Grapes

Grapes keep 1–2 weeks refrigerated, and like berries they should not be washed until you eat them.

Store them in the crisper, ideally in a ventilated bag — the perforated bag they came in is designed for this. They need some airflow but also high humidity, since they lose moisture through the stems and the fruit shrivels.

Keep them on the stem until eating. Detached grapes lose moisture and spoil far faster through the scar where the stem was attached.

Do not store grapes near strongly aromatic foods; their skins absorb odors readily.

Grapes freeze extremely well and frozen grapes are excellent eaten straight from the freezer, keeping for several months. Freeze them on a tray first so they do not fuse.

Grapes keep better than most soft fruit because of their skin: a genuine waxy cuticle, visible as the dusty bloom on the surface. That bloom is a natural coating the fruit produces, and it is a moisture barrier and a partial microbial barrier both. It is also the reason not to wash grapes until you use them — washing removes it.

The characteristic failure is gray mold, Botrytis cinerea, the same organism that takes berries. It grows at refrigerator temperature and spreads by contact, so one soft grape infects its neighbors. Sorting through a bunch and removing failures genuinely protects the rest.

The other change is dehydration: grapes shrivel as they lose water through the stem attachment. That is a quality decline and perfectly safe — a shriveled grape is on its way to being a raisin.

The stems tell you a great deal. Fresh grapes have green, flexible stems; as they age the stems turn brown and brittle and the grapes begin dropping off at a touch. The stem condition is usually a better freshness indicator than the fruit itself.

Discard grapes that are mushy, leaking, moldy, or smell fermented and alcoholic.