Pickling Mushrooms: A Tested Half-Pint Canning Method

Shelf-stable pickled mushrooms need the tested whole-button recipe, with its separate lemon simmer, its oil-vinegar marinade and processing times set by altitude. Your chilled mushroom dish keeps for a shorter time in the fridge, and a tight lid on its own does not show that a jar is safe.

Pickled mushrooms end up as two quite different foods. The first is a chilled dish that lives in the fridge, and the second is a canned jar that can sit in the pantry. Only a tested recipe, followed through every step of its heat process, makes the pantry kind. The sour taste and the tight lid on your jar cannot tell you which kind you made.

Fridge Pickles or Pantry Jars?

Penn State Extension gives cooked leftovers a general limit of no more than four days at 40°F or below. Your cooked mushroom dish dressed with vinegar still needs a short plan like that in the fridge. That general limit does not prove that every fridge-pickle formula keeps for four days, though. The tested canned method below sets no storage time for a different fridge mixture either. Extra vinegar or a longer soak cannot stand in for the missing evidence that a mix keeps for weeks.

Shelf-stable mushrooms need a much more exact process. Mushrooms are low-acid foods, and the spores of Clostridium botulinum are difficult to destroy at boiling-water temperatures. Tested pickling recipes add enough acid and fix the preparation and the heat process. With that acid in place, the National Center for Home Food Preservation, or NCHFP, can give a boiling-water method for marinated whole mushrooms, while plain canned mushrooms require a pressure-canning method of their own.

Five percent acidity on the vinegar bottle describes the vinegar, and it tells you nothing on its own about the finished jar. The amount of mushrooms, the other ingredients and the preparation all change what ends up in that jar. So pouring undiluted vinegar over any amount of mushrooms does not give you a safe preserving recipe.

Which mushrooms can you pickle and can?

The NCHFP recipe makes about nine half-pint jars from small cultivated button mushrooms. Oregon State University Extension limits mushroom canning to domestically grown button mushrooms, because other kinds differ in density and texture. The caps you use should be very fresh, unopened and less than 1¼ inches across. You wash them and trim each stem to leave ¼ inch attached, and large sliced caps cannot take the place of the whole mushrooms the recipe names.

Other edible mushrooms have other ways to keep, such as freezing mushrooms or drying them. Each of those methods gives you a different kind of ingredient, and neither makes the same acidified jar.

The table lists the amounts for the full published batch and what goes into each jar. Your bottled lemon juice goes into the first cooking liquid, and you drain that liquid off before the mushrooms meet the final marinade. Since the yield is approximate, each jar still follows the packing directions and the required headspace.

NCHFP's pickling guidance tells you to keep tested ingredient proportions and leave the vinegar, food and water ratios alone. This mushroom method names bottled lemon juice and white vinegar of known acidity. If you switch to another acid, add extra mushrooms or use a different jar size, the processing time no longer covers your jar.

The Lemon Simmer and the Oil-Vinegar Marinade

The drained mushrooms move from a lemon-water simmer to a separately heated oil-vinegar marinade, and the recipe keeps those two stages apart. Before filling begins, set out a boiling-water canner with a rack, clean half-pint canning jars, suitable canning lids and a jar lifter. Keep the jars hot and prepare the lids the way their maker directs, so the hot food can move straight into the canner.

1. Prepare the small caps

   Wash the mushrooms and trim each stem to leave ¼ inch attached to the cap. Use the small, unopened cultivated button mushrooms specified above.

2. Simmer in lemon water, then drain

   Put the mushrooms in a saucepan with the ½ cup of bottled lemon juice and enough water to cover them. Bring to a boil, simmer for 5 minutes, then drain the mushrooms.

3. Make the separate marinade

   Combine the measured oil, white vinegar, oregano, dried basil and canning salt in a saucepan. Stir in the chopped onion and diced pimento, then heat the mixture to boiling.

4. Fill the hot half-pint jars

   Put ¼ garlic clove and 2 or 3 peppercorns in each jar. Add mushrooms and the hot, well-mixed oil-vinegar marinade, leaving ½ inch of headspace.

5. Finish the packing

   Remove trapped air bubbles and adjust the headspace if needed. Wipe the jar rims, apply the lids according to their directions, then process the jars using the altitude table below.

The ½ inch of headspace is the empty space below the rim once you have filled the jar and removed the bubbles. The water over the closed jars during canning is a separate depth, and you measure it in the canner itself.

Penn State explains that oil can interfere with heat penetration and sealing. Marinated whole mushrooms are a tested exception, because the recipe puts the measured oil in alongside the acid and the set preparation. That exception does not reach mushrooms covered with oil alone, or extra oil you add to a different recipe.

How long do you process the half-pint jars?

The published schedule applies to hot-packed half-pint jars. Pint jars fall outside it, even when they hold the same mushrooms and marinade.

The canner rack holds the jars up inside the pot. NCHFP's boiling-water canner directions preheat the water to 180°F for hot-packed food, then load the filled, closed jars upright with a jar lifter. Water must cover the jar tops by at least one inch. For the 35-minute process, which runs past 30 minutes, NCHFP calls for two inches of water above the jars.

Cover the canner and bring the water to a vigorous boil before you start the timer. Keep a complete boil for the entire required time, and add boiling water around the jars if you need to keep them covered. If the water stops boiling, bring it back to a vigorous boil and restart the full processing time. Minutes in water that is merely hot do not count as uninterrupted boiling-water processing.

After the full time, turn off the heat and take off the canner lid. Wait five minutes before you lift the jars out upright, then set them on a towel or cooling rack with at least an inch between jars. The five-minute wait lets the canner contents settle, and it replaces none of the time in the altitude table.

Failed Seals, Lost Seals and Shelf Storage

Let the jars cool undisturbed for 12 to 24 hours. NCHFP's seal-testing directions warn that tightening hot bands again or pressing the lids too early can interfere with the seal as it forms. So the seal check waits until the jars have cooled.

For two-piece metal lids, take off the ring bands and look at the flat lids once the jars are cool. If the center springs back when you press it, the jar has not sealed. On a sealed jar, the center sits slightly concave and does not flex. That seal shows the lid holds a vacuum, but it cannot prove that the recipe, jar size or processing time was correct.

NCHFP's cooling guidance says to use refrigerated failed-seal contents within several days. Its storage page allows up to a week when you find the failure within 24 hours, and the table keeps the shorter, more cautious limit. Reprocessing has its own conditions too, including a new lid and a fix for any faulty jar. It works only for a failure you catch quickly, and it cannot rescue a jar that has sat unsealed on a shelf.

Properly processed, sealed jars keep best in a clean, cool, dark and dry place, ideally 50 to 70°F. NCHFP recommends canning only what you will use within a year for best quality, and one year is no guarantee under every storage condition. Store the jars without their ring bands and mark the contents and date on every jar. Without the band, you can spot a lost seal more easily and no moisture gets trapped around the lid.

Oregon State's guide to pickling vegetables warns against eating any jar that unseals in storage. Once you open a sealed jar to serve it, the rest of the jar goes in the fridge. Adding herbs or dressing to a portion at the table leaves the rest of the jar exactly as you preserved it, and it does not make that jar keep any longer.