The cabinet is warm, the display is dark, or the power has been off since morning. Wine is not ruined by the first degree of drift, but the clock matters and so does the order in which you act.
First hour: keep it closed, find the cool place
A full cabinet is a large thermal mass. Every time the door opens it loses that advantage, so decide where the wine is going before you start moving it. Look for the coolest place in the home that will stay steady for days rather than the coolest place right now: an interior closet on a north wall, a basement, the floor of a wardrobe away from pipes and sunlight.
Steady matters more than cold. Wine keeps better at a stable higher temperature than in a place that swings between cool nights and warm afternoons. The storage comparison guide covers how to judge a spot with a thermometer over a few days rather than by touch.
Decide what moves first
Not everything needs to move, and moving everything is how bottles get broken and lost. Take the irreplaceable bottles first, then the oldest, then sparkling wine, then anything you plan to keep for years. Everyday bottles you will drink within a month can wait, and often do not need to move at all.
Carry them in the cases they came in if you still have them, and write the destination on the box. A rescue that scatters forty bottles across three rooms creates an inventory problem that outlasts the repair.
Record the exposure while you still know it
This is the step people skip, and the one that pays years later. When a bottle tastes stewed in 2029, the only useful question is whether it was ever cooked. A dated note answers it. Memory does not.
Failure noticed on: Last known good on: Highest temperature observed: Roughly how long above normal: Bottles affected: location or list: Where they were moved: Cause: power cut, compressor, door left open, unknown: Repaired or replaced on:
Keep that note with the collection rather than in a drawer. If you carry insurance on the wine, it is also the record an insurer will ask for, and the insurance guide covers what else to keep alongside it.
What heat does, and what you can see
Warm storage ages wine faster and, at the extreme, cooks it: fresh fruit turns stewed or jammy. Two physical signs are worth checking on any bottle that has been hot. A cork pushed slightly above the lip means the liquid expanded, and dried wine on the neck under the capsule means it seeped. Fill level is the same evidence read slowly, which is why buyers use it to judge condition, as Decanter describes.
The honest limit of all of this: many heat-damaged bottles look perfectly normal, and a normal-looking bottle is not proof of a wine that survived. The signs are useful when present and prove nothing when absent. For general storage temperature guidance, the WSET storage notes are a reasonable reference.
Before you refill the cabinet
Once it is repaired or replaced, let it run empty for a day and check that it holds temperature rather than trusting the display. Then move the wine back and correct the locations in your records as you go, one shelf at a time.
Open one of the exposed bottles soon, ideally one you can spare. It tells you what the exposure actually did, and the note you write turns a worry about the whole cabinet into a fact about one shelf.