How to store fresh mushrooms, and how long each kind lasts

TL;DR

• Paper bag, fridge, don't wash. Every university guide we found says the same thing. Home-grown mushrooms rarely need more than a brush before cooking.
• Not sealed plastic. Water condenses inside, the mushrooms run out of oxygen and go slimy.
• About a week in the fridge for blue oyster, shiitake and button mushrooms; king oyster and enoki last longer, lion's mane about a week. Not on the counter: at room temperature they visibly age within a day and are done in 1 to 3.
• Pink oysters are the exception: a day or two at best. Nobody has tested why. The best guess is that they're a tropical mushroom and the fridge hurts them.
• Harvesting on time helps. Mushrooms keep maturing after harvest, and in every grow we filmed this year we picked after the spores were already flying.
• To keep them longer, sauté and freeze, dry or freeze-dry them, then store dried ones airtight, cool and dark. Home pickling and canning recipes have only been tested on button mushrooms.

I picked a cluster of pink oysters one evening and left it in a bowl on the counter, planning to cook it the next day. By morning it smelled faintly of fish. The ones I'd put in the fridge didn't smell, but they'd gone limp and dull. My working rule since has been that pinks are good for about a day, sometimes less.

So I went looking for whether that's just me. This post is what the research says about storing fresh mushrooms, species by species, with every claim linked to its source. Where the research is thin, and for pinks it's very thin, I've said so. Our own grow data covers what happens before harvest, not after.

How should you store fresh mushrooms?

Keep them unwashed in a paper bag in the fridge. Penn State puts it simply: "When loose mushrooms are stored out of a paper bag, they can dry out; if they are stored in a plastic bag, moisture can collect on the mushrooms and spoil them" (Penn State). The University of Missouri adds: "Avoid airtight containers that can collect moisture and cause the mushrooms to spoil faster. Do not store at room temperature" (Missouri). You'll also see advice to wrap them in a paper towel first. No university guide says that, but two shiitake growers in Cornell's guide line their storage pans with paper towel "to control moisture" and change it if they hold mushrooms a week or more (Cornell). It does no harm, and it helps if your mushrooms are damp.

• Don't wash or rinse them. Washing raises the water content, which "makes them more prone to the development of microorganisms and browning" (Castellanos-Reyes et al. 2021). Home-grown mushrooms come off clean substrate, so all they need is a soft brush or a wipe with a damp paper towel right before cooking (Missouri). Some guides allow a very quick rinse for gritty store-bought mushrooms; we never do it.
• Cool them fast. The USDA's storage handbook says mushrooms should be cooled "immediately after harvest" (USDA Agriculture Handbook 66, p. 415). For shiitake, Ohio State recommends slatted baskets or crates so they cool quickly, and warns that "frost-free refrigerators tend to dry mushrooms excessively" (Ohio State).
• Don't pile them up or squeeze them. Ohio State says to fill containers no more than 4 to 6 inches deep and to touch only the stems when picking, because "bruises on the caps and gills will discolor rapidly" (Ohio State). One study found that 10 seconds of rough handling did as much damage as 7 days at 5 °C (41 °F; Burton & Noble 1993, cited in Dawadi et al. 2022).
• Keep them away from strong smells. Mushrooms absorb odours, from green onions for example (UC Davis). The USDA handbook also says to keep them away from ripening fruit because ethylene browns the caps, though UC Davis found ethylene has no significant effect on button mushrooms. Keeping them apart costs nothing either way.

The commercial standard is close to freezing, 0 to 2 °C (32 to 36 °F) at 90 to 98 % relative humidity (USDA AH-66, p. 54). A home fridge runs a little warmer, around 3 to 4 °C (37 to 39 °F), which is one reason home shelf lives are shorter than the ones in trade tables.

Why do mushrooms go slimy in plastic?

Because mushrooms keep breathing after they're picked, and fast. The USDA handbook puts mushrooms in its highest respiration class, alongside asparagus and broccoli (USDA AH-66, p. 68). In a sealed bag that does two things:

• Water condenses on the inside of the bag and on the caps, which "promotes decomposition, microbial growth, and browning of the product surface" (Castellanos-Reyes et al. 2021).
• The oxygen runs out. Below about 2 % oxygen, mushrooms switch to anaerobic respiration, which opens the door to anaerobic bacteria (same source).

