Robert Mosolgo

How I Make Yogurt

Yesterday I excitedly recommended to a friend that he try making some yogurt at home. Then I realized that my personal recipe is a bit of a hodge-podge, so I thought I’d try writing it out.

This recipe isn’t perfect: when using raw milk, a bit of the cream still separates to the top while it’s culturing. (I’d rather have it all mixed in, but I guess you could call it “cream top”!)

My sources are:

I’d like to add pictures someday, but for now, I recommend the pictures on Fankhauser’s blog.

Prep and sterilize

Yogurt will only be as good as what you put in it. I generally sterilize everything I’ll need for the recipe:

  • A spoon for working with the starter culture
  • A bowl for mixing starter with milk
  • Jars for holding the yogurt, and their lids
  • A ladle for bottling
  • A funnel for bottling

To sterilize these items, I either:

  • Put everything in the dishwasher (without soap) ad let it run until the “sterilized” light is green; or
  • Put everything in a big pot with a few inches of water at the bottom. Boil the water and keep a slow boil for 10 minutes. (This technique is from Fankhauser, above.)

Sometimes I forget an item at this step, in which case I wash it as welll as I can and hope for the best. I’ve never had anything really spoil, but I did have a batch that had a bit of kefir taste to it! I assume it had some yeast contamination. I still ate it 🤷‍.

Heat the milk & hold

Fankhauser recommends this step for pasteurization purposes, to kill unwanted bacteria. Brod & Taylor’s recipe prescribes a higher temperature (195°F) and a longer holding time in order to mess with the proteins and get a thicker yogurt. (I really don’t know how it accomplishes that. I read that it “denatures whey proteins”, and anyhow, I’m convinced because this is the same temperature you use to make whey ricotta, so there must be something to it.)

Anyway, first, heat the milk to 190°F and then take it off of the heat for 20 minutes.

The real trick is not to burn the milk. Whenever I cook it in a pot on the stove, I burn it on the bottom, no matter how much I use low heat and stir. Burning the milk is a double-whammy: it caramelizes some milk sugar, giving a hint of weird taste to the yogurt, and it sticks like cement to the bottom of the pot (adding insult to injury).

Finally, I found an approach that doesn’t burn the milk. I put a 2-gallon pot of milk inside my canner (without a lid) and fill the canner with water, then use it like a giant double-boiler. Just like a double-boiler, the hot water will buffer the temperature (it can’t go above boiling), and as a bonus, it heats the milk faster and more evenly, since the pot is surrounded with hot water. When the milk reaches the target temperature, I take it out of the double-boiler and set it aside.

Cool the milk

The milk is now ready to become delicious yogurt, but it’s too hot for yogurt cultures to survive. Cool the milk to 120°F by placing it a sink of ice water. Stir frequently to equalize the temperature of the milk, and remove it when it reaches the target temperature.

Inoculate

Now, add the starter culture to the pot of milk. I’ve done it two ways:

  • Add a packet of thermophilic starter. This is easy and reliable. I buy the starter at Fifth Season Gardening downtown. The downside is, it’s more expensive than…
  • Or, add 1 cup of yogurt per gallon of milk (this is Fankauser’s ratio from the recipe above). You can use yogurt from your own previous batch, or use store-bought: find plain yogurt labeled with “active cultures” and a “use-by” date in the far future (so it’s fresh). When adding yogurt this way, first mix equal parts yogurt and warmed milk (from the pot) in a bow, and stir until the consistency is even. Then, pour this mixture back into the pot and stir. (This is Fankhauser’s technique. I assume it’s to ensure that the culture is evenly distributed.)

Bottle it

Now that your yogurt is inoculated, distribute it into your jars (or whatever) to culture. I make 2 gallons at a time, so I use 8 quart jars.

Set it

Put your jars in a cooler, and fill the cooler with 120°F water. (Actually, I prep the cooler by adding some hot water first, then dumping it out and refilling this. I hope it warms up the cooler ahead-of-time.)

I used to really fuss with the water temperature, checking it from time to time and heating it back up to keep it close to 120°F. But then, I read in the Brod & Taylor recipe (linked above) that you might get a better texture by reducing the temperature after 1 hour.

I don’t follow that recipe, but I do close the cooler and forget about it. It cools off on its own and seems to turn out fine. I also read somewhere (don’t remember where?) that temperature variance helps complementary cultures (Bulgaricus and Thermophilus) get their own time to work on the milk. Something like, one of the bacteria does better on the higher range, while the other does better on the lower range.

Forget it

I leave it for 8-16 hours, roughly all day or overnight. “Done” is a matter of taste. More culturing will make a tangier yogurt that separates whey more. Less time will make a sweeter yogurt with less whey separation.

I used to leave it for 24-ish hours, but I realized that the sweeter yogurt is tart enough and takes less time. Besides, I read on Brod & Taylor’s “How to Maintain a Yogurt Culture” that the culture will last longer if it has more lactose to digest while it’s in the fridge. I don’t follow all the steps in that article, but I hope it will keep my culture going strong for longer.

Eat it

Dry off the jars and put them in the fridge. They’re sterilized and pasteurized, so besides the yogurt bacteria continuing to process the lactose, they don’t really spoil. I make yogurt once every month or two.

We end up eating yogurt as:

  • milk for cereal
  • a vehicle for jam or honey
  • strained, as a replacement for sour cream
  • mixed into various sauces (herbs, garlic, etc)

I’d like to try making frozen yogurt, but I haven’t yet!