Yogurt revisited

[MajorChode]

I've been making homemade yogurt for years using a variety of different methods. Ironically, I've never owned a dedicated yogurt maker. I've incubated yogurt in an oven, a crock pot, a thermos, with a heating pad, and in a cooler filled with hot water. Lately I've been using my sous vide setup which makes things simpler and allows for more precise temperature control. Along the way I've learned a few things.

Basic ingredients:

Dairy
I've tried all sorts of dairy from skim to half-n-half and even goat's milk and soy products. All produce different textures and flavors. Generally I like to use good quality 1% milk with 1/2 cup of powdered milk added to each quart. Whatever you use, look for pasteurized and NOT ultra-pasteurized. I'm not exactly sure why ultra-pasteurized milk doesn't work, but I suspect that the very high temperatures associated with the process changes the milk proteins in such a way that you can't make yogurt with it. Personally I've never tried using ultra-pasteurized milk because I've always heard it won't work. If someone has used it with good results I'd be glad to hear about it.

Yogurt cultures
I've experimented with all sorts of cultures from the freeze dried varieties and plain yogurt that I've bought locally. What I've found works best is to find a yogurt that you like, and simply culture that to duplicate the taste. In order to get an exact match of taste and texture, you have to experiment around with milk types, and/or added powdered milk and varying the incubation times. You can use some of the yogurt you made as your culture for the next batch, but I've found that each batch made that way tastes a little different. Usually after 3-4 batches I'm ready to take a break from yogurt anyway, so I just buy a new starter when I'm ready to get going again or I usually keep some of the freeze dried stuff around if I don't feel like driving all the way to the boutique grocery store to buy some good yogurt to use as a starter.

Methods:

The first step to making yogurt is to heat the milk to sub-boiling. This step is very important. Many people think it's just to reduce the count on the "bad" bacteria. While this is certainly an important consideration, the main reason is to denature some of the milk proteins so the yogurt can thicken. Heat the milk to 185-200 degrees F for about 10-20 minutes. This methods will produce fairly thin yogurt, especially if you don't add powdered milk. For thicker yogurt, add powdered milk and heat treat for longer times, up to about 30 minutes at 200 degrees. I like to use a double boiler. If you don't use a double boiler, watch out for scalding, which you definitely don't want. You also don't want to boil the milk. After heat treating, put the container in and ice/water bath and stir until the temperature reaches 120 or so. Wait until the milk cools to 110 before you pitch your culture.

While lots of different methods for incubation work fine, the important part here is to incubate at between 100 degrees and 112 degrees. Too cold and you won't get proper incubation. Too hot and you'll kill your culture and/or the whey may separate. Generally I prefer warmer incubation(109-110) and longer times(6-8 hours) because it produces a better tasting result (for me anyway). I've found that about 109-110 degrees works pretty well, but precise temperature control is the key if you like using higher temperatures because the yogurt culture will start to die at 115 degrees. In general, longer incubation times mean the yogurt will have a more sour taste (which I like). If you incubate too long, they whey will eventually separate which is great if you are making cheese, but not so much if you are making yogurt. You will get a small amount of separation if you like sour yogurt, but if you get a lot you know it's time to go back and start over.

[wildflower]

1. This is a good point:

"the main reason is to denature some of the milk proteins so the yogurt can thicken. "

But I didn't realize it would help to keep it hot for a longer time. Thanks! I usually heat mine in the microwave, just to the boil, and then let cool for a little while before putting it in the thermos with my yogurt culture.

[MajorChode]

2. This is the hardest part of making good yogurt

If you allow the milk to boil, you'll get a very different texture. It won't be smooth like commercially made yogurt. One thing I forgot to mention is the fat content of the milk will also affect thickness. The higher the fat content, the thicker the result will be. This is the "easy" way to get thicker yogurt, but naturally more fat means more calories. There's also a couple of tricks for getting low-fat yogurt thicker besides adding powdered milk. You can either just drain off the whey, or you can line a colander with a couple of layers of cheesecloth and allow the yogurt to drain overnight in the fridge.

[Sparkly]

4. Is that what makes Greek yogurt so wonderful??

I love that stuff!

[noamnety]

3. Thank you for posting this.

I've been making yogurt weekly for months. I use a thermometer to get it up to temperature and whole milk or 2% with powdered milk. I certainly don't use exact temperature control once it's cooled and fermenting - I just put it on top of the gas oven and the pilot lights add the warmth.

What I didn't know was that keeping it at a the high temp for longer made for thicker yogurt, I'm going to try that next time.

[Mira]

5. This is fascinating and welcome information. You are obviously a yogurt making pro.

I make yogurt all the time, with a yogurt maker I found at the Salvation Army store for a buck.
I will now keep the milk good and hot for a while; I so far microwaved it to just below boiling and let it cool to 115 naturally, when I stirred in the powdered milk and then the starter, but now I will wait til it's 110.
I no longer eat store bought yogurt.:)

(I still remember my amazement over your flight photos from Glen Canyon/Arizona)

[MajorChode]

6. I'm not a pro, I'm just always searching for the perfect yogurt

I still buy store bought yogurt, but I'm generally not happy unless it's some pretty good stuff which usually means going to the boutique markets for the good stuff. When I find one I like I use it for starter.

(If you liked my last pictures, try this one taken earlier this month)
Dial-up warning!
http://tinyurl.com/2g8csvb

[Mira]

7. I'm so honored for you to reply and send this.

I now studied up for a good long while about Bighorn Canyon, and added it to my list of "if at all possible I want to go there" places.

Thank you!!!