How To Store Mushrooms So They Won't Get Slimy

Say goodbye to slime.

Portobello Mushroom
Photo: Yulia-Images/Getty Images

Mushrooms are a hearty and earthy addition to pastas. They are a great replacement for meat in many meatless main recipes. Mushrooms are also a welcome addition to stuffings and gravy on Thanksgiving. There are many varieties of this versatile ingredient, from morels to shiitakes, to the humble white button mushroom found in every grocery store produce section. No matter the variety you buy, if not stored properly, they all end up the same: slimy. And that sticky film that forms on the outside of the mushrooms is a harbinger of inedible mold to come. Although no mushroom can last forever, you can make the mushrooms you purchase last much longer by storing them properly. Just like keeping asparagus in water, there is a right way to store your mushrooms and we’ll break down what works best. 

Here’s What Doesn’t Work 

Keeping your mushrooms in the shrink-wrapped plastic container they came in from the grocery store.

It seems counterintuitive to remove mushrooms from their packaging, but in the long run you’ll be thankful you did. Mushrooms contain a lot of water and in that plastic box, under plastic wrap, they will sweat. Both the plastic box and wrap trap excess moisture and, promote the dreaded slime forming on the mushrooms. If you purchase mushrooms by weight in the grocery store you’ll notice the store offers paper bags to place them in, that’s because paper bags are breathable unlike plastic.

Once home, make sure to store your mushrooms whole; purchasing pre-sliced mushrooms or cutting them in advance will only save you prep time if you're planning to use them very soon, otherwise sliced mushrooms will go bad much faster than whole. 

The vegetable bin is also not a great place to store mushrooms. Similar to how the plastic boxes trap moisture, humidity gets trapped inside the enclosed vegetable bin.

What Exactly Is The Slime?

There is no appetizing way to phrase this, but it's the byproduct of bacteria feasting on the mushrooms, which in turn cause the fungi to eventually decompose. These bacteria aren't typically harmful to humans, but once they start breaking down the mushrooms, it won't be long before harmful mold and bacteria arrive on the scene.

How To Store Mushrooms Properly

Place whole mushrooms in a paper bag and store the bag on a shelf in the refrigerator. If you didn't grab a paper bag at the store, you can place the mushrooms loosely wrapped in a paper towel inside a Ziplock plastic bag, just don’t seal the bag so that air can circulate. You'll similarly want to put the plastic bag in the main compartment of your fridge. 

Should I Wash Mushrooms Before Storing?

It's important to remove dirt and debris from mushrooms, especially when working with wild varieties, but you don't clean mushrooms the same way you do other produce. Mushrooms are porous and absorb water like a sponge. As we discussed above, excess moisture is the enemy, not just when storing but also when cooking, as water will prevent browning.

The best way to clean mushrooms is to use a paper towel to swipe off any dirt. It's a little tedious, but thankfully most mushrooms purchased at the grocery store, especially the pre-packaged kind, are already fairly clean since they are often cultivated indoors. Working with wild mushrooms, however, is very different and requires more thorough cleaning.

If I'm Too Late And They Are Already Slimy, Can I Still Use Them?

Slimy mushrooms aren't inherently inedible, but they aren't in great shape either. If the slime is minimal, i.e. you caught it early, you might have another day or so to cook with them before they start to turn black, get mushy, or visible mold appears. It’s best to trust your senses: do they smell off or seem discolored (even if just in patches)? If so, toss them out. Nobody likes to waste fresh produce or money, but it’s better safe than sorry.

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