How do I blanch vegetables and why would I?
A brief boil followed by iced water, used to set colour, prepare vegetables ahead and get them ready for freezing.
- Difficulty
- beginner
- Time
- 15 min
- Read
- 2 min
Short answer
Boil briefly in heavily salted water, then plunge straight into iced water to stop the cooking. It sets the colour, halts the enzymes that spoil frozen vegetables, and lets you cook ahead and reheat later.
Blanching solves three problems at once: it fixes bright colour, it stops the enzyme activity that makes frozen vegetables deteriorate, and it lets you cook green vegetables in advance and finish them at the last moment.
What you'll need
- Large pan
- Bowl of iced water
- Salt
- Slotted spoon (optional)
Step by step
- Prepare the iced water before you start.A bowl of water with plenty of ice in it. Without it ready, the vegetables keep cooking and the whole point is lost.
- Bring a large pan of heavily salted water to a rolling boil.Salt like pasta water. Plenty of water so the temperature does not crash when the vegetables go in.
- Add vegetables in batches and time them.Beans and broccoli 2-3 minutes, peas 1, carrots 3-4, leafy greens 30 seconds. They should be bright and still firm.
- Lift them straight into the iced water.Immediately. This is what stops the cooking and locks the colour. Draining and leaving them in a colander does not.
- Leave them until completely cold, then drain well.Cold all the way through, then dried properly. Wet vegetables freeze into a block and reheat badly.
- For freezing, spread on a tray and freeze before bagging.It stops them freezing into one lump so you can take out what you need.
- To serve, reheat briefly in butter or a hot pan.One or two minutes. They are already cooked; you are only warming them and adding flavour.
Tips
- Blanching before freezing is not optional for most vegetables — unblanched ones develop off-flavours and mushy texture within a couple of months.
- Blanching also loosens skins on tomatoes, peaches and almonds. Thirty seconds and the skin slips off.
- For a dinner party, blanch all the green vegetables in the afternoon and reheat in butter at the last minute. It removes the most time-critical job.
Common mistakes
- Not preparing the iced water in advance — The vegetables keep cooking on their residual heat and lose both colour and texture.
- Blanching in unsalted water — Salt seasons the vegetables and helps preserve the colour. Unsalted blanching gives bland, duller results.
- Freezing vegetables without blanching — Enzymes stay active and cause off-flavours and soft texture within a month or two of freezing.
Questions people ask
What does blanching do?
A brief boil followed by iced water sets the colour, stops the enzymes that spoil frozen vegetables, and part-cooks them so they can be finished quickly later.
Do I have to blanch vegetables before freezing?
For most vegetables, yes. Without it, enzyme activity continues in the freezer and causes off-flavours and mushy texture within a couple of months.