How to Dry Mushrooms at Home: Dehydrator and Oven Methods

Drying is one of the easiest ways to keep mushrooms. It turns a glut of shiitake from your logs or a basket of chanterelles into a jar of pantry flavour. It’s also easy to get wrong: mushrooms that are only partly dry can go mouldy in the jar, and drying won’t make an unsafe mushroom safe.

This guide walks through drying mushrooms at home in a dehydrator or an oven, step by step. It’s based on food preservation guidance from Oregon State University, North Dakota State University, the University of Arizona and the University of Illinois, plus a scientific review on mushrooms and vitamin D.

Safety first

Two rules come before anything else:

• Drying doesn’t remove toxins. North Dakota State University (NDSU) Extension warns that drying or cooking does not destroy the toxins in poisonous mushrooms.
• Only dry mushrooms you’re sure of. Oregon State University (OSU) Extension advises that, unless you’re an expert in mushroom identification, you should only preserve commercially sold mushrooms.

If you forage, have every mushroom confirmed by an experienced local identifier before you dry it. Our guide to wild vs cultivated mushrooms explains why this matters.

Which mushrooms dry well?

OSU’s Preserving Mushrooms guide suggests choosing mushrooms with closed caps and visible gills, and names button mushrooms, chanterelles and morels as good varieties for drying. Pick firm, fresh mushrooms. NDSU advises sorting out and discarding any produce with decay, bruises or mould before you start.

Step 1: Clean and slice

• Clean gently. OSU suggests cleaning mushrooms for drying with a soft brush or cloth, rinsing quickly, cutting away questionable parts and trimming woody stems.
• Slice evenly. Even slices dry at the same rate. NDSU suggests slicing tender stems ¼ inch (about 6 mm) thick, slicing large mushrooms and leaving small ones whole. OSU says mushrooms can be dried whole or halved at about ½ inch (about 13 mm).
• Optional pretreatment. NDSU doesn’t blanch mushrooms, but suggests dipping them for 10 minutes in a solution of 1 teaspoon of citric acid per quart (about a litre) of water, then draining. OSU’s drying method doesn’t include this step.

Step 2: Choose your drying method

Method	Temperature	What the guides say
Food dehydrator	120°F (49°C) in OSU’s mushroom guide; 125 to 140°F (52 to 60°C) in the University of Arizona’s vegetable guide	Arizona suggests 140°F if your dehydrator has no dial. Follow the manufacturer’s instructions
Oven	140 to 145°F (60 to 63°C), checked with a thermometer	NDSU says oven drying can take twice as long as a dehydrator, and isn’t safe if young children are around
Sun or air drying	Not controlled	The University of Illinois says sun-dried foods also need pasteurising to destroy insects or eggs that may be present

A dehydrator is the easiest and most consistent option. Spread slices in a single layer, with space between them, so air can move freely.

Oven drying, step by step

If you don’t have a dehydrator, NDSU describes how to use an oven:

1. Test your oven first. Set it to its lowest setting and put an oven-safe thermometer on the rack. It needs to hold 140 to 145°F (60 to 63°C).
2. Prop the door open. Leave the door open 2 to 6 inches (5 to 15 cm), with a fan nearby to move air.
3. Space the racks. Keep racks about 2 inches (5 cm) apart, with at least 3 inches (7.5 cm) clear at the top and bottom of the oven.
4. Don’t go hotter. NDSU warns that too much heat can cause “case hardening”, a crust that stops the inside from drying.

Many ovens can’t go this low. If yours can’t, a dehydrator is the safer choice. Whichever method you use, keep a note of the temperature, slice thickness and drying time for each batch. That way you can repeat what works and adjust what doesn’t, since every dehydrator and oven behaves a little differently.

Step 3: Dry until done

NDSU gives a drying time of 8 to 10 hours for mushrooms, but stresses that drying isn’t a precise process. Times depend on the equipment, how wet the mushrooms are, and the humidity of the air.

How do you know they’re done? The guides describe it slightly differently:

• OSU: dry mushrooms “until crisp or brittle”.
• NDSU: mushrooms should be “dry and leathery”.

Always test a few pieces after they’ve cooled, as NDSU advises. If you’re unsure, give them longer. The University of Illinois notes that dried vegetables are brittle or crisp at a moisture level of about 10%.

Step 4: Cool and check

The University of Arizona says to package dried vegetables only after they’ve cooled completely, because warm food releases moisture as it cools.

For dried fruit, the University of Illinois recommends a step called conditioning: pack the cooled food loosely in a closed jar, leave it at room temperature for 7 to 10 days, and check it daily for condensation. If moisture appears, it goes back in the dryer. The guidance is written for fruit, but a few days of daily checks is a sensible precaution for home-dried mushrooms too, especially thick pieces.

