Two minutes. That is how long broccoli spends in boiling water before it
goes into the freezer, and it is the difference between twelve months and two.
Cauliflower wants three.
What those two minutes do
Brassicas are full of enzymes and sulphur compounds. Freezing slows them but does not stop
them, and over a couple of months they get on with the job anyway — the florets yellow and
develop a bitter edge and a strong cabbage smell.
Two minutes of boiling water deactivates those enzymes permanently.
Nothing else in the process comes close in effect.
What happens with less
Under-blanched florets keep some enzyme activity, and you get the yellowing on a slower
schedule — four or five months rather than two. Better than nothing, worse than the full two
minutes.
What happens with more
Past about four minutes the florets are cooked rather than blanched. They come out of the
freezer soft and fall apart in the pan. The window is genuinely narrow.
The step that decides whether it worked
Iced water, for the same length of time. Skip it and the florets carry on cooking from
their own heat — you get the over-blanched result while thinking you did it right.
The rest of the method
- Cut into florets of even size, so they blanch evenly.
- Soak 20 minutes in salted water — a tablespoon per litre — to drive out
insects hiding inside. - Blanch: three minutes for both. A spoonful of lemon juice for cauliflower,
which greys readily. - Iced water, same duration.
- Dry thoroughly. Wet florets freeze into one block.
- Freeze in a single layer, then bag.
Do not cover the pan while blanching — a lid traps the sulphur compounds that cause both
the smell and the discolouration.
Afterwards
Cook from frozen, and shorter: broccoli needs 3–5 minutes, cauliflower 5–7.
Freeze the stalks too, sliced into coins — they are sweeter than the florets.
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Can you freeze zucchini ·
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