Making Homemade Yogurt in a Cooler

I make this recipe about once a week. We have a cooler that holds 6 wide-mouth quart jars, and we use about a jar a day, so that works out well. I like this recipe because it's so flexible - you're only limited by the size of your cooler.

Homemade Yogurt in a Cooler

6 quarts milk (or however much you have room for in your cooler)

2 cups plain yogurt (I like Dannon Naturals) – or you can use homemade from a previous batch

In a double boiler (I use my stock pot inside my smaller canning kettle - they fit together without too much extra space. Use whatever works best for you) warm the milk to 180 degrees (to kill any possible pathogens - if you're using raw milk that you're confident is safe, and you want your yogurt to retain those valuable enzymes, you can skip this step and just warm the milk to 110 degrees). Once you’ve reached this temperature, turn off the heat and cool to 110 degrees (use a candy thermometer to be sure (and, as I found out after multiple failed batches, make sure your candy thermometer is accurate!)

Meanwhile, warm your starter by scooping about 1/3 cup into each quart size jar (or whatever containers you're using) cover (I like these covers, but regular screw-band type lids work fine; you can reuse washed old lids, since they don't have to seal), and place these into your cooler. Pour warm tap water into the bottom of your cooler (not too much, or your jars will float! You want the water to be about 110-120 degrees; it feels pretty warm when you put your hand in, but not too hot to hold it there. This is the temperature my water comes straight from the tap on its hottest setting; different water heaters may be set at different temperatures. Many families set their water heater to 120 degrees so it can't scald small children straight from the tap.)

When both the milk and the starter are at 110 degrees, ladle the milk into your jars over the yogurt and put the covers back on. Place them in your cooler and cover with more warm water (just below the rim of the jars). Put the cover on the cooler and let sit for 4 or more hours (overnight is fine; it will get more tart the longer it incubates). When you're done, take it straight from the cooler to the refrigerator. Homemade yogurt will be runnier than store-bought, but it will thicken some when refrigerated (My yogurt is only slightly thinner than store-bought. I don't add powdered milk or gelatin, but I use whole milk, so that might make a difference). Add sweeteners or fruit after yogurt has set (we generally mix in blueberries and strawberries right before we eat it).

I like this method better than the crock pot method because you don't disturb the yogurt after it's set, which I think can make it runnier. Plus my crock pot is generally being used for other things! ;)

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If you, like me, prefer to print out a short-and-simple recipe without all the extra jabber, here you go:

Homemade Yogurt in a Cooler
6 quarts milk
2 cups plain yogurt
Heat milk to 180 degrees, then cool to 110. Warm 1/3 cup starter in each quart jar by placing jar in warm water in cooler. When milk is at 110 degrees, mix with warm starter. Add warm water to cooler just up to jar covers. Cover cooler and incubate at least 4 hours. Store in refrigerator after incubation period.

UPDATE:
If you're using raw milk and aren't heating it above 110 degrees, you can mix in your starter with your milk straight out of the fridge, warm it up, and ladle it into your jars without heating the starter separately. So my routine is now simply taking the milk and about 1 cup of starter out of the fridge, stirring it together in my double boiler pot, and warming it to 110 degrees F. Then I ladle it out into jars and incubate it in the cooler full of warm water for 6 hours or so (before breakfast to after supper - I'm not too strict on the timing). So simple! Just be careful not to heat it over 110, or you'll kill your starter.

 This post is a part of Real Food Wednesdays.