Yogurt is something that I’ve always wanted to make myself, but didn’t want to invest in a machine (who has the space?) and wasn’t quite comfortable with the oven method (the yogurt ferments in an oven wrapped in a towel with the light on–which supposedly keeps it at 110 degrees F or 43 degrees C). But then I found out about the cooler method! What genius! By placing the jars in an insulated cooler filled with 110 F/43 C degree water, it retains the heat for the duration of the fermentation process (6 to 8 hours). For extra insurance, I line the cooler with an insulated tote I got at a supermarket a few years ago, since it’s suposed to retain heat for up to 8 hours….and I’m still a little paranoid.
****Note: Only use pasteurized milk to make yogurt. Ultra-pasteurized milk does not always inoculate properly, so I don’t even bother. You can get organic, pasteurized milk at your local farm(ers market), Whole Foods, and stores that sell Ronnybrook farm milk (if you live in the NY tri-state area). I also use whole or 2% milk because the less fat content, the runnier and less creamy the yogurt.
****Also, note: The starter culture you use is very important. Websites such as Cultures for Health sell heirloom and other varieties (which are really fantastic such as Viili) or you can use any yogurt with active cultures (such as fage and other greek or icelandic yogurts). Use only plain yogurts without added thickeners or sugars (I wouldn’t recommend anything with fruit on the bottom or even greek-style yogurt since they add pectin to make it thick, rather than remove the whey. Always look at the ingredients list! Scam artists.).
- pasteurized milk (ideally organic)
- yogurt with active cultures (1 tablespoon per quart jar)
First sterilize the jars you are going to culture the yogurt in it (boil them for at least 10 minutes). Some recipes say you don’t have to, but I feel it’s always better to be safe than sorry. Plus, you can then cool down the water to 110 F / 43 C to use as the water bath in the cooler.
Next heat the milk to a 180 F / 46 C, constantly stirring to avoid burning the bottom. Once it reaches 180 F / 43 C (you’ll notice little bubbles start forming around the edge), test it with a thermometer and then turn off the heat. Place to the side and let cool to between 110 -115 F / 43 – 46 C.
Once the milk has cooled to the right temperature, place 1 tablespoon of yogurt in each of the jars (if they are pint sized, you need only add 1/2 tablespoon). Pour the milk in and mix. Screw the caps on. Pour 110 F / 43 C water into the cooler (it’s easiest to use the water you boiled the jars in. You may need to adjust the temperature with tap water if it’s too hot). Next add in the jars and close the cooler. You can ferment the milk for 6-8 hours. I usually find that 8 hours with the starter I use (Dove Song Dairy Goat Yogurt, which buy the way, is probably the best goat yogurt I’ve ever had! The yogurt is so thick that I don’t even need to strain it.) is perfect. Remove the jars and place into the fridge for at least 6 hours (to stop the fermentation process) before eating. Your yogurt will apparently be good for up to 3 weeks in the fridge, although I generally make mine in one-week batches. And always remember, never eat it if it smells or looks funny! Sometimes a batch goes wrong, for whatever reason, and it’s better to be safe, than sorry. 🙂
Although the yogurt culture that i use makes pretty thick yogurt, you can also strain your yogurt in a cheese cloth (dripping into a bowl) over night in the fridge to make greek yogurt. Save the whey (the liquid that drains out) because it’s super healthy and can be used in many recipes!
Tip #1: Freeze one of the jars of yogurt in ice cube trays for future batches. One cube of frozen yogurt can be thawed to make 2 quarts of yogurt!