Two hours. That is the number that actually governs potato salad —
not the three or four days it keeps refrigerated. Two hours at room temperature and the
count starts again, badly.
Why two hours, and why potato salad specifically
It is not the mayonnaise. Commercial mayonnaise is acidic and fairly hostile to bacteria.
It is the cooked potato: moist, low in acid, handled a great deal, and served at exactly the
temperature bacteria prefer.
Which is why potato salad is the classic problem at picnics and buffets while the same
mayonnaise on a sandwich is not.
Below the line: kept cold throughout
Three to four days, and five for a vinegar-dressed version.
That is the number most people are looking for, and it holds only under this condition.
Above the line: it was out at a barbecue
Same day, and anything past two hours goes in the bin rather than back in the fridge.
Outdoors above 25 °C, halve it to one hour.
How to stay under the line
- Keep the bowl on ice outdoors, or bring out half and leave the rest
refrigerated. - Dress it late. Boiled, cut and refrigerated components keep their full
3–4 days undressed; combine a few hours before serving. - Cool the potatoes before dressing. Warm potato in mayonnaise starts the
clock while you are still making the salad.
What shortens it even under the line
Homemade mayonnaise — raw yolk and no preservatives means one to two days,
not four. Worth knowing before making a large bowl for a party.
Times, for reference
| State | How long |
|---|---|
| Mayonnaise-dressed, kept cold | 3–4 days |
| With homemade mayonnaise | 1–2 days |
| Vinegar-dressed | up to 5 days |
| Undressed components | 3–4 days |
| Left out at room temperature | 2 hours, then discard |
And do not freeze it
Mayonnaise splits irreversibly and
boiled potato turns
mealy. Of everything in this section, potato salad is the worst freezer candidate.
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