How to freeze and dry mushrooms: what to do and why

The harvest is home, and the first few hours decide everything. Mushrooms spoil quickly: they need to be eaten or preserved as soon as possible, and until then kept somewhere cool or in the fridge ¹. Below are two ways to keep them for a long time, freezing and drying. Each step comes with its reason, which makes it easier to avoid mistakes and not throw your stock away a month later.

One important condition: this is only about mushrooms you have already identified with certainty. This text cannot tell you whether a mushroom is edible. For dangerous species, see the section on poisonous mushrooms, and you can check conditions for your next outings on the map.

Only clean, fresh and healthy mushrooms go into preserving

Whichever method you choose, only clean, fresh and healthy mushrooms should be preserved ¹².

This matters especially for freezing. At a constant temperature of −18 °C or lower, the micro-organisms that spoil food and can cause illness do not die: the cold only stops them growing. Once the mushrooms thaw and warm up, the microbes multiply again, and it can end in food poisoning. A freezer preserves what you put into it, but fixes nothing ³.

Mushrooms are heated before freezing: steamed or in a frying pan

Both methods work, but steamed mushrooms keep for longer than those heated in fat.

Steaming time depends on how you have cut the mushrooms:

For the second method, heat the mushrooms in small batches in butter or margarine in an uncovered frying pan until almost cooked. After either method, cool the mushrooms quickly, either in the open air or by standing the pan in cold water. Let steamed mushrooms drain. Then pack the mushrooms into containers or bags, leaving a little space at the top, close them and put them in the freezer ⁴.

You need a four-star freezer

It is recommended to freeze food at −18 °C or lower. A three-star freezer also holds −18 °C, but it is only suitable for storing food that is already frozen, and then for up to three months. For freezing fresh mushrooms for the long term, use a four-star freezer ³.

Hot food should not go straight into the freezer: it harms the other food in there. So let the heated mushrooms finish cooling in the fridge first. Write on each pack what is inside and the date it was frozen ³.

Frozen mushrooms are best eaten within 8–12 months

This period relates to quality, not safety. If frozen correctly, food stays safe almost indefinitely, but over time it loses flavour and texture. If you want the best quality, go for a shorter period ³⁵.

Never thaw at room temperature

The most vulnerable moment comes after the freezer: between 5 and 65 °C microbes multiply fastest. Cook or eat thawed mushrooms as soon as possible. Do not refreeze them. There is one exception: if you have cooked them at a temperature above 70 °C for at least two minutes ³.

Dry at 60 °C, no hotter

Drying is simpler: mushrooms need neither heating nor blanching. The best temperature is 60 °C, and dehydrators are designed for exactly that. At a higher temperature the mushrooms cook rather than dry, and then more often go mouldy ⁶⁸.

In a dehydrator, mushrooms dry in 8–10 hours; the exact time depends on how moist they were and on the appliance itself. In an ordinary oven, drying can take up to twice as long, depending on how the air circulates in it ⁶.

Dry until brittle and put into airtight containers straight away

Finished mushrooms are brittle and snap easily. In this state they retain about a tenth of their moisture ⁶⁷.

Before packing, let the mushrooms cool completely. Warm mushrooms ‘sweat’, and that moisture can be enough for mould to take hold. Once they have cooled, pack them straight away: dried mushrooms easily absorb damp and attract insects. Clean, dry jars, plastic containers with tight lids or freezer bags will all do. Store them somewhere cool, dry and dark ⁷.

But even well-packed mushrooms can turn damp in storage, so check your stock from time to time. Glass jars are the most convenient: moisture on the sides is visible at once. If the mushrooms have gone mouldy, throw them away. If they have turned damp but have not spoiled, eat them straight away or dry them again and repack them ⁷.

Dried mushrooms keep for 4 months to 1 year

The period depends on temperature: the warmer the place, the faster the quality drops. In the cool, your stock lasts longer ⁶⁷.

Preserving will not make a poisonous mushroom safe

Neither drying, freezing nor cooking destroys the toxins of poisonous mushrooms. Some very dangerous toxins withstand heat ¹⁶. So preserving is no substitute for identifying a mushroom with certainty. If you feel ill after eating wild mushrooms, call 112.

Drying also concentrates whatever the mushroom has accumulated. Wild mushrooms draw heavy metals out of the soil, especially mercury, and its share rises in the dried product. So it is best not to eat dried mushrooms in large quantities ⁹.

In brief

• Preserve only clean, fresh and healthy mushrooms.
• Before freezing, heat the mushrooms: steam them (5, 3.5 or 3 minutes depending on the cut) or heat them in a frying pan until almost cooked. Then cool them and label the pack.
• Freeze in a four-star freezer at −18 °C or lower and store for 8–12 months.
• Do not thaw at room temperature, and do not refreeze unless cooked above 70 °C.
• Dry at 60 °C until brittle, cool completely and put into tightly closed jars in a cool, dry, dark place.
• Check the jars: throw away anything mouldy, and dry damp mushrooms again.

Checked against sources on 3 October 2026.