Have you ever brewed a cup of tea and only after taking a sip realized that it was way, way too bitter? You don't want to under-steep your tea, of course, as this makes for a watery cup, but bitter tea can be downright unpleasant. There are several reasons this can happen. For example, using low-quality tea, steeping the tea too long, using water that's too hot, or using water that just doesn't taste that good can make for a bitter cup of tea.