Step 5: Store

Storage tip	Source
Use clean, dry glass jars, ideally dark glass, or moisture- and vapour-proof freezer containers or bags	NDSU
Store in a cool, dry, dark place. About 60°F (16°C) is best, with 60 to 80°F (16 to 27°C) acceptable	University of Arizona
Label each container with the contents and the date	University of Arizona
Expect a shelf life of about 6 to 12 months for dried vegetables	NDSU (Arizona gives up to six months)
Store in the fridge or freezer to keep them longer	University of Arizona
Throw away anything that develops mould, off-odours or off-flavours	NDSU and University of Arizona

Our guide to fresh vs dried mushrooms covers how to tell when dried mushrooms have spoiled.

Rehydrating dried mushrooms

OSU suggests soaking dried mushrooms in boiling water “for a few minutes until softened”, then lifting them out with a slotted spoon. The soaking liquid is full of flavour. Strain it before adding it to a sauce or soup, and treat it as a perishable food.

A bonus: vitamin D from sunlight

Mushrooms can make vitamin D2 when exposed to ultraviolet light, including sunlight. A 2018 review by Cardwell and colleagues in the journal Nutrients pulls together the research:

• Sliced mushrooms produce more vitamin D2 than whole mushrooms from the same amount of UV exposure.
• In one German study, sliced mushrooms in midday summer sun reached 17.5 µg per 100 g fresh weight after 15 minutes, and 32.5 µg after 60 minutes.
• Results depend on the time of day, season, latitude, weather and exposure time.
• In one shiitake study, the amount of vitamin D2 produced by UV exposure fell as the mushrooms’ moisture content dropped.
• Vitamin D2 declines slowly in storage. Hot-air-dried button mushrooms kept dark and dry at 20°C fell from 14.3 to 9.3 µg per gram of dry matter over eight months.

If you’d like to try it, one option is to give fresh slices some sun before you dry them in your dehydrator or oven. The amount you get at home will vary a lot, so don’t rely on it as your main source of vitamin D.

Troubleshooting

The University of Arizona sums up the main enemies of dried food as “moisture, heat, air and light”. Most problems come back to one of them.

Problem	Likely cause	What to do
Crusty outside, soft inside	Case hardening from too much heat, as NDSU describes	Dry at a lower temperature, and check the oven with a thermometer
Drying takes much longer than expected	Thick slices, wet mushrooms or humid air, which NDSU lists as factors in drying time	Slice more evenly, avoid rinsing for long, and give them more time
Condensation inside the jar	Mushrooms packed warm or not fully dry	Return them to the dryer, then cool fully before packing
Mould or off smells in storage	Moisture getting in, or incomplete drying	Throw the batch away. Don’t try to rescue mouldy mushrooms
Insects in sun-dried mushrooms	Pests getting in while drying outdoors	Use a dehydrator or oven. Illinois notes that sun-dried foods need pasteurising

Keep it clean

Drying is food preparation, so normal kitchen hygiene applies. The University of Arizona advises washing your hands with soap and water for 20 seconds before and after handling food, and cleaning and air-drying your dehydrator and utensils before and after each use. Use a clean, dry jar for every batch.

What about freezing?

Freezing is the other main option. OSU says most varieties freeze well if they’re heat-treated first, and calls sautéing until almost done the preferred method for many varieties. Cool, pack, seal, label and freeze them. OSU also says only domestically grown button mushrooms should be canned at home.

Ideas for dried mushrooms

Dried chanterelles, morels and shiitake add depth to soups, risotto, stews and sauces. For more on cooking with two of these mushrooms, see our guides to chanterelles and shiitake. If you grow your own, our guide to growing shiitake on logs may give you more than you can eat fresh.

Sources and further reading

• Oehler, N. (rev. 2013). Preserving Mushrooms (SP 50-919). Oregon State University Extension Service
• Garden-Robinson, J. (rev. 2022). Drying Vegetables (FN1588). North Dakota State University Extension
• Wyatt, M., Wilson, H., Suzuki, A. and Hongu, N. (2019). Home Food Preservation: Drying Vegetables (AZ1802). University of Arizona Cooperative Extension
• Mellendorf, C. (2021). Fill Your Pantry: Drying Foods at Home. University of Illinois Extension
• Cardwell, G., Bornman, J. F., James, A. P. and Black, L. J. (2018). A review of mushrooms as a potential source of dietary vitamin D. Nutrients 10(10): 1498

Featured image: chanterelles by Ben Mitchell via iNaturalist (CC0 1.0). Inline photo by Allan Audsley via iNaturalist (CC0 1.0).