strainer suspended over a measuring cup or bowl. The yogurt should Not contain gelatin or added starch. There should be enough room in the receiving container to hold a cup of liquid without touching the strainer. Cover with an inverted plastic bag and put in the refrigerator for 8 hours or overnight. Depending on the yogurt used, the volume will reduce to about half, or 15 ounces yogurt will yield about 1 cup drained yogurt.