To strain yogurt using a coffee filter, follow these steps: i. Place a coffee filter in a fine-mesh sieve or strainer. ii. Set the sieve over a bowl or container to catch the liquid (whey) that drains out. iii. Spoon the yogurt into the coffee filter. iv. Allow the yogurt to drain in the refrigerator for several hours or overnight until it reaches your desired thickness. The longer you strain it, the thicker it becomes.