Dried Mushrooms: The Complete Guide

A jar of dried mushrooms looks like very little: light, brittle pieces a good deal less handsome than they were in the forest. Warm water changes that. The pieces soften, their shape comes back, and the water turns amber or deep brown. One ingredient becomes two, the mushroom and a small quantity of remarkably flavorful broth. Drying turns a fragile, short-season food into something that keeps in a jar and can carry a risotto, a pot of beans or a pan sauce. The method is simple. The details decide whether dinner tastes deeply of mushroom or faintly of sand, and they live in three places: the back of the bag, the soaking bowl and the pan.

What drying does

A fresh mushroom is mostly water. When USDA's Nutrient Data Laboratory analyzed raw cultivated mushrooms, moisture ran from 87.7 grams per 100 grams in enoki to 92.2 grams in white button mushrooms. The Codex Alimentarius standard for dried edible fungi, the international reference, caps a properly dried mushroom at 12 percent water, 13 percent for dried shiitake and 6 percent for freeze-dried. Take nine-tenths of the weight away and what is left is the flavor, the aroma and the structure, packed into something that keeps in a jar.

Drying changes the mushroom as well as shrinking it. Texture goes first. A rehydrated chanterelle is softer and less springy than a fresh one, and dried porcini work best as flavor spread through a dish rather than as a steak of mushroom. What drying keeps is flavor. Dried porcini turn deep and savory, and candy caps, once dried, carry an intense maple fragrance.

How much fresh mushroom is in an ounce of dried

Dried mushroom prices look alarming until they are converted back into mushroom. An ounce of dried mushroom at the Codex ceiling of 12 percent water holds at least 0.88 ounce of dry matter. Fresh mushrooms at 87.7 to 92.2 percent water carry 7.8 to 12.3 percent dry matter. Divide one by the other and an ounce of dried mushroom is the dry matter of roughly 7.2 to 11.3 ounces of fresh. The table applies that range to common weights and to the Wine Forest jars on the shelf.

Two cautions. The moisture figures come from cultivated mushrooms, and the wild species in these jars were not measured. Wine Forest says an ounce of its dried yellow foot equals nearly a pound of fresh, above the top of the range, which fits a thin, wet mushroom dried well below the ceiling. A rehydrated mushroom also does not regain all its water, so the table describes how much fresh mushroom went into the jar, not what the soaked mushrooms will weigh. For four servings of pasta or risotto, half an ounce to an ounce is a sensible range. Start low, since a small amount of dried porcini flavors a whole pot.

The seven worth knowing

Choose by what gets cooked. One or two jars that suit the kitchen do more work than a collection too precious to open.

Porcini. The most versatile dried mushroom. Deep, woodsy, almost meaty, and a few slices change a tomato sauce, a ragù, a soup or a pan sauce. Soak, chop, cook with shallot or garlic in butter or olive oil, and add the strained soaking liquid to the same dish. Porcini suit beef, pork, polenta, beans, potatoes and pasta, and they are the mushroom in the dried porcini risotto, the clearest demonstration of what a good dried slice does. They also carry more law and more confusion than any other mushroom here, which is why the section on reading the bag is written around them.

Morels. Hollow and honeycombed. They rehydrate well and keep enough structure to leave whole, halve or stuff. Butter and cream are the classic partners; roast chicken, veal, eggs, asparagus and peas are equally good. Wine Forest dried morels (shop Wine Forest dried morels) are Morchella esculenta from Montana and Idaho, with a soak of 15 to 20 minutes per the producer, who advises rinsing the cavity well before stuffing. Morels must be thoroughly cooked, for reasons set out below.

Black trumpets. Thin, dark funnels with a flavor far bigger than their weight. They are good in a potato gratin, with eggs, cream and fish, or folded through pasta, and a cream sauce made with them tastes of something other than generic mushroom. Wine Forest black trumpets (shop Wine Forest black trumpets) soften in about five minutes; the producer advises washing the hollow tubes, slitting each one open after soaking and giving them a quick second soak, because grit hides inside.

