Potato is the clearest case of a single ingredient behaving in opposite ways depending on
what has been done to it. Raw it fails; part-fried it comes out better than fresh.
Taken by state:
Raw — no
Two things at once. It is mostly water, so ice crystals rupture the cells and it thaws to
mush. And the enzymes keep converting starch to sugar in the cold — which is why thawed raw
potato is not just watery but noticeably sweet, and browns far too fast
in a pan.
Blanched — yes, up to 6 months
Three to five minutes in boiling water deactivates the enzymes and firms the surface,
which solves both problems.
Peel and cut as you intend to use them, boil 3 minutes (chips) or 5 (large chunks),
straight into iced water, dry thoroughly, freeze in a single layer.
Cook from frozen; never thaw.
Part-fried chips — yes, and better than fresh
Same principle, with frying instead of blanching. Fry until pale, not golden,
cool completely, freeze. The second fry happens from frozen and gives a crisper result
than frying once ever does — which is precisely how the commercial ones are made.
Mashed — yes, up to 2 months
Better than you would expect, because mash already contains butter and milk,
and fat protects the structure from ice crystals.
Freeze flat in portion bags, reheat gently with a splash of hot milk stirred through.
Boiled whole — not worth it
Watery and crumbling. Only as part of a finished dish, if at all.
In soups and stews — leave it out
Everything else in the pot freezes cleanly; the potato comes back mealy.
Cook without it and add it when reheating, the same rule that applies to
borscht.
See also:
How long do peeled potatoes last in the fridge ·
Can you freeze carrots ·
How long does potato salad last in the fridge ·
Why fried potatoes are not crispy