Checking a bottle before you buy it.

A great label is a claim, not a guarantee. Between the estate and your table a bottle may have crossed three owners, two warehouses and a summer in an unrefrigerated container. None of that appears on the front label and all of it decides what is in the glass.

The instinct most buyers have is to worry about counterfeiting. Outside a handful of trophy names, that worry is usually misplaced. The common failure is far duller and far more likely: heat. A wine that spent three weeks at thirty-five degrees is not a bargain at any price and nothing on the label will tell you it happened.

Five checks catch most of the trouble. A serious merchant answers all five without being pushed. If they cannot, that is itself the answer.

1. Fill level

Wine seeps past a cork over decades and heat accelerates it sharply. For Bordeaux, a fill at the base of the neck is excellent at any age and top shoulder is normal from about twenty years. Mid-shoulder on a wine that should still be young is a heat story, not an age story and you should price it as such or walk.

Burgundy is read differently because the bottle shape has no shoulder to reference. There you are looking at the distance from the base of the cork, usually described in centimetres. Compare like with like and be suspicious of any seller who will not quantify it. Both bottle shapes are covered in what fill levels tell you about an old bottle.

2. The capsule

Look underneath it for seepage staining and check whether it turns freely. A capsule that spins is usually a good sign, because it means nothing has leaked and dried. One that is glued in place by old wine is not.

A capsule that looks conspicuously newer than the label deserves a direct question. Recapsuling is legitimate when an estate does it during a reconditioning programme and it is a red flag when nobody can say who did it or when.

3. The label

This is where instinct misleads people. Cellar-damp labels with lifted corners and a little mould are a good sign, not a bad one: they suggest a cool, humid cellar, which is exactly where the wine should have been. Bin-soiled and nicked is honest.

A pristine label on a forty-year-old bottle is worth asking about. It may simply have been stored in a case. It may also have been cleaned or replaced, which on a famous name calls for the checks that expose a counterfeit.

Condition matters more than vintage for anything over fifteen years old. A great year badly kept is worth nothing.

4. The paperwork

Ask three questions, in writing. Where has the wine been stored, for how long and did it move under temperature control? Did it come from a single source or was the lot assembled from several? Is there anything on file, an original invoice, a bonded warehouse record, an auction lot number?

Single-source provenance with records is worth paying a premium for. An assembled lot is not disqualifying, but it should be cheaper, because you are buying an average of unknown histories rather than one known one.

5. The seller's own terms

Read what happens if a bottle is faulty. A merchant confident in their provenance will take back a corked or maderised bottle without an argument. One who sells strictly as-is on wines above a certain value is telling you something about their own confidence and you should listen.

Where the chain actually breaks

It helps to picture the route a bottle takes. Estate, then négociant, then an importer, then a retailer or an auction house, then you. Sometimes a private cellar sits in the middle, sometimes two. Every handoff is a loading dock, a van and a decision about whether to pay for temperature control.

The links are not equally risky. Movement inside Europe in temperature-controlled transport is usually fine. The dangerous ones are the transitions: the week a pallet waits for a sailing, the month a collection sits in a probate solicitor's storage unit, the afternoon a case is carried across a car park in August. Nobody logs those, which is why the paperwork you can get matters so much and why a lot that has moved once beats a lot that has moved four times.

This is also why buying directly from a well-run estate or from a merchant who bought on release is worth a premium over the same wine assembled from the secondary market. You are paying for a shorter chain. The same arithmetic applies when you import a case yourself from Europe.

Buying at auction, specifically

Auction is where most people meet older wine and it comes with its own vocabulary, which the guide to buying wine at auction explains in full. Read the condition report as well as the catalogue description. It is still the auction house's opinion rather than a guarantee, but it describes the actual bottles. Look for whether the house inspected the lot themselves or is relying on the consignor.

Terms to take seriously:

• As inspected. The house has looked at the bottle and is describing what they saw. Better than nothing and no warranty of what is inside.
• Ex-château or single-owner. Ex-château wine comes straight from the producer's own cellar; a single-owner lot is a whole collection from one source. Both usually offer the best provenance available at auction, because one history covers every bottle.
• No condition stated. Ask before you bid. If the answer is vague, bid as though the wine is compromised or not at all.
• Buyer's premium. Typically a meaningful percentage on top of the hammer price, plus shipping and sometimes duty at destination. Budget the all-in number, not the hammer.

Pre-sale viewing is open to anyone and almost nobody goes. Twenty minutes with the lots you care about tells you more than any catalogue and the staff will usually answer direct questions about where the wine came from.

What this costs you

Roughly one email. The reason to send it is not paranoia. It is that heat damage is common, invisible from the front label and completely unrecoverable. No amount of decanting fixes a cooked bottle.

The same discipline pays when you sell or pass wine on yourself. Keep your purchase invoices, keep the storage records and the next owner will pay you for the certainty. Those records also underpin valuing and insuring a collection. If the bottles sit in Asia, storage raises exactly the same questions.