Fermented Mushrooms

Directions

• Before We Start

  Use fresh mushrooms. If they’re slimy, leaking, or heavily spotted, skip them. Fermentation doesn’t fix bad produce, but it does preserve good produce!
  Salt ratio (2% by weight): Here is the simple equation to knowing how much salt to use salt (g) = mushroom weight (g) × 0.02. If the mushrooms aren’t exactly 600 g after trimming, recalculate the salt.
  Salt type matters. Use non-iodized salt (kosher or fine sea salt). We use morton kosher salt.
  Fermentation Methods: There are several options, you can leave it in a warm spot in your house, set it on a seedling mat, or use a DIY fermentation chamber.

• Clean and Trim

  Rinse mushrooms quickly under cool water, then pat dry. Trim the dry/dirty stem ends.

• Salt

  Add mushrooms to a large bowl. Sprinkle in the salt and toss well until everything is evenly coated.

• Bag and Remove Air

  Transfer to a vacuum bag and seal.
  
  No vacuum sealer? Use a gallon zip-top bag. Add the salted mushrooms to the bag and lower the unsealed bag into a sink of water (keep the zipper above the water line) to push air out, then seal while it is under the water. The pressure from the water forces the air out of the bag, creating the air free envronment.

• Freeze Overnight

  Freeze the sealed bag 8–12 hours. This step helps the mushrooms release their juices.

• Ferment

  Place the sealed bag in your fermentation chamber (Set to 82F) or leave in a warm place in your home for 2–5 days. The bag will puff up some with CO₂ — this is normal and a sign of active fermentation.
  
  What to expect:
  Day 2: very mild tang, still fairly firm
  Day 3: mild tang, big mushroom umami, still fairly firm (usually the sweet spot)
  Day 4: noticeably tangier, deeper savoriness
  Day 5: very tangy, deeper savoriness (typically too strong for most people)
  
  If this is the first batch, start tasting on day 2 and stop when it tastes perfect to you.

• Refrigerate

  Once the flavor is where we want it, transfer mushrooms + brine to a clean airtight container and refrigerate. Cold storage slows fermentation dramatically.
  
  This will keep in the refrigerator for 3–4 weeks.
  
  Use them by chopping and folding into aioli or a Greek yogurt sauce. Slice over steak, burgers, or lettuce wraps. Toss into grain bowls or salads (they bring acid like a vinaigrette). Stir into pan sauces at the end (treat it like finishing acid). Blend a spoonful of brine into dressings for instant complexity.