Back on the Yogurt Train: How to Make Yogurt

This is how I want my yogurt.
Dadiah, traditional West Sumatran water buffalo yogurt, fermented in bamboo segments. Courtesy of Wikimedia. Photo by Meutia Chaeran.
Mrs. Homegrown here:
One reason I make a lot of my own stuff is because I’m trying to avoid plastic packaging. And as I’m sure you know, that’s pretty much impossible these days–but I do what I can. Lately I’ve realized that one consistent source of waste plastic in our kitchen comes in the form of yogurt tubs. This is a little silly, because we know how to make yogurt. In fact, I do believe we covered it in our book.
Thing is, back in the day when we made yogurt, it was Erik’s job. When he slacked on it, I didn’t even consider picking it up. Chalk it up to the mysteries of division of labor in a household.
Anyway, we went to see Mark Frauenfelder talk about his great new book, Made by Hand, and one of things he mentioned was how much he and his family are digging making their own yogurt–and how cost effective it’s been for them. He inspired me to get back on the yogurt train.
It’s so darn easy, we should all be on the yogurt train. One great thing about it is that it not only saves money, but it saves packaging, and gives you more bang for your milk buck. We only use milk for coffee around here, so sometimes our milk goes bad. Now we make most of it into yogurt and there’s no waste, no excess packaging. And if we make some of that yogurt into yogurt cheese or use it instead of sour cream, that saves more packaging.
How to Make Yogurt:
Here’s how I’m making yogurt these days–it might vary a little from Erik’s methodologies in our book, but all yogurt making is basically the same. You’ll need a cooler for this.
Gather together:
  1. A cooler to keep the yogurt warm while it ferments. I’m sure there are many ways to keep yogurt warm, but I find the cooler straightforward, and that’s what I’m going to describe here. We make two quarts at a time in a little six pack cooler.
  2. Very clean canning-type jars
  3. Hot water bottle (optional)
  4. Towel(s) for insulation
  5. Your last store bought container of yogurt. You need live yogurt to start the culture, only a few spoonfuls. The label should say something about containing live, active cultures. You’ll need 1 Tablespoon of live yogurt for every quart of milk you’re transforming.
  6. Milk, of course. Make sure your milk doesn’t say “Ultra Pasturized” or UP on the label. That stuff is just nasty. Otherwise, you can use whole, 2%, 1% — and even skim, I presume, though I’ve never tried it. How much milk? As much as you want. But it seems to me that for the trouble, a quart would be the minimum it would be worthwhile making. After all, it keeps a long time. 
The procedure:
  • Heat milk gently to 180 degrees Fahrenheit. If you’ve got a thermometer, great. If you don’t, 180F is where the milk starts to simmer. Just watch for those first tiny bubbles to start rising. When they do, turn off the heat. (Heating the milk makes for thicker yogurt. You could skip this step if you like. I would skip it if I got my hands on some nice raw milk.)
  • Let the milk cool down to about 110F. This is the only hard part–waiting for it to cool. 110F is about as hot as a hot bath. You can put your finger in it and keep it there.
  • While you’re waiting, boil water to heat your jars. I like to fill my jars with boiling water, cap them, and let them sit until it’s time to use them, at which point I pour the water out. I know it’s not really sterilization, but it’s something, and it pre-heats the jars, which is important. You could also pull the jars straight from a hot dishwasher, or actually boil them. Also, you’ll want to pre-heat your cooler. Pour hot water in it as well and let it sit until the last moment. And fill up your hot water bottle, if you have one.
  • Stir in 1 Tablespoon of yogurt for every quart of milk in your pot. Use no more than that. Stir until dissolved.
  • Transfer the inoculated milk into warm jars, cap them, and stuff them into the warm cooler (which you’ve emptied of water). Do all this fast so you don’t lose much heat. Your mission is to fill the cooler up, so there’s no empty space, with some combination of jars of yogurt, towels and heating devices like hot water bottles or lacking one of those, just more jars filled with hot water. My routine is to put 2 quart jars in a six pack cooler, slide a hot water bottle between them, and pack the top of the cooler with an old towel, so that I can just barely manage to lock the lid in place.
  • The goal is to keep the yogurt very warm for about 8-12 hours. You might not be able to keep it at 110F the whole time, but it should be in that neighborhood. Certainly above body temperature. My set up described above seems to do that well enough. I’ve never checked the temp. inside, fearing to lose the heat. It just works.
  • After 8-12 hours the milk in the jars should look yogurty and taste yogurty. It might not appear thick enough, but remember that it is quite warm. It will thicken some after it goes in the fridge.
  • If it doesn’t look yogurty at all, add a smidge more starter, rewarm the cooler and everything, and try it again for another 8 hours. Consider that your starter–your store bought yogurt–may not be alive. Either that or the cooler wasn’t warm enough.

