Make Greek Yogurt at Home

For those who, like me, like yogurt but wish it was thicker, Greek yogurt will be a delicious surprise. In Greece, this delicious treat can be found in every mini-market and grocery, but what if you aren't in Greece? Greek yogurt can be found in American specialty food stores and even regular groceries in areas with significant Greek population, or you can make it at home. Making Greek yogurt at home isn't difficult or expensive, and it doesn't require any special equipment. Just follow these steps to save money and enjoy fabulous yogurt or make your own authentic tsatsiki.

Supplies you'll need:

1. Whole Milk (you can, indeed, use lower fat milk but traditional Greek yogurt is made with full fat cow's or ewe's milk.) You will need approximately twice as much milk as you want yogurt. Any animal milk will work; soy milk yogurt can be made, but it requires a different technique an ingredients.
2. One unopened plain yogurt with live active cultures. The container will say 'live culture.'
3. A pot large enough to hold your milk.
4. Containers for the finished product, with lids.
5. Cheesecloth or a thin tea towel.
6. A colander and a bowl, approximately the same size.
7. A wisk
8. A large spoon.
9. A food or candy thermometer.
10. A sturdy pair of tongs.

Yogurt is made by adding specific bacteria to milk. The difference between this process and spoiling is the type of bacteria. In the US, a product is only called yogurt if it is made with Streptococcus thermophilus and Lactobacillus bulgaricus, though sometimes other 'healthy' bacteria are added also. When making yogurt at home, we must be sure to not contaminate it with any unwanted bacteria. While you can find success using clean utensils, I've found that for subsequent batches it is best to use a more sterile technique.

The first step, therefore, is to boil all utensils and containers for a few minutes and thoroughly wash your hands. Use the tongs to remove everything from the water and let all containers and utensils air dry. Boil the tea towel along with everything else and hang it to dry.

Next, heat the milk to 185 F and hold it at that temperature for 30 minutes. This process makes the texture of the final product firmer and smoother.

Cool the hot milk to 110 F. You can allow this to happen at room temperature or put the pan in a cold water bath. The yogurt bacteria grows very well at this temperature. Open the plain yogurt and stir it to break it up. Add one tablespoon (or the whole container) of this yogurt to the warm milk and wisk gently, taking care to not stir in air, which will slow bacteria down.

Keep the mixture at 110 F for 3-4 hours. This can be done in an oven with a very low setting or in a cooler. If using the cooler, boil some water and pour it into jars. Put both the jars and the milk mixture in the cooler and close the lid. If the holding temperature is lower than 110 F, the yogurt will take longer. If the holding temperature is below 100 F, the bacteria might stop reproducing altogether. But take care, if the temperature goes too high, you will kill the bacteria and have to begin again with a new culture.

While the yogurt is incubating, leave it still or the solidifying will be interfered with. After 3 hours, check the yogurt. It should be softer than store bought but still much thicker than milk. If it is still quite liquid, leave it in the warm and check it again every 30 minutes. If it is thick (sometimes slimy) it is time to go to the next step.

Put the colander over the bowl and line the colander with the tea towel. Pour about a cup of the yogurt mixture into the tea towel. Liquid will begin to drip through. If the liquid seeping out starts out cloudy (milky) but soon becomes transparent, the yogurt is ready. The liquid also may not be cloudy at all, and that is fine. If either of these two, transfer all the yogurt to the colander. It's a good idea to cover the yogurt with plastic wrap to keep out airborne contaminants. Fold the ends of the tea towel over the plastic wrap and place the whole thing in the refrigerator.

If the liquid continues to be milky for longer than 30 seconds, your yogurt needs some more time. Put it back in the heat for another half hour, then repeat the test.

Allow the yogurt to drain until the liquid drained off is a little more than 1/2 the volume of the original milk. If you started with a gallon, the yellowish liquid should be a little more than half a gallon. This process can take an hour or several hours. At the end, you have Greek yogurt. Transfer it from the tea towel into a storage container, cover and refrigerate. Eat it within a week or so, though yogurt can stay good for much longer in the right conditions.

In Greece, this yogurt is used to make tsatsiki or eaten plain or with honey or fruits preserved in syrup. In our house, we also use it in place of sour cream, to make dips, and as an accompaniment to spicy soups. Enjoy!