Hold on to your hats, it’s mushroom season! This time of year there is a small window in late Autumn/early Winter which sees local foragers heading out to the forest in the hopes of a bounty of wild mushrooms. While I’m not much of a forager (farm shops and local markets are more my thing!) occasionally a friend of mine drops around a basket of mushrooms after a day out in the forest. However, the majority of the mushrooms that I dehydrate are purchased from our local grocery store or farmers’ market. I love to stock up and dehydrate when they are in season or there is a glut at the grocer. Or sometimes, I just overestimate how many I’ll need during the week and buy too many. Either way, drying mushrooms is the way to go when you have a bit of a bounty. So, here’s the how, the why, and all the nitty gritty on dehydrating mushrooms in a dehydrator.

Dehydrated mushrooms. in small bowls on a wooden bench. A small wooden handled knife sits beside. — Dehydrated shiitake, brown and saffron milk cap mushrooms

Now, if you’ve been around here before you may know that I’m a huge fan of dehydrating. Especially when we have a glut of something from the garden. In an average year, I dehydrate figs, a variety of citrus, garlic, and excess herbs to get us through winter as well as any leftover fruit that doesn’t get turned into jam or chutneys.

A few of my favorite ways to use dried mushrooms are…

In a soup or stew. A few dried mushrooms are one of the easiest ways to impart a deep, rich flavor to a slow-cooked dinner.
Make a salt rub with a little mushroom powder mixed with some sea salt flakes. It’s great for seasoning BBQ meats and adding a little mushroom flavor!
I love to use dried mushrooms to lift truffle dishes. Think truffle risotto or truffle mac and cheese. Both come alive with a few dried porcini mushrooms or some porcini powder.
Rehydrate and add shiitake mushrooms to your next stir fry.
Add some rehydrated mushrooms to a pasta like this boscaiola recipe.

To prepare your mushrooms

To clean store-bought mushrooms, they generally only need a wipe-over with a damp cloth to remove any debris. Depending on the mushroom type, I either leave small mushrooms whole or slice large mushrooms for dehydration.

To clean foraged mushrooms… Depending on the mushroom they might only need a trim and quick clean. If in doubt, I follow Not Quite Nigella’s rule of dunking the mushrooms in 1 part white vinegar to 6 parts water. Dry the mushrooms thoroughly, and slice them, before cooking with them or dehydrating. I don’t tend to dehydrate many foraged mushrooms that I’ve had to wash as they take a bit to dry out again before dehydrating. And to be honest, they never last long enough to get around to it!

Here’s what you need to get started

Fresh Mushrooms – I have used sliced brown mushrooms and shiitake mushrooms in this instance, however, you are only limited by the types of mushrooms that you can get your hands on in your area. Last year I was gifted a basket of saffron milk caps, so we ate some and popped the rest in the dehydrator for later!
A food dehydrator. Mine is the Fowler’s food dehydrator. I’ve had it for years and I love it!
Glass airtight containers or Mason Jars for storage.

Cooks notes

Make sure you use only the freshest and best produce when dehydrating. Like making jams, using older, bruised produce does not make great preserves. The same goes for anything that feels slimy. You can’t bring them back, it’s just best to discard them and move on.

How to dehydrate mushrooms

The first step is always to clean mushrooms with either a piece of damp paper towel or a mushroom brush. Either leave the whole or slice thinly. If you are slicing a really large batch of mushrooms, a food processor fitted with a 2mm slicing disc will slice them in seconds.
Lay the mushrooms flat in a single layer on dehydrator trays. Be sure to space them out so they are not touching each other.
Turn the dehydrator on to the dried fruit setting (52 degrees celsius) and leave to dry for up to 4-10 hours depending on the mushroom type and size.
Once cool, place mushrooms in an airtight container and be sure to mark with the date of drying.

Sliced brown mushrooms on a dehydrator tray before drying.

Dehydrated mushrooms slices in a round dehydrator rack.

Are they done?

It really depends on the type of mushroom and its size as to what it feels like when it’s fully dried and cooled. However, my rule of thumb is that they should feel hard and kind of brittle, like you could snap them in half. If they are at all bendy or squishy, they need to be dried for longer. These brown mushrooms were dehydrated for 8 hours.

Do I need a dehydrator?

I use my dehydrator quite a bit, but if you don’t have one, then no, you don’t need one. It just makes the process easier. Most mushrooms can be preserved by air drying them over a few days or weeks. The drying process is quite easy and very similar to drying herbs. Just thread the whole mushrooms onto a piece of string like you would a beaded necklace. Then hang the string in a warm place out of direct light until they are fully dried and will snap if you bend them.

A grey bench scattered with dried shiitake mushrooms — Dehydrated shiitake mushrooms

How to store dehydrated mushrooms for future use

Glass jars are my go-to way to store dried mushrooms for long-term storage. Alternatively, an airtight container will also work too. Store them in a dark place away from any direct sunlight and your dehydrated mushrooms will last for months, if not years. For the first month, I always like to keep an eye on them and twice a week, check for any signs of mold or condensation. this is a clear sign that there is moisture remaining in the mushrooms. If there is, (and providing there is no mold), pop them back into the dehydrator and dry the mushrooms for a further few hours.

If you live in an area with high humidity, a silica gel satchel popped into the container before sealing might be a good idea to absorb excess moisture.

Let’s take this up a notch and grind up those mushrooms!

Mushroom powder is a total flavor bomb in your slow cooking and can be added to so many dishes. Think of enhanced deep, mushroomy flavor without heaps of chunky mushrooms. Porcini powder is my go-to for adding more depth (or a subtle umami flavor) to a dish. A teaspoon or two can instantly change a stew from “oh-no” to ‘woah” in terms of taste.
The best way to grind up a small amount of mushroom powder for a dish is with a handheld spice grinder. It’s like a mortar and pestle but it traps the spices (or in this case mushroom slices) under the pestle and you twist it back and forth until your mushrooms grind into a fine powder. Like spices, grind little and often is my motto. You’ll get a much better flavor instead of grinding up large amounts to use over a long period of time. If you do make a larger batch, a high-speed blender will be your best friend and save your wrists!

A cast iron spice grinder with ground up porcini slices in it. Some whole porcini slices sit beside. — Dried porcini mushrooms ground up in a spice grinder.

Want to rehydrate mushrooms?

Here’s how. Rehydrating mushrooms is super simple. All you need is a small bowl with a little warm water. Pop the dried mushrooms in it and leave for at least 30 minutes to reconstitute them. Depending on what you are cooking, I will sometimes add a bit of warm water into the dish along with the newly rehydrated mushrooms for a bit of extra flavor.

Here are a few mushroom recipes you might like