Buying guide

How to tell fresh mushrooms from old

Firmness, smell, color and moisture. Plus the paper-bag rule from university extension services.

Updated October 13, 2026

Fresh mushrooms look dry on the surface, feel firm and springy, and smell clean and earthy. As they age, they lose water, then start to break down. Here's how to read the signs, species by species, and how to make them last at home.

Signs of a fresh mushroom

Firm and springy. Caps and stems bounce back when you press them gently.
Dry, clean surface. Slightly cool and matte. No wet patches or shine.
Even color for the variety, with crisp gill edges.
A clean, earthy smell. Some varieties smell faintly sweet.

Signs it's past its best

Slime or wet, dark spots. The clearest sign of spoilage.
A sour, fishy or ammonia smell. Throw it out.
Limp, wrinkled or curled edges. It's drying out. Still usable if it smells fine, but cook it today.
Visible mold (fuzzy growth of a different color). Discard.

Penn State Extension advises discarding produce that's bruised, damaged or contaminated. When in doubt, throw it out.

What to look for by mushroom

Lion's mane Bright white to cream. Yellowing and a sour smell mean it's aging. Oysters Springy caps with crisp gill edges. Goldens and pinks fade fast; buy them the day you cook. King oyster Firm, bright white stems. Spongy or yellow patches mean age. Shiitake Firm, dry caps and clean gills. Dark wet spots or slimy gills mean it's old. Maitake Firm, dry fronds. Dark wet edges or a sour smell, no. Chestnut Caps can be slightly tacky, which is normal. Mushy stems are not. Enoki White and dry. Yellowing, slime or a wet base: discard. Always cook enoki. Morel Firm and dry. Soft, slimy or moldy morels should be thrown away. Always cook morels.

How to store fresh mushrooms

University extension services agree on the basics.

Refrigerate them. Penn State Extension says to always store mushrooms in the refrigerator, either in the original container or in a paper bag.
Use paper, not plastic. Loose mushrooms dry out, and plastic bags trap moisture that speeds spoilage. Utah State University Extension recommends a porous paper bag for loose mushrooms for the same reason.
Don't wash until you cook. Utah State advises cleaning mushrooms only when you're ready to use them.
Keep them away from raw meat, poultry, seafood and eggs in the fridge, as Penn State recommends.
Plan on a few days. Penn State's guidance is up to three days; Utah State says properly stored mushrooms last about five. Delicate oysters are at the short end and king oysters at the long end.

Cornell's Small Farms Program, writing for growers, makes the same point about paper bags and adds that they don't keep mushrooms fresh for long unless they're sold within a day or so of harvest.

Keeping them longer

Penn State Extension gives tested methods for both freezing and drying. For freezing, they recommend steam-blanching sliced mushrooms for about five minutes before cooling and packing them. For drying, they recommend a food dehydrator for eight to ten hours. Their guide also covers pressure canning. Their advice on wild mushrooms is blunt: don't can them, and unless you're an expert, don't forage.