By Ellen Brown
Selecting High-Quality Mushrooms:
Choose mushrooms that are free from spots and decay. It's best to purchase commercially grown mushrooms. You can also collect your own, but unless you're a mushroom expert, do so under the supervision of an experienced expert to be 100% certain they are nontoxic.
Preparing for Freezing:
Sort according to size. Wash thoroughly in cold water and pat dry. Cut off ends of stems. Leave them whole or if mushrooms are larger than 1 inch across, you may want to slice them or cut them into quarters.
Best Freezing Method(s):
Pre-treat by blanching sliced mushrooms (1 pound at a time) for 3 minutes, or 5 minutes if whole. Cool promptly and drain. Transfer into suitable containers. Date, label and freeze.
Place clean mushrooms in a single layer on a cookie sheet in the freezer. Tray-freeze until firm. Once firm, transfer mushrooms to freezer bags or other suitable containers. Seal, label and freeze. The mushrooms will develop a rubbery texture freezing this way, but will still be suitable to use when cooking.
Before steaming, pre-treat mushrooms for 5 minutes by dipping them into an anti-darkening agent consisting of 1 teaspoon of lemon juice or 1 1/2 teaspoons of citric acid to a pint of water. After pre-treatment, steam whole mushrooms 5 minutes (buttons or quarter for 3 1/2 minutes; sliced for 3 minutes). Cool promptly and drain. Package leaving 1/2 inch of headspace. Seal, label and freeze.
Heat small amounts of mushrooms in butter in an uncovered frying pan. When almost done, set pan in a bath of cold water to cool, or remove mushrooms from pan and let them cool and room temperature. Pack in suitable containers leaving 1/2 inch of headspace. Seal, label and freeze.
Freezer containers should be moisture and vapor resistant and should not be prone to cracking or breaking at low temperatures. Containers should provide protection against absorbing flavors or odors and should be easy to label. Suitable packaging for freezing mushrooms includes freezer-grade plastic bags, rigid plastic containers or glass containers and heavy-duty aluminum foil.
Maximum Storage Time:
10 to 12 months at 0ºF.
Add frozen mushrooms directly into dishes while cooking.
Place mushrooms in an open paper bags and store in the refrigerator for 4 to 5 days.