These best way to know when farro is done is by tasting it: the grains should be plumped up (similar to barley); and when you take a bite, it should be tender and pleasantly chewy. If it's not done, just keep simmering. Depending on what variety you use, cooking times will vary: Pearled: 15-20 minutes Semi-Pearled: 25-30 minutes Whole Grain: 20-60 minutes, depending on soaking time