Chanterelles. Firm and delicately fruity. Drying keeps the flavor more readily than the fresh texture, so rehydrated chanterelles do best cooked gently in liquid, in soups, cream sauces, braises and gravies, rather than in a quick dry sauté that expects the fresh mushroom back. Wine Forest chanterelles (shop Wine Forest chanterelles) can go in whole or chopped.

Mousserons, or fairy rings. Marasmius oreades, small and very light, with a flavor Wine Forest describes as much like porcini with a touch of hazelnut. A jar holds a great many individual caps, which stay visible in an omelet, a risotto or a sauce. They soak in about five minutes, and because they tend to grow in sandy soil the producer advises rinsing them two to three times. Wine Forest mousserons (shop Wine Forest mousserons) come from Bulgaria.

Yellow foot. The braising mushroom. In Wine Forest's words they become a melting, silky sauce at the bottom of the pan rather than chewy pieces. Use them with braised meat, beans, potatoes, kale or a restrained cream sauce, or grind them dry into a powder for soups, stews, gravies and sauces. Wine Forest yellow foot (shop Wine Forest yellow foot) are from Oregon and California.

Candy caps. The exception that rearranges the category. Lactarius rubidus from Northern California, with what the producer calls a haunting, intense maple flavor. They belong in crème brûlée, cookies, cakes, custards and hot cereal as naturally as in savory food with winter squash or glazed duck. Wine Forest candy caps (shop Wine Forest candy caps) can be soaked for 10 to 15 minutes, steeped in milk or cream, or ground dry straight into flour or sugar. Keep a grinder for them alone if the next batch of pepper should not smell of maple.

The six Wine Forest jars above sit together in the Wine Forest range.

Reading the bag

A bag of dried porcini can be the best value on the pantry shelf or the worst, and from the front the two look the same. Five lines on the back tell them apart.

The species. Porcini is a market name, not a species. The Codex standard asks that dried mushrooms be labeled with both the common and the scientific name of the species, and a careful packer prints Boletus edulis, or the related species of its group, in Latin. A bag that says only porcini, cèpes or king bolete has left out the one line that settles the question. The gap is real. In 2014 two mycologists at Kew bought a packet of dried Chinese porcini from a London grocer, sequenced fifteen pieces, and found three species that had never been scientifically described and none of which was Boletus edulis. They named them Boletus bainiugan, Boletus meiweiniuganjun and Boletus shiyong, and the accompanying announcement noted that around half of the porcini traded in Europe originates in China. A bag of wild mushroom mix works the same way: one that names its species in Latin can be judged, and one that says only mushrooms cannot.

The country. An Italian name, flag or packed in Italy line on dried porcini can describe where the bag was filled rather than where the mushrooms grew. Since April 2020 an EU rule has required that when a label gives or implies a country of origin and the primary ingredient comes from somewhere else, the label must say so or name the ingredient's origin, so an Italian bag may carry a line such as origine dei funghi: non UE. In the United States, imported goods must be marked with their country of origin for the ultimate purchaser, so a domestic bag of imported mushrooms should name that country somewhere on the pack.

Fungo di Borgotaro is Italy's EU protected geographical indication for porcini, covering four species of the edulis group, fresh or dried, from eight communes: Berceto, Borgo Val di Taro, Albareto, Compiano, Tornolo and Bedonia in the province of Parma, and Pontremoli and Zeri across the line in Massa Carrara. Its specification sets its own extra, speciali and commerciali grades for the dried product. Other place names on a porcini bag are the packer's description, not a protected origin.

The grade. Italian bags carry one more line. A 1998 ministerial decree requires the sale name of dried porcini in Italy to be accompanied by one of five qualifying terms, each defined by presentation, flesh color at packing, and two measured tolerances: the share by weight showing larval tunnels and the share with a darkened hymenium, the spongy underside of the cap.