The second one matters for safety, not just texture. In a 1975 lab study, mushrooms deliberately contaminated with botulism spores and sealed in plastic film produced toxin by day 3 or 4 at 20 °C (68 °F), "when the mushrooms still appear edible". None did at 4 °C (39 °F) (Sugiyama & Yang 1975). A follow-up found that a single 1/8-inch (3 mm) hole in the film was enough to prevent it (Sugiyama & Rutledge 1978). Those were worst-case lab tests, not a measure of how often it happens. But it's why commercial packs have perforated film, and why "sealed and warm" is the one combination to avoid.

Airtight is worse than open even before safety comes into it: oyster mushrooms in vacuum-sealed bags at room temperature lasted 0.9 to 2.2 days less than ones in bags left partly open (Abou Fayssal et al. 2023).

If you've bought mushrooms in a vented clamshell, the original pack is fine. Penn State and Health Canada both say you can leave them in it (Penn State; Health Canada).

How long do fresh mushrooms last?

About a week in the fridge for most cultivated mushrooms. At room temperature they're done in 1 to 3 days, and that's how fast they spoil, not a way to keep them: Missouri says "Do not store at room temperature", and one day is enough to open, brown and soften the caps (more on that below). A 2021 review puts button, oyster and shiitake at "one to three days at ambient temperature (20–25 °C)" (68 to 77 °F) and five to seven days at 4 °C (39 °F), with shiitake shorter at three to five (Castellanos-Reyes et al. 2021).

How long fresh mushrooms keep, by species. Days until quality drops, from published studies and university guides. Fridge means about 4 °C (39 °F); room temperature about 20 to 25 °C (68 to 77 °F). The ranges are wide because the studies used different packaging and starting quality.

Two things to know about this table. First, sources disagree more than you'd expect: Ohio State gives button mushrooms 17 to 20 days at 0 °C (32 °F), two to three times what UC Davis and the USDA handbook give (Ohio State). Second, there's nothing at all for chestnut, black pearl or fresh reishi. Reishi is dried in practice, and keeps "several months" that way (Dawadi et al. 2022).

Why do oysters keep worse than buttons? They breathe faster. At 0 °C (32 °F), a blue oyster gives off roughly twice the CO2 of a button mushroom (Villaescusa & Gil 2003 against USDA AH-66; the comparison across the two studies is mine).

Why don't pink oysters keep?

Nobody has measured it, but the likeliest reason is that pinks are tropical and the fridge is too cold for them.

The short shelf life itself is well backed. Ohio State's mycology program gives pink oyster "a limited shelf life of under 3 days" (Ohio State). Grower sources are harsher: 1 to 2 days from one supplier (Rootlab), and "only about a day, quickly developing an unpleasant amine or urine-like odor after that time" in Wikipedia's entry, which cites a produce wholesaler (Wikipedia). That matches my counter-top fish smell.

The why is where the research runs out. I couldn't find a single published storage study of fresh pink oysters: no respiration rate, no fridge-versus-cool trial, nothing. What exists is evidence from their tropical relatives:

• A Thai trial of four oyster types found that the tropical "Abalone" oyster showed "chilling injury symptoms" at 4 °C (39 °F) and kept best at 10 °C (50 °F), where it lasted 18 days. The other three kept best at 4 °C (39 °F) (Jitareerat et al. 2018).
• Straw mushroom, the best-studied tropical mushroom, "exhibits rapid softening and liquefaction under conventional refrigeration conditions (0–4 °C)", that is 32 to 39 °F (Yang et al. 2026) and is stored at about 15 °C (59 °F) instead (Zha et al. 2022).
• Pinks fruit at 24 to 32 °C (75 to 90 °F) (Ohio State), much warmer than blue oysters, which puts them with those tropical species.
• Growing warm shortens shelf life even in blue oysters. Ones grown at 13 °C (55 °F) kept 24 days at 4 °C (39 °F), against 18 days for ones grown at 16 °C (61 °F) (Lee et al. 2011). Pinks are always grown warm.

