Sunday, January 13, 2008
This method comes from an offhand mention in one of Elizabeth David’s books and I wish I could remember which one. She wrote that she made her yogurt – in a Thermos.
It was kind of a “Duh” moment; Thermos bottles are designed to keep the contents at the same temperature for an extended period of time, which is exactly what you need to make yogurt. Forget the fancy machine from Williams Sonoma with the Italian name. Dig out the thermos flask from the cupboard by the kitchen stairs where it is hiding behind the Off, the flashlights and the dog brush. Bonus points if it has Barbie or Spiderman on it.
You will need the Thermos, a large microwave proof bowl or Pyrex measuring cup (8 cups minimum), and a cooking thermometer that gives a reading of 130. I use the same thermometer we use for turkey. You also need a small amount of commercial yogurt to use as a starter, and the best milk you can get your hands on.
(We are lucky enough to get our milk from a local dairy that delivers it in glass bottles. The dairy owner keeps running for the Republican nomination for governor and losing. He should stick to milk. Politicians are a dime a dozen but a good dairyman is hard to find.)
First, make sure everything is clean. I put the kettle on to boil and then scald the thermos and the lid. Scalding not only gets rid of any bacteria that might be lingering in the Thermos from the last batch, it also preheats it.
Because I can’t put commercial thickeners in my yogurt, I like to cook the milk down a bit. I usually start with 2.5 cups of 2% milk and microwave it in 8-minute bursts, skimming that nasty skin off in between. It rarely takes more than two zaps before it is reduced to 1¾ cups. I have a 2-cup Thermos; if yours is larger, obviously, make more but you want to reduce the milk by about a fifth to a fourth. I’ve gotten great results by cooking it down by half, as well. Remember, you need room in the Thermos for the commercial yogurt starter so two tablespoons less than 2 cups is what I shoot for.
Take it out of the microwave, drop in the cooking thermometer, and let it sit until it has cooled to 130 degrees F. This can be speeded up a bit by pouring it into another measuring cup. Remove the skin, stir in one tablespoon of commercial yogurt per cup of milk, and pour it all into the Thermos. Cap it and let it sit for no less than five and no more than seven hours. The longer it sits, the tangier it gets.
When you open the Thermos you will see a creamy, semi-solid mass with a very small amount of whey on top. Pour this all into a clean glass jar and stick it in the refrigerator. Once it is cold, it is ready to eat. This has a fresh taste that beats the store-bought stuff twenty ways from Sunday. The entire prep process takes about half an hour and you can get the dishes done, change loads in the drier, and check your email while it’s going on. You can even cook down the milk one evening and reheat it the next before you go to bed, letting it ferment overnight. It's worth it.