Read across and the grade describes the mushroom before it was dried. Extra usually points to firm, young porcini sliced and dried before insects or age reached them. Commerciali tends to come from older or slower-dried material, and up to a quarter of the bag may show tunnels. Neither is a fraud. They are different raw materials at different prices, and the grade says which is inside. The decree also lets porcini from other EU countries use the qualifying terms of their own national law. Words such as grade A, first grade, premium or select appear in neither the Codex standard nor the Italian decree, and carry no tolerance behind them.

The floors beneath the grades. The Codex standard allows wild dried mushrooms up to 20 percent by weight of maggot damage, against 1 percent for cultivated ones, with mineral impurities such as sand capped at 2 percent and crushed pieces at 6 percent. The FDA's defect action level for dried mushrooms in the United States is an average of 20 or more maggots of any size, or 5 or more maggots 2 millimeters or longer, per 15 grams, or more than 10 percent of the mushrooms decomposed. These are the levels at which the agency acts. They explain why the pale, whole, tunnel-free slice costs what it does.

The cut and the color. Codex defines a sliced dried mushroom as cut 1 to 4 millimeters thick before drying, and separates whole, caps and sliced as label styles. Whole slices show every defect and are the easiest to judge. Pieces and powder hide them, and are correctly priced when sold as seasoning rather than as mushroom. Because the Italian grades are partly defined by flesh color, color is the grade at a glance: cream and pale tan points toward extra or speciali, uniformly dark brown toward commerciali. A clear window in the bag is there so that the buyer can look.

What to buy for which job

For a risotto, a ragù or a pan sauce where the mushroom is eaten as itself, buy sliced porcini in the extra or speciali grade, pale and whole, with the Latin on the back. For a stock, a bean pot or anything where the mushroom dissolves into liquid, commerciali or pieces do the same work for less, and the extra grade is money spent on a shape nobody sees. For a spring dish or a cream sauce that wants a whole mushroom on the plate, morels. For pasta, potatoes and eggs with a darker character, black trumpets. For braises, yellow foot. For baking, candy caps.

How to rehydrate them

Use a tall, narrow bowl, which concentrates settling grit at the bottom. Cover the mushrooms with tepid or warm water; Wine Forest recommends tepid water, and the Missouri Department of Conservation suggests warm. Use only enough water to submerge them, because a concentrated cup of broth is more useful than a quart of weak brown water. After about five minutes, swish them vigorously so any sand loosens and sinks. When the mushrooms bend easily with no hard center, lift them out by hand or with a slotted spoon. Pouring the bowl through a colander sends the settled grit straight back over them.

Treat the times as a minimum. Thick morels and large porcini slices can take longer, and the Missouri guidance allows 30 to 60 minutes in warm water. Stock or wine can stand in for water when the liquid is going into the finished dish. Water stays the most versatile, since it gives an unsalted broth that can be seasoned later.

The soaking liquid

The strained liquid is the second ingredient in the jar. Strain it through a coffee filter in a funnel or a very fine sieve, and stop pouring before the last gritty spoonful. It is then instant mushroom stock for risotto, soup, gravy, pan sauce, beans or braising liquid. If it smells unpleasant rather than cleanly earthy, discard it.

Cooking with them

Soaking softens a dried mushroom and leaves the cooking still to do. Once rehydrated, cook the mushrooms in fat, sauce or broth so their remaining structure softens and their flavor spreads through the dish.

With fresh mushrooms. One of the best uses. Brown fresh cremini, oyster or shiitake well for bulk and a juicy texture, add the rehydrated wild mushrooms once the fresh ones have given up their moisture, then deglaze with strained soaking liquid and reduce.

Pasta. Sweat shallot in butter or olive oil, add the chopped mushrooms and cook until tender, add a little soaking liquid and reduce it, then finish with cream, tomato, cheese or more butter and toss with the pasta and some of its cooking water. Porcini, black trumpets, morels and yellow foot all work.

Risotto. Combine the strained broth with the hot stock, add the chopped mushrooms during cooking, and keep a few good pieces for the top. Porcini give the classic version, as in the dried porcini risotto. Morels make a richer one, and mousserons leave small whole caps through the rice.