Our own logbook agrees that pinks run fast. Across our blocks, pinks reached their first harvest a median 10.9 days after we moved them to fruiting (8 blocks), against 14.9 days for blue oysters (12 blocks). That's a different measure from shelf life, but it fits a mushroom that does everything quickly.

So my advice is: eat pinks the day you pick them. If you have to hold them overnight, a cool spot around 10 to 15 °C (50 to 59 °F), like a cool basement or a wine fridge, may beat the main fridge, but that's an inference from related mushrooms, not something anyone has tested on pinks. If you can't use them in a day, sauté and freeze them, or dry them. Pink oyster is one of the few specialty mushrooms with a published drying study (Siti-Nuramira et al. 2022).

Does when you harvest change how long mushrooms keep?

Yes, for the mushrooms anyone has studied, because mushrooms keep maturing after they're picked. UC Davis says "Mushrooms will continue to develop after harvest", with caps bending upward and veils opening (UC Davis). One day at room temperature is enough to open the caps, brown them and soften them (Castellanos-Reyes et al. 2021). A mushroom picked late starts that clock further along.

• Shiitake: Ohio State says pick at 50 to 75 % open, and that a fully open cap "can lead to reduced shelf life" (Ohio State).
• Button mushrooms: the one study that measured it found that picking at a medium cap size (3 to 4 cm, about 1¼ to 1½ inches) delayed the mushrooms' respiration peak by about 3 days compared with smaller or larger caps. The biggest caps gave the most yield but kept the worst (Wang et al. 2012).
• Oysters: no study links harvest stage to shelf life. Growers say picking pinks with the edges still curled down "doubles" their shelf life (Rootlab), but there's no data behind the number.

Our chamber's air sensor can tell when a mushroom starts dropping spores (how that works). In all 9 harvests we filmed this year, across 5 species, we picked after that point: a median 41 hours after, and never less than 23, even when the mushrooms looked right. Our two pink oyster blocks show the spread: one picked 2.6 hours after its cap edges lifted, the other 23 hours after, with nearly three times the spores in the air. That's the one my notes say I waited too long on.

What those stages look like is in our harvest guide.

Should you stop misting before you harvest?

Probably, though no one has put a number on it. Penn State's guide to bacterial blotch says the spots show up "wherever mushroom caps remain wet for a period of 4 to 6 hours or longer", and that blotch can appear "even on harvested refrigerated mushrooms or mushrooms over-wrapped with a watertight film" (Penn State). Wet caps carry more bacteria into storage. A maitake grower's guide says to "stop misting with water a day before harvest" (Maitake at a Glance).

In our chamber, humidity in the 6 hours before harvest ranged from 70 to 94 %. Only one harvest, a shiitake, had the humidifier switched off beforehand, 4.7 hours before picking. A few hours of drier air before you pick is an easy habit to try.

How do you know mushrooms have gone bad?

Usually your nose tells you first. In a study of retail enoki packs, "off-odor emerged earlier than the other defects" (Ma et al. 2026). The other signs, from a study of oyster, king oyster and shiitake after fridge storage: brown or yellow spots, sticky gills, a soft or rubbery texture, and a musty or putrid smell (Schill et al. 2021). Yellow-to-brown blotches are usually Pseudomonas bacteria (Penn State).

Throw them out if they're slimy, smell sour or fishy, or are bruised or spoiled (Health Canada). These checks won't catch botulism, though: in the study above, the toxin formed while the mushrooms "still appear edible". If they sat sealed and warm, throw them out even if they look and smell fine.

How can you keep mushrooms longer?

Freeze them cooked, dry them, or freeze-dry them.

