There might not be any sadder sight in the kitchen than a container of fresh berries that’s gone moldy. While berries that are put into storage when still wet have an increased chance of spoilage, sometimes the berries themselves already have mold spores on them—a naturally occurring phenomenon for any food—and this causes them to go bad quickly. And once one berry gets moldy, the others will eventually follow suit.
To keep your berries fresh longer, first take them out of their container and remove any that show signs of mold. Also separate out any that are ripe, or starting to pass their prime; wash and eat them promptly.
Then follow these tips for the remaining berries:
For strawberries, blueberries, and blackberries, place them in a bowl at least three times the size of the quantity of berries. Add a 3:1 ratio of cold water and white vinegar and use your hands to swish them around in the water.
Pour the berries through a strainer, and rise with clean water. Do this several times, until you can no longer smell vinegar.
Lay out a double layer of clean kitchen towels, and pour the berries on top. Spread them out. If you’re in a rush, you can add another towel on top, and gently blot the berries. Otherwise, allow the berries to dry completely.
Store the berries in a ventilated container—like the green molded pulp containers you get at most farmer’s markets, or a mini colander. If you don’t have any containers with ventilation holes, place a dry napkin or paper towel in the bottom of a regular plastic container, pour the berries inside, and leave the lid ajar, to allow condensation to escape rather than drip down onto the berries.
Raspberries tend to be more fragile than other berries, so it’s best to rinse them with cold water just before eating.