Rescues · TO BLANCH
Vegetables are olive green and limp.
Why it happens
Left too long. The same heat that brightens chlorophyll destroys it, and the transition is quick.
Recovering it
Over-blanched vegetables cannot regain colour or bite; they belong in a soup or a purée. Under-blanched is easy — back in for another twenty seconds. If the ice bath was skipped and things went soft, there is no fix, but the habit is cheap: set the bowl of iced water up before the pot goes on, not after.
The mechanism
Blanching does several unrelated jobs and it is worth knowing which one you are doing. It sets green colour: brief heat drives out the gas trapped between cell walls that dulls chlorophyll, so the green brightens — and prolonged heat then degrades that same chlorophyll to olive, which is why the window is short. It deactivates enzymes, particularly the ones responsible for off-flavours and texture loss in frozen vegetables, which is why blanching before freezing genuinely matters. It loosens skins on tomatoes, peaches and almonds by expanding the flesh just beneath and breaking the bond. And it removes harshness from bitter greens and raw onion. The ice bath is not optional in most of these — residual heat keeps cooking the vegetable for minutes, and without shocking, a perfectly blanched vegetable overcooks in the colander.
The full TO BLANCH lesson — how to tell, where to practise it, what it carries to.