Greek yogurt is made with whole-fat milk and strained to produce a thicker, creamier end product. It emulates the type of yogurt produced in Greece, and is commonly featured in Greek cooking in the form of sauces. Making Greek yogurt is similar to making regular yogurt, but it involves using a special yogurt culture, and straining to remove some of the water content to make the yogurt thicker. Goat's milk or sheep's milk can easily be substituted for whole fat cow's milk.
Warm the goat's milk at medium heat in a saucepan. Remove from heat once it starts to steam.
Pour the milk into one of your bowls, and let it cool to 104 degrees F.
Mix in 3 tbsp. of commercial or homemade yogurt into the warm milk. You may also use a commercial dried Greek yogurt culture instead.
Cover the bowl with a cloth napkin, and allow to sit at room temperature or a little warmer (if possible) for eight to 12 hours to "incubate."
Place the cheesecloth or muslin into the strainer, place the second bowl underneath the strainer to catch the liquid that will come out and pour the now-thickened milk from the first bowl into the strainer. Let the bowl and strainer sit in the refrigerator for a few hours until the desired consistency (thicker than normal yogurt, more like custard) has been reached.
Discard the whey (liquid), and store the remaining yogurt in an airtight container in the refrigerator.
Do not let the milk boil in step 1.
Do not move the bowl during step 4.
Do not use metal containers or bowls to hold the yogurt mixture at any point during the incubation process, as that can kill the yogurt culture and your milk will not turn into yogurt. A metal strainer during the straining process is OK.