• Freezing: "Most mushrooms will freeze better if they are heat treated either by steam blanching or sautéing", and sautéing is "the preferred method for many varieties" (Oregon State). Cooked and frozen, they keep 8 to 12 months (Health Canada). Freezing keeps colour, aroma and texture better than drying (Dawadi et al. 2022). You can freeze them raw, and it's safe, but they thaw soft and watery: the USDA's handbook describes frozen mushroom caps as "water-soaked and extremely soft" (USDA Agriculture Handbook 66, p. 415), and cooking first "slows or stops the action of enzymes which cause loss of flavor, color and texture" (National Center for Home Food Preservation). Raw-frozen is fine for soups and sauces.
• Drying: "Most mushrooms dry well", including shiitake and oyster, until they are "crisp or brittle" (Oregon State). University guides set the dehydrator between 120 °F (about 49 °C, Oregon State) and 140 °F (60 °C), which takes 8 to 10 hours (Colorado State). Don't turn it up to finish faster. Too hot, and the outside cooks before the inside dries, so "the moisture cannot escape". Clemson calls this case hardening (Clemson Extension). Lower is also kinder to flavour and nutrients. In a study of oyster mushrooms, ones dried at 40 °C (104 °F) kept their colour, shape and antioxidants best; at 60 and 80 °C (140 and 176 °F) they came out darker and their structure collapsed (Villalobos-Pezos et al. 2024). If you're drying for potency, as with lion's mane or reishi, stay at the low end.
• Freeze-drying: another option if you have a home freeze dryer. In a study of shiitake, freeze-dried mushrooms soaked water back up faster than hot-air or infrared-dried ones and came out "similar in appearance to the fresh sample", thanks to their porous structure (Zhao et al. 2019). Studies disagree on nutrients, though: in the oyster study above, freeze-dried mushrooms kept the least ergothioneine, an antioxidant, of any method (Villalobos-Pezos et al. 2024). We found no university guide that covers freeze-drying mushrooms at home or says how long they keep, so store them like dried ones (below).
• Pickling and canning: button mushrooms only. Oregon State says "only domestically grown button mushrooms may be safely canned", and the tested pickling recipe is for buttons too (Oregon State; National Center for Home Food Preservation). There's no tested recipe for oysters or other specialty mushrooms.

How do you store dried mushrooms?

Airtight, in small batches, somewhere cool and dark, and check on them.

• Condition them first. Put the cooled mushrooms loosely in a jar about two-thirds full, cover it loosely and shake it daily for 4 to 10 days. If beads of moisture show up inside, they go back in the dehydrator (Colorado State). This catches pieces that weren't quite dry.
• Use glass jars with tight lids. Glass lets you see moisture collecting. Freezer containers, freezer bags and vacuum packing work too (National Center for Home Food Preservation).
• Pack small batches. Every time you open a jar, the mushrooms get "air and moisture" (NCHFP), so pack what you'll use at once.
• Keep them cool and dark. Heat shortens storage life: NCHFP gives dried fruit a year at 60 °F (16 °C) but six months at 80 °F (27 °C) (NCHFP). Stored that way, dried mushrooms keep 6 to 12 months (Colorado State), or up to a year in an airtight container (Missouri).
• Check them. Mushrooms that seemed bone dry can pick moisture back up. If they've gone soft, use them now or dry them again; if they're mouldy, throw them out (NCHFP).
• A desiccant pack is optional. None of the university guides mention one, but a food-safe silica gel pack soaks up the moisture that gets in each time you open the jar. Oxygen absorbers "are only recommended for storing (properly) dried foods", a food-safety specialist writes on Ask Extension, so make sure they're fully dry before adding one.
• Rehydrate in the fridge. Drying stops bacteria growing but doesn't kill them. Listeria, Salmonella and others "can survive on low-moisture foods", Missouri warns, so soak dried mushrooms in the fridge "to reduce the risk of pathogens growing rapidly" (Missouri).

How do you store yours? If you've found a way to keep fresh mushrooms longer, or a drying setup that works well, I'd like to hear about it: team@demetermycolabs.com. I read all of it.

The pinks I picked while writing this got eaten the same day.

— Sharon

This post is general information from published research and our own grows, not food-safety or medical advice. When in doubt, throw it out. If you feel sick after eating mushrooms, call Poison Control (1-800-222-1222 in the US) or a doctor.