Preserving Mushrooms (SP 50-919)

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Mushrooms are not a true vegetable, but a fungus — a plant that does not have any roots or leaves and does not bear flowers or seeds. Most varieties of mushrooms grow in the wild. There are over 38,000 varieties, some edible and some highly toxic. Unless you are an expert in mushroom identification, it is advisable to only preserve commercially sold mushrooms.

Mushrooms can be preserved by canning, freezing, drying and pickling. Caution: Because of density and texture differences, only domestically grown button mushrooms may be safely canned. Other varieties can be frozen or dried.

Canning (whole or sliced)

Mushrooms should only be canned in half-pint and pint jars. It takes an average of 2 pounds of mushrooms per pint and 1 pound per half pint.

Select brightly colored small to medium domestic button mushrooms. They should have short stems, tight veils (unopened caps), and no discoloration.

To can:

  1. Trim stems and discolored parts. Soak in cold water for 10 minutes to remove dirt. Wash in clean water. Small mushrooms can be left whole. Halve or quarter larger ones.
  2. Put mushrooms in a saucepan and cover with water. Bring to a boil and simmer for 5 minutes.
  3. Pack hot into hot jars, leaving 1-inch head space. Add ½ teaspoon salt per pint if desired or ¼ teaspoon per half-pint. For better color, add ⅛ teaspoon of crystalline ascorbic acid powder or a 500-milligram tablet of vitamin C.
  4. Add fresh hot water, leaving 1-inch head space.
  5. Adjust lids and process half pints and pints in a pressure canner at 240ºF, 10 pounds pressure weighted gauge and 11 pounds dial gauge, for 45 minutes. (Ask your county Extension Service for pressure adjustments if you live above 1,000 feet.)
  6. After processing, remove canner from heat and let pressure return to zero. Remove weight or slowly open petcock. Wait 10 minutes before removing lid.

Freezing

Most varieties of mushrooms freeze well. Choose edible mushrooms free from spots or decay. Sort according to size. Wash thoroughly in cold water. Trim off ends of stems. If mushrooms are larger than 1 inch across, slice them or cut into quarters.

Most mushrooms will freeze better if they are heat treated either by steam blanching or sautéing.

To steam: Mushrooms will hold their color better if pretreated before they are steamed. Soak mushrooms for 5 minutes in a solution containing 1 teaspoon lemon juice or 1½ teaspoons citric acid to 1 pint of water. Drain mushrooms. Place in a steamer basket and steam whole button mushrooms for 5 minutes, quarters for 3½ minutes, or slices for 3 minutes. Cool in ice water. Drain and package cold mushrooms in freezer containers. Seal, label and freeze.

To sauté: This is the preferred method for many varieties of mushrooms. Wash and slice or cut mushrooms into serving-size pieces. Heat a small quantity of butter, margarine or oil in a heavy skillet. Add mushrooms and sauté until almost done. Remove from skillet and cool in air or set pan of mushrooms in cold water. When cold, pack into freezer containers. Seal, label and freeze.

Drying mushrooms

Dry only cultivated or wild mushrooms that are safe to eat. Most mushrooms dry well. Good varieties for drying are button mushrooms, chanterelles and morels.

Select fresh mushrooms with closed caps and visible gills under the cap. Clean them with a soft brush or cloth and quickly rinse to remove any dirt. Cut away any questionable parts and trim woody portions from the stem. Dry whole or sliced in half. Thickness should be approximately ½ inch.

Dry mushrooms in a dehydrator at 120ºF until crisp or brittle.

To use: Rehydrate dried mushrooms by soaking them in boiling water for a few minutes until softened. Lift out of the water with a slotted spoon and add to your favorite dish.

Pickling

Because mushrooms are low acid it is important to use only tested recipes. Only use commercially grown button mushrooms.

Marinated Whole Mushrooms (Yield: Approximately 8 half-pint jars)

  • 7 pounds small whole button mushrooms
  • ½ cup bottled lemon juice
  • 2 cups olive or salad oil
  • 2½ cups white distilled vinegar (5% acidity)
  • 1 tbsp. dried oregano leaves
  • 1 tbsp. dried basil leaves
  • 1 tbsp. salt
  • ½ cup finely chopped onions
  • ¼ cup diced pimiento
  • 2 cloves garlic, cut into quarters
  • 25 black peppercorns

Procedure:

  1. Select fresh unopened button mushrooms with caps less than 1¼ inches in diameter. Wash.
  2. Cut stems, leaving ¼ inch attached to cap.
  3. Add lemon juice and water to cover. Bring to a boil. Simmer 5 minutes. Drain mushrooms.
  4. Mix oil, vinegar, oregano, basil and salt in a saucepan. Stir in onions and pimiento. Heat to boiling.
  5. Place ¼ garlic clove and 2-3 peppercorns in each ½ pint jar.
  6. Fill jars with mushrooms and cover with hot, well-mixed oil/vinegar solution.
  7. Leave ½ inch head space. Remove air bubbles, Wipe jar rims. Adjust lids.
  8. Process half pints for 20 minutes in a boiling water canner. (For processing times for altitudes over 1,000 feet, call your local Extension Service.)
  9. After processing, remove canner from heat. Remove lid and wait 5 minutes before removing jars.

Source: OSU Master Food Preserver Program

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