How do I use dried mushrooms properly?

The soak, the soaking liquid that is the real prize, and the grit that ruins a dish if you pour it all in.

Difficulty: beginner
Time: 30 min
Read: 3 min

Short answer

Soak them in hot water for 20 to 30 minutes, then lift them out rather than pouring — the grit sinks. Strain the soaking liquid and use it, because that is where most of the flavour has gone.

Dried mushrooms are one of the most concentrated savoury ingredients available and they keep for years. The mistake almost everyone makes is treating the soaking water as a by-product rather than the point.

Step by step

Rinse them briefly first.A quick rinse under cold water shifts the loose grit before soaking. It does not lose meaningful flavour and saves a lot of straining later.
Soak in hot, not boiling, water.Just off the boil, enough to cover, for 20 to 30 minutes. Boiling water can make them slightly rubbery; cold water works but takes an hour or more.
Weigh them down.A small plate or saucer on top keeps them submerged. Floating mushrooms rehydrate unevenly.
Lift them out, never pour.Grit sinks to the bottom of the bowl. Lifting the mushrooms out with your fingers or a slotted spoon leaves the sediment behind.
Strain the liquid through muslin or paper.A coffee filter, muslin or kitchen paper in a sieve. Leave the last tablespoon in the bowl regardless.
Use the liquid as stock.This is the main reason to buy dried mushrooms. It goes into risotto, stew, gravy, ragù and soup, and it carries more savoury depth than most stock cubes.
Squeeze the mushrooms and chop them.Squeeze the excess liquid back into the bowl, then chop. Rehydrated mushrooms are chewier than fresh and are better chopped small.
Combine them with fresh mushrooms.A small handful of dried porcini added to a pan of ordinary chestnut mushrooms transforms the dish, which is the usual professional trick.
Know the varieties.Porcini for depth and meatiness, shiitake for savoury intensity, morels for a distinctive earthy flavour, mixed wild for general use. Porcini is the most useful single purchase.
Store them airtight and dark.They keep two years or more in a sealed jar in a cupboard, and can be ground to a powder that seasons almost anything.

Tips

The soaking liquid is the ingredient. Never pour it away.
Lift the mushrooms out; do not tip the bowl. Grit sinks.
Ground dried mushroom powder is one of the most useful things in a store cupboard.

Common mistakes

Throwing the soaking liquid away — A large part of the flavour leaves the mushroom and enters the water during the soak. Discarding it means eating the chewy remains and pouring the best part down the sink.
Pouring the whole bowl into the pan — Dried mushrooms carry fine grit and sand that has settled at the bottom, and pouring puts all of it into the dish. Nothing removes grit once it is in a risotto.

If it doesn't work

Gritty dish

Cause: Soaking liquid poured in unstrained — Fix: Strain through muslin or a coffee filter, and always leave the last tablespoon behind.

Mushrooms still tough

Cause: Not soaked long enough — Fix: Give them another twenty minutes, or simmer them briefly in their liquid.

Flavour weak

Cause: Liquid discarded — Fix: Use the soaking liquid in the dish — it carries most of the flavour.

Rubbery texture

Cause: Boiling water, or over-soaked — Fix: Use water just off the boil and 20 to 30 minutes.

Bitter taste

Cause: Old or poor-quality mushrooms — Fix: Check the packet date. Dried mushrooms keep well but not indefinitely.

Questions people ask

Can I use the soaking liquid instead of stock?

Yes, and it is often better. Mushroom soaking liquid is intensely savoury and works in risotto, gravy, stews and soups. Dilute it if it tastes too strong, and always strain it.

Are dried mushrooms as good as fresh?

They are different rather than worse. Drying concentrates the savoury compounds, so dried porcini has far more depth than fresh mushrooms, but the texture is chewier. Using both together gives the best of each.