Soup and beans. Strain especially carefully for a clear soup. For puréed soups, simmer the mushrooms with potatoes, onions or beans and blend. Chanterelles and yellow foot suit creamy soups; black trumpets turn a pale soup dramatically dark. A spoon of mushroom garum (shop mushroom garum) at the end does a similar job in liquid form. The brothy beans with mushroom garum guide and the garum guide show how, and the umami guide puts both on the savory shelf.

Eggs. Cook the rehydrated mushrooms in butter first, then fold them into scrambled eggs, an omelet or a quiche. Morels and black trumpets are especially good here.

Powder. Grind clean, fully dry mushrooms in a spice grinder. The powder disappears into soups, gravies, compound butter, meatballs and rubs. Add a little, cook, taste, and add more; powder spreads flavor more thoroughly than pieces do.

Morels must be cooked

In March and April 2023, 51 people became ill after eating at a restaurant in Bozeman, Montana. Three were hospitalized, and two, both with chronic underlying medical conditions, died. The CDC's investigation linked the outbreak to morels, found higher odds of illness on a day the morels were served uncooked and cold-marinated than on a day they had been partially cooked, and concluded that morels should be cooked before eating. Soaking is not cooking. Rehydrate them, then sauté, simmer or roast until thoroughly cooked through.

How to store them, and when to let go

Humidity undoes drying. Keep dried mushrooms airtight, in a sealed glass jar or the closed original package, somewhere cool and dark. The Missouri Department of Conservation says that kept that way they last a very long time. The Codex standard asks packers for packaging that protects against humidity and for mushrooms packed loosely, so a bag with condensation inside or contents stuck together has failed at its main job. Keep the jar away from the stove, the kettle and the dishwasher. The mushrooms should stay brittle, never flexible, damp or sticky. The pantry storage guide covers the rest of the shelf.

Dried mushrooms go bad in two ways. The first is spoilage: discard any that show mold, insects, unexplained moisture or a rotten, damp smell. The second is fading. A good dried mushroom smells sweet, meaty and earthy when the jar opens. Over time the aroma fades and the color dulls, and a mushroom that has lost its smell has lost the reason to keep it. Buy the youngest bag with the furthest date, in an amount that will get cooked rather than kept as decoration.

Loose ends

Dried against fresh. Different rather than lesser: less texture, more concentrated flavor, and a broth fresh mushrooms do not give. Grit. Not a sign of a bad batch. Codex allows up to 2 percent mineral impurities such as sand in wild dried mushrooms, and the soak-and-lift method is there to remove it. Wild mushroom mix. A bargain only if the species are named. The soaking water. It goes in anything savory with liquid, once strained. Hot water or tepid. Both work; tepid is the producer's recommendation, and the Missouri Department of Conservation suggests warm. Candy caps. They do not need soaking, and the producer suggests grinding them straight into sugar or flour.

Visitors to the shop at 263 Josephine Street in Cherry Creek, Denver, can ask staff questions about any of these, and products ship across the continental U.S. from theambrosianpantry.com.

Sources & Further Reading

• Codex Alimentarius: Standard for Dried Edible Fungi, CXS 39-1981
• Italian Ministerial Decree of 9 October 1998: qualifying terms for dried porcini
• Consorzio Fungo di Borgotaro: IGP specification
• Dentinger and Suz, PeerJ 2014: undescribed species of porcini in a commercial packet
• EurekAlert: announcement of the Kew porcini study
• Commission Implementing Regulation (EU) 2018/775: origin of the primary ingredient
• 19 U.S.C. 1304: country of origin marking of imported articles
• FDA: Food Defect Levels Handbook
• USDA ARS Nutrient Data Laboratory: nutrient content of selected mushrooms
• CDC MMWR: Outbreak Linked to Morel Mushroom Exposure, Montana, 2023
• Missouri Department of Conservation: preserving mushrooms for later use
• Wine Forest: rehydrating dried mushrooms
• Wine Forest: dried morels
• Wine Forest: dried black trumpets
• Wine Forest: dried mousserons
• Wine Forest: dried yellow foot
• Wine Forest: dried candy caps