Should I wash mushrooms or just brush them?
Wash them. The idea that mushrooms absorb water like sponges does not survive testing — what matters is drying them before they hit the pan.
- Difficulty
- beginner
- Time
- 5 min
- Read
- 3 min
Short answer
Rinse them quickly in cold water and dry them well. A mushroom is already about ninety per cent water and takes on only a tiny amount more in a brief rinse — far less than it releases when cooked. The genuine rule is that a wet surface will not brown, so drain and pat them dry, and never let them sit soaking.
The don't-wash-mushrooms rule is one of the most persistently repeated pieces of kitchen advice and one of the least supported. Weighed before and after a rinse, mushrooms take on a small fraction of their own weight — a matter of a few grams across a punnet — which is trivial next to the liquid they give up in a pan.
Step by step
- Rinse them briefly in a colander under cold water.Tip the whole punnet in, run cold water over, agitate with your hands for ten or fifteen seconds, and drain. That removes the growing compost, which is what you are actually washing off.
- Do not let them sit in water.A brief rinse is different from a soak. Left submerged for several minutes they do take up meaningful water, and gilled mushrooms hold it in the gills where it is hard to get out.
- Dry them properly.Spread on a clean tea towel or kitchen paper and pat. This is the step that actually matters — surface water hits the pan, turns to steam, and stops the mushroom browning until it has all gone. Give them a few minutes if you have them.
- Brush instead only where it genuinely helps.Very delicate wild mushrooms — morels excepted, which need proper cleaning — and anything you are going to slice raw for a salad. A soft brush or a damp cloth is fine there. For the button, chestnut and portobello mushrooms most people buy, rinsing is easier and better.
- Deal with wild and foraged mushrooms differently.Grit and insects in wild mushrooms often need a proper wash and sometimes a soak in salted water. Morels in particular must be cleaned thoroughly, because their honeycomb structure traps grit and small creatures. Dry them well afterwards.
- Cook them in a hot, uncrowded pan regardless.Mushrooms release a lot of their own water whatever you did beforehand. High heat, plenty of space and patience — they will release liquid, that liquid will boil off, and only then will they brown. Salt at the end, because salt pulls the water out sooner.
Tips
- Peeling mushrooms is unnecessary and wasteful. Trim the very end of the stalk and use the rest.
- Store them in a paper bag in the fridge rather than the plastic punnet with its film on — trapped moisture makes them slimy far faster than any washing does.
- Dried mushrooms are a different job entirely: soak them, and keep the strained soaking liquid, which is one of the most useful savoury ingredients you can get for free.
- If mushrooms have gone slimy or smell sour, wash all you like — they are past it.
Common mistakes
- Wiping each mushroom individually with kitchen paper — It takes ten times as long, removes less compost, and achieves nothing a fifteen-second rinse does not.
- Washing them hours in advance — Damp mushrooms deteriorate quickly. Wash them just before cooking.
- Crowding the pan and blaming the washing — A pan packed with mushrooms stews no matter how dry they started. Cook in batches over high heat.
Questions people ask
Do mushrooms really absorb water like sponges?
No. The structure is mostly water already, held in cells, and there is little capacity for more. Careful weighing shows a brief rinse adds only a small percentage of the mushroom's weight, most of which is on the surface and dries off.
What about the compost they grow in?
It is pasteurised growing medium rather than soil, and it is not harmful — but it is gritty and there is no reason to eat it. Rinsing takes it off.