Set a strainer or colander over a deep pan or bowl, supporting it so base of strainer is at least 2 inches above pan bottom.
Line strainer with 2 layers of cheesecloth or a clean muslin or linen towel. Dump yogurt into cloth. Enclose strainer and pan with plastic wrap to keep airtight.
Chill at least 24 hours or up to 4 days, pouring off whey as it accumulates. Shorter draining produces a moister cheese and more volume. Longer draining produces a thicker cheese and less volume.
Scrape yogurt cheese from cloth and use, or store airtight up to 9 days from when draining began. Drain off any whey that accumulates.