A good grape is juicy, sweet (with just a touch of tartness), and firm. Once a grape starts to get mushy, it becomes a bad grape. But rather than simply throw away a mushy grape, you can save it by simply tossing it in the freezer.
A frozen grape cannot be a mushy grape, and even an overripe, too sweet grape becomes edible once you freeze it (it’s basically a bite-sized popsicle). Just take the grapes off their stem, wash and dry them, then pop ‘em in a freezer bag and freeze overnight. Eat them as a snack, use them to chill a crappy wine, or toss them into a sangria. Now that you know this, you’ll never let grapes become food waste again, right?