The ABV we show for a wine comes from listings for that exact wine and vintage that we have matched from around the web — producer pages, retailer pages and wine databases — not from a single supplier.

ABV is held against a wine and a year, so two vintages of the same wine can legitimately show different figures. That is usually correct rather than a mistake: alcohol moves with the growing season.

When you edit an ABV, you are not overwriting our number — you are laying yours over it. Ours stays underneath, which is why the web app's edit box tells you what our data says while you type, and why resetting brings ours straight back.

If we have not found a figure for a wine, the Structure section says Unknown ABV rather than guessing. The bottle in front of you is the best source there is, so read it off the label and enter it yourself. If our figure is present but wrong, you can correct it the same way, and report the wine so we fix it for everyone.