How to Freeze Mushrooms the Right Way

As an Amazon Associate we earn from qualifying purchases.

Knowing how to freeze mushrooms properly comes down to one step many people skip: heat treating them before they go into the freezer. Extension guidance from Oregon State University says most mushrooms freeze better after steam blanching or sautéing. The steps below cover selecting and cleaning mushrooms, the sautéing method, cooling, packing, and labeling. They also note where the published sources stop, especially on how long frozen mushrooms keep.

Quick answer

Pick firm mushrooms with no spots or decay, wash them in cold water, sort them by size, and trim the stem ends.
Slice or quarter any cap larger than 1 inch across.
Heat treat before freezing: sauté until almost done, or steam blanch.
Cool completely, pack into freezer containers, seal, label, and freeze.

How we chose

This guide relies on university extension and the National Center for Home Food Preservation (NCHFP), which publishes research-based food preservation guidance. Three pages were opened and checked on 2026-10-27: an Oregon State University Extension catalog entry for the publication Preserving Mushrooms (SP 50-919), a Penn State Extension article titled Preparing and Preserving Mushrooms, and the NCHFP freezing guidance page. Retail sites, recipe blogs, and marketing pages were not used as factual sources for the method.

Preparing mushrooms for the freezer

Start with mushrooms in good condition. Penn State Extension advises choosing mushrooms with caps that are “either closed around the stem or moderately open with pink or light tan gills,” and with a cap surface that is “white or creamy or a uniform light brown.” Discard any with spots or decay. Choosing pieces with consistent color makes it easier to decide which ones are ready for the freezer.

Next, wash the mushrooms. Penn State’s freezing instructions say to “Thoroughly wash them in cold water and sort them by size,” and then to “Trim the ends of the stems.” Sorting by size helps pieces of similar size cook and cool at a similar pace. For freezing, Penn State also says that “If the mushroom is larger than 1 inch across, slice it or cut it into quarters.”

Drain the cleaned pieces well before cooking. The sources reviewed here do not give a specific drying method, so simple draining is the approach described in this guide.

Storing mushrooms before freezing

If mushrooms will wait before freezing, keep them cold. Penn State advises: “Always store mushrooms in the refrigerator, either in their original container or in a paper bag,” and says this works for up to 3 days. The same guide warns that “When loose mushrooms are stored out of a paper bag, they can dry out.” Freezing is best done while mushrooms are still fresh, rather than after a long wait in the refrigerator.

Sautéing before freezing

Oregon State’s sautéing method is the one most directly tied to freezing. The first step is to “Heat a small quantity of butter, margarine or oil in a heavy skillet.” Then, “Add mushrooms and sauté until almost done.” The wording is “until almost done,” so the pieces should still be slightly firm when they leave the pan.

If the pan is crowded, cook the mushrooms in batches. The Oregon State steps do not give a batch size, so use a pan large enough that the pieces are not piled on top of each other. Mushrooms cooked this way are a practical choice for soups, sauces, and other cooked dishes.

Blanching or steaming first

Oregon State states that “Most mushrooms will freeze better if they are heat treated either by steam blanching or sautéing.” Sautéing is one accepted option, and steam blanching is the other. The NCHFP freezing guidance explains the general purpose of blanching: “Blanching slows or stops the action of enzymes which cause loss of flavor, color and texture.” That passage refers to vegetables in general, so it explains why heat treatment is recommended, while the mushroom-specific steps come from the Oregon State publication.

Oregon State also describes a steaming method for mushrooms that uses a lemon juice or citric acid soak to help protect color before steaming and ice-water cooling. Exact steam times are in the publication. Check that page directly before using a steaming schedule, because this guide does not repeat them.

Cooling, packing, and labeling

Cooling comes before packing. Oregon State’s instructions say to “Remove from skillet and cool in air or set pan of mushrooms in cold water.” Then, “When cold, pack into freezer containers. Seal, label and freeze.” Follow that order. Pack the cooled pieces into containers or freezer bags, press out excess air, and label each package with the date and contents so older batches are used first.

Safety notes for wild mushrooms

Oregon State includes a warning that applies to foraged mushrooms: “Only an expert can differentiate between poisonous and edible varieties.” It also notes that “The toxins in poisonous varieties of mushrooms are not destroyed by drying or by cooking.” Cooking before freezing therefore does not make an unidentified wild mushroom safe. Freeze only mushrooms that a qualified expert has identified, or buy mushrooms from a commercial source.

For related food preservation methods, see how to preserve tomatoes and how to can green beans. For garden-side tips, see how to make garden compost quickly.

What we could not verify

What the sources do not say

The sources reviewed for this guide do not give a freezer storage time for sautéed mushrooms, so this guide does not state one. The Oregon State page does not give a storage period, and the Penn State and NCHFP pages reviewed here do not give one for frozen mushrooms either. Search results on other websites gave a range of storage periods, but those pages were not used because they were retail or general blog sources. The National Center for Home Food Preservation mushroom page could not be retrieved in this check, so its specific guidance is not summarized here.

The sources also do not describe how to thaw or use frozen mushrooms, and they do not give exact steam times. Check the original publications before following any timing, and follow tested USDA or extension guidance for any food preservation method.

Frequently asked questions

Do mushrooms need to be cooked before freezing?

Extension guidance says most mushrooms freeze better after heat treatment. Oregon State lists steam blanching or sautéing as the two methods, and the sautéing steps are described above.

How big should mushrooms be for freezing?

Penn State advises slicing or cutting into quarters any mushroom larger than 1 inch across. Sorting the pieces by size before freezing helps them cook and cool at a similar pace.

Should mushrooms be washed before freezing?

Penn State says to “Thoroughly wash them in cold water” before freezing, and then to trim the stem ends.

Can I freeze mushrooms that I foraged?

Oregon State says “Only an expert can differentiate between poisonous and edible varieties.” Freeze foraged mushrooms only after a qualified expert has identified them.

How long do frozen mushrooms last?

The sources reviewed here do not give a storage time for frozen mushrooms, so this guide does not state one. Check current USDA or National Center for Home Food Preservation guidance before setting a freezer date.

Sources

Oregon State University Extension, Preserving Mushrooms (SP 50-919): https://extension.oregonstate.edu/es/catalog/sp-50-919-preserving-mushrooms (opened 2026-10-27)
Penn State Extension, Preparing and Preserving Mushrooms: https://extension.psu.edu/preparing-and-preserving-mushrooms (opened 2026-10-27)
National Center for Home Food Preservation, Freezing: https://nchfp.uga.edu/how/freeze.html (opened 2026-10-27)