Ketchup
Opened and refrigerated, ketchup keeps for about 1 to 6 months; unopened, often well over a year. Sugar and vinegar preserve it — it rarely spoils fast.
Why ketchup keeps so long
Ketchup is a small preservation marvel. Its high sugar, vinegar and salt content, along with its acidic pH, create an environment where bacteria and mold struggle to grow. That is why an unopened bottle often keeps well over a year, sometimes up to two. The printed Best-By date is calculated with plenty of caution.
After opening, the maker recommends refrigeration. Thanks to those preservatives ketchup would stay stable at room temperature for a while, but the fridge keeps its colour, flavour and texture best — usually one to several months. Left out on the table it loses quality faster and darkens. The exact time depends on the type: ketchup with less sugar or no added preservatives keeps less.
The reason ketchup still gets tossed too early is the misunderstanding around the Best-By date. Many throw the bottle out the moment the date passes, yet ketchup is unusually stable thanks to its recipe. A quick look at the colour, smell and the bottle rim tells you far more about whether it is still good than the printed date does.
How do I spot bad ketchup?
Spoiled ketchup is rare, but there are clear warning signs:
Coloured or fuzzy spots at the neck or on the surface mean discard it. Do not wipe and keep using.
A hiss on opening, bubbles forming, or a yeasty fermented smell means fermentation has set in.
Slight darkening is normal. But if it turns brownish-black and separates heavily, the quality is fading.
Shelf life at a glance
Opened or not, and where it is stored, decides the shelf life:
| State | Shelf life |
|---|---|
| Unopened, stored cool | 1–2 years |
| Opened, in the fridge | 1–6 months |
| Opened, at room temperature | a few weeks |
| Mold or fermentation | discard |
Store it right
The right storage keeps ketchup good for a long time:
Refrigerate after opening — the fridge keeps colour, flavour and texture best.
Keep the bottle clean — wipe the rim and cap now and then so mold cannot form there.
Seal it well — close the cap tightly so as little air as possible reaches the contents.
Portion cleanly — do not dip used utensils or fries into the bottle.
Common myths
A few stubborn half-truths surround ketchup:
Unopened, no — but opened, yes: refrigerated it stays fresh much longer, as the makers recommend.
No — unopened it is often good well past the date. Sugar and vinegar preserve it reliably.
Not necessarily — slight darkening is normal. Only mold or a fermented smell is a stop sign.
The dark crust at the bottle neck is dried, oxidised ketchup — harmless but unsightly. Just wipe it off. Tip — store the bottle upside down in the fridge door so the ketchup flows more easily and less air collects at the opening.