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16 Comments

  1. You can also use older stoves with pilot lights instead of a cooler to maintain heat. The inside of our stove always stays warm enough to culture the yogurt from the heat of the pilot light alone–we just pour into jars and stick it straight into the oven. Yet another added bonus of old stoves!

  2. I think its important to use starter from your last batch – I think you start to cultivate yogurt that is acclimated to your fermentation method and to the milk you feed it. I haven’t tried to scientifically confirm that, but I find that the first batch with a new starter is less solid and takes longer to ferment. The later batches are much more solid, and ferment easily overnight.

    I second the stove and pilot light!

  3. We’ve been doing this for a while too, since we also don’t do much with milk, but one thing we’ve especially enjoyed has been getting raw milk and using the cream for sour cream. It keeps for around foreverish andi ts just one more non-plastic, non-branded item in our fridge!
    Raw milk is kinda hard to come by, a co-op we know drives to a far for it every two weeks, but local milk is so important, and it is the best yogurt/cream/cheese this side of town.

  4. @Whopper: using more yogurt than that is actually less effective. I don’t have the info. here right now to quote, but to my understanding, that T. to qt. ration is the correct combination of bacteria, space and food.

    And you Anons, thanks–yes, the stove and the crockpot are good methods. We don’t have a crockpot to experiment with. We do have an old stove, but for whatever reason the pilot doesn’t keep it quite warm enough for yogurt. I’ve heard that newfangled ovens have low temp settings that might work, too. So it all depends on what you have to work with.

    @Herself: I’ve been wanting to try raw cream yogurt. Yum! It’s just a pain to source it around here, so haven’t yet. Call me jealous of your co-op.

  5. For Whopper’s info- it’s a space issue- you need enough space for the culture to grow.

    I learned how to make yogurt from my Jordanian neighbor, and she showed me the Arab way to do it, which included starting with a gallon of whole milk and a half gallon of half and half; boiling it; cooling it until you can comfortably leave your finger in it for a count to ten; pouring it into a clean pot with a lid; wrapping the whole thing up in a blanket and leaving it overnight in a non-drafty place. Lo! and Behold! it worked. However, I cut it down from six quarts to one, and made it a little more scientific- boil three cups of whole milk and one cup of half and half just until it comes to a boil. Pour into a clean jar, cap it, and let it cool for an hour. When you can hold your hand to it, take an instant read thermometer to it- if it’s higher than 110 degrees, let it cool another five minutes until it doesn’t read any higher than 110. Add your yogurt starter or 1 tablespoon of plain, unfettered yogurt, stir, cap and put into your yogurt maker (I have a Salton). Let it do its thing for at least six hours, but no more than seven. The longer you leave it, the more sour it will get.

    Anyway, everyone should try it from whole milk and half and half at least once, because it’s truly amazing yogurt.

  6. I have used the blanket method as Paula described all my life but I tried to use my dehydrator just to see how that went and it worked just as well, but faster. I’m not that interested in speed so probably won’t try it again but at least I know that it works. The recipe in the dehydrator booklet called for an addition of dried milk. I thought that made the yogurt creamier.

  7. @Cheryl:

    I don’t know, because I’m the opposite of you and dislike flavored yogurt! 🙂 My guess would be that you’d add vanilla during the cooking stage, and stir in fruit when it’s done, just before you put it in the fridge.

  8. Huh. What I do for my huge family is warm a gallon of milk between 150-160, wait to 110, put in a tub of Greek styled yogurt and then wait @16 hours *( I pop the oven on 100, then stick the big pan in and turn it off). Comes out sour cream thick. When I simmered it to 180 I got cottage cheezy looking stuff that got runny as soon as I stuck a spoon in it.

    I will try your way once more.

    Briana

  9. @Briana,

    Your method sounds great–you should stick with what works for you. I wonder if you need to add a whole tub of yogurt, even with a gallon of milk. Have you tried using less?

  10. I SHOULD try using less, but I’m so afraid to. But my kids LOVE it when I mess up a batch-I just make pudding. 🙂

    Yogurt is so weird. Like bread.

    Briana 😉

  11. Hrm, thanks for sharing but I think I need to try again tonight. When I look at the yogurt this morning it looked/tasted just like warm milk…maybe it’ll setup today. I’m glad to know I can just try again and not waste it.

    I used a thermos that I tested the day before and it held the heat perfectly at about 110. It only lost 2* in 10 hours.

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