st]

I use my Instant Pot in pretty much exactly this way, but have never had lumpy yogurt, so maybe something else?

[ValentineC]

> If you make yogurt, but never started with the high-temperature initial step, I really recommend trying it. It makes a thicker consistency because the proteins are denatured and curdle better.

I wonder if using UHT milk (which is heated up to 135°C/275°F) would achieve similar results. It has the bonus of being sterile straight from an unopened packet.

I've been making kefir with UHT milk for a couple of years now, and it always seems thicker and creamier than some others I know who use fresh refrigerated milk.

[boudin]

I found that saving a starter really depends on what you start with. In our case we were using store bought yogurt (the yeo valley brand) and after saving the starter 2 to 3 times, it wasn't much active anymore. One day we bought a yogurt from a local farm and have been able to save a starter and re-use it for months, we are still using it. We make yogurt every week.

[serkandurusoy]

I live in Turkey where yogurt is an essential part of our diet and culture and nothing beats a homemade pot with a thick layer of cream on top.

I can assure you, you'll never need to buy any more starter, ever! As long as you save some for the next batch, you're golden! If you can use unprocessed milk purchased directly from a dairy farm, that's even better as I promise your tastebuds will rejoice! :)

[bergie]

Same experience with starting from store bought yoghurt, only got 2-3 rounds from it.

[serkandurusoy]

Since you seem to be really into making yogurt and like your science, I wonder, have you ever tried using "dew" as your starter?

There's an old (unfortunately dying) tradition in Turkey where dew you collect at sunrise during late spring, early summer can be used to ferment fresh milk to make the absolute best yogurt.

[jessaustin]

I don't bother sterilizing any more.

I'm glad to read this. I used to "make yogurt" by mixing a small container of yogurt into a gallon of milk and leaving it out on the counter for a day. The result was perfectly cromulent yogurt. Then well-meaning friends urged me to worry about sterilization, and I haven't made it since...