Place several layers cheesecloth in a fine mesh strainer.
Pour the yogurt into the strainer.
Allow to rest on the counter or in the refrigerator until it reaches the desired consistency, about 2 hours.
About 2 cups of whey should be strained for Greek Yogurt.
Notes
For Greek Yogurt, you will want to strain off about ΒΌ cup of whey for every cup of yogurt. If you start with 2 quarts of regular yogurt, that will yield 6 cups of Greek Yogurt and 2 cups of whey. Measuring the whey is a good indicator of when to stop straining.