Two half-full bottles are in the fridge. One was opened yesterday, the other sometime last week, and neither has a date. You cannot recover that information by looking at the label. A short closing routine makes the next decision easier.
Put the bottle away before dealing with the record
For opened still wine, WSET recommends reclosing the bottle, keeping it upright and refrigerating it. Red wine belongs in this routine too: cooler conditions slow oxidation. For sparkling wine, use a sparkling-wine stopper; a vacuum pump removes bubbles. Source: WSET on preserving opened wine.
Then attach the date. A removable label or a note tied to the bottle is enough. Put the same date in any tasting record you keep. If you transfer still wine to another container, make sure the wine identity and original opening date stay with it.
Use this five-line bottle note
Wine and vintage: Opened on: Approximate amount left: Stored where / closure used: Next check:
For example: "2023 white; opened September 9; about half left; kitchen fridge, screwcap; check September 10." That next check is a reminder to assess the bottle, not an expiry date or an obligation to finish it.
For two open bottles of the same wine, distinguish them with a small A or B label. Keep their dates separate. Combining the notes would hide which bottle was opened first.
How many days does it keep?
WSET says reclosed red or white wine refrigerated after opening can remain relatively fresh for up to five days. Treat that as a general quality guide, not a promise for every bottle or a safety deadline. Read the source and its preservation advice.
A date label tells you elapsed time. It cannot establish the condition of the wine or compensate for an unknown storage history. Avoid a rigid chart that declares every red usable for one number of days and every white for another.
When you next intend to use the bottle, compare its aroma and taste with your original note if you have one. Note whether it still offers what you enjoyed. Do not keep pouring it because a countdown says a day remains.
Keep leftovers out of the unopened bottle count
Suppose you own six bottles and open one. You now have five unopened bottles plus one open bottle with some wine left. Recording six unopened bottles until the last glass is gone makes the cellar appear better stocked than it is.
Record the opening once. If the app tracks openings but not the remaining liquid, use the bottle label or a separate open-bottle note for the leftover amount. Do not imply precision by recording 375 ml unless you actually measured it; "about half" is often enough for this purpose.
When the bottle is finished or discarded, close the leftover note. Do not subtract it from unopened stock again. See the opening-history guide for preserving the tasting record.
Check the open bottles before opening a new one
Make that the first step when you next choose wine. If a leftover bottle suits the occasion and you still enjoy it, you have found an option already available. If it does not, keep that decision separate from its purchase price.
After a few occasions, look for the repeated problem. If dates are missing, keep labels by the storage spot. If two people open bottles without seeing the other's note, agree on a single open-bottle list using the household handoff routine. If leftovers are consistently unused, let that inform the quantity you open next time.