Heavy Cream

Opened heavy cream keeps about 10 days refrigerated and 3–4 months frozen per FoodKeeper — notably longer than half-and-half, thanks to its higher fat content. Follow the package date if it is sooner.

Store it at the back of a cold shelf with the cap sealed. Cream absorbs odors readily, and whipped cream made from an onion-adjacent carton is a memorable mistake.

Most heavy cream in US stores is ultra-pasteurized, which extends the unopened shelf life substantially. The tradeoff is that UHT cream whips a little less willingly and holds its peaks less well; if you can find conventionally pasteurized cream, it whips better.

Cream freezes usefully but not for whipping — the emulsion breaks and thawed cream will not hold air. It is fine in sauces, soups, and baking. Whipped cream, however, freezes well: pipe rosettes onto a tray, freeze, and bag them.

At around 36% fat, heavy cream is the most fat-protected liquid dairy product, and it keeps longer than milk or half-and-half for that reason. More fat means proportionally less of the water phase where bacteria actually grow.

Cream fails in two ways, and it is worth being able to tell them apart.

Souring is bacterial: lactic acid bacteria surviving pasteurization ferment lactose into acid, eventually curdling the proteins. This is the same process as in milk, just slower.

Rancidity is chemical and enzymatic: lipases split the butterfat into free fatty acids, producing a distinctly soapy, waxy, or crayon-like smell rather than a sour one. Because cream is mostly fat, this route matters more here than in milk, and it is what limits the freezer window to 3–4 months even though the cream stays perfectly safe.

There is also a purely physical change: cream naturally thickens as it ages, and old cream whips faster but breaks into butter more easily. That is not spoilage, just a shifting fat structure.

Discard on a sour or soapy smell, visible curds or lumps in the carton, a yellow tinge, or any mold around the spout. Do not taste to check — this is not a case where a sip is informative.