Chestnut Mushroom Liquid Culture

Description

This is a 10 ml syringe of living chestnut mushroom mycelium in a sterile nutrient broth. Each batch is grown from a single isolated culture, so the genetics stay the same from syringe to syringe. You inject it straight into sterilized grain, and it usually shows growth within about a week.

Chestnut mushrooms grow in dense bouquets. Young caps are small, round and copper to chestnut brown, with a slightly sticky shine and small scales, on slim cream stems. The gills start pale yellow and turn rusty brown as the caps mature. This is a different mushroom from the brown cremini some grocers sell as “chestnut” mushrooms.

Flavor and kitchen uses

Chestnut mushrooms taste nutty and a little peppery, milder than shiitake. The caps turn silky when cooked, and the stems stay crunchy, a bit like celery or asparagus. They hold their shape through long cooking.

• Saute in butter with garlic and thyme.
• Stir into risotto near the end of cooking.
• Add to miso soup or a clear broth.
• Toss into stir-fries, stems and all.

Cook them well, and eat a small portion the first time, as with any mushroom new to you.

Growing profile

Parameter	Chestnut
Colonization temperature	Room temperature, about 70 to 75°F (21 to 24°C), in the dark
Fruiting temperature	55 to 70°F (13 to 21°C)
Humidity	85 to 90%
Light	Indirect light, bright enough to read a book
Fresh air	Moderate. A vented humidity tent or fruiting chamber works.
Days to colonize	14 to 21 days on grain, then 4 to 6 weeks on a sawdust block
Days to first harvest	17 to 38 days after fruiting conditions start. Pins can take 12 to 28 days and are ready 5 to 10 days later.
Syringe to first harvest	About 2 to 3.5 months (our estimate)
Substrates	Hardwood sawdust with bran. Outdoors, hardwood logs such as maple, oak, alder, beech or birch.
Typical yield	2 to 3 flushes per block, each smaller than the first

Difficulty: Intermediate. Chestnut grows cleanly but slowly. It is slow to pin, and it wants a cooler fruiting space than oysters do. GroCycle calls it relatively easy but harder than oyster.

Tips for success

• Shake the syringe hard for 30 seconds to break up the mycelium. Wipe the injection port and needle with alcohol, then inject 1 to 2 ml per quart jar of sterilized grain, or 3 to 5 ml per all-in-one grow bag. One syringe covers about 5 to 10 jars.
• Let the block finish colonizing fully before you move it to fruiting conditions.
• Be patient after you start fruiting. Pins can take three to four weeks to show.
• Keep the humidity steady and give the block light. Pins form toward the light.
• Harvest the whole cluster while most caps are still rounded, before they flatten and drop spores.
• On logs, stack them raft-style on the ground in shade and expect the first flush in about a year.

Healthy culture or contamination. A healthy culture has clear to slightly hazy broth with white, cloud-like wisps or clumps of mycelium that settle when the syringe sits and spread out when you shake it. It smells mild or earthy. Warning signs are broth that turns evenly milky or murky and stays that way, a sour or rotten smell, a film or slime on the surface, or green, black or pink growth. If you are unsure, put a drop on an agar plate before you inoculate grain.

Kit includes

• One 10 ml luer-lock liquid culture syringe of living Pholiota adiposa mycelium in sterile nutrient broth.
• One sterile needle.
• One alcohol prep pad.

To use it you also need sterilized grain jars or an all-in-one grow bag with an injection port.

Storage

Refrigerate the syringe at 2 to 8°C (36 to 46°F) as soon as it arrives, and keep it in the dark. Do not freeze it. Use it within 3 months for the fastest, strongest growth. The mycelium stays alive longer in the fridge, but it slows with age. Before use, let the syringe warm to room temperature for a few hours and shake it well.