Gourmet mushrooms are all the rage right now, and foodies and gardeners alike are getting in on home cultivation of these fascinating fungal creatures. With the right substrate mixture and growing conditions, anyone can grow their own delicious, organic mushrooms at home. In this article, we’ll explore how to make a popular substrate called “masters mix,” and which species grow best on it.
What is Masters Mix?
Masters Mix is a substrate mixture that is commonly used by mushroom growers for a variety of culinary mushroom species, including beginner-friendly favorites like Oyster Mushrooms and Lion’s Mane. Masters Mix is comprised of 50% hardwood fuel pellets and 50% soybean hulls. Hardwood fuel pellets are readily available at grocery stores, Walmarts, and Targets (check at the grilling supplies), and are compressed sawdust from hardwood trees. Their intended end use is for smoking foods, but they provide an excellent foundation for wood-loving gourmet mushrooms. Soybean hulls are the outer coating of soybeans and can be harder to source. Fortunately, Amazon carries pelletized soybean hulls that are visually similar to hardwood fuel pellets, and mix up nicely with them.
Why Do We Love Masters Mix?
Bear in mind that a lot of gourmet mushrooms will grow on a range of substrates. Oysters, in particular, are as happy to colonize wet cardboard or old t-shirts as they are wood chips. I’ve coaxed Lion’s Mane to produce some cute little fruiting bodies on animal bedding. That’s all well and good, but if you’ve perused any mushroom cultivation websites or Facebook groups, you have no doubt seen some truly monster flushes, with fruiting bodies often weighing several pounds at harvest.
Growers typically cultivate those big mushrooms on Masters Mix. This supplies necessary lignin (from the fuel pellets), as well as mushroom-appropriate carbohydrates and nitrogen (from the soybean hulls).
Let’s Mix It Up!
Putting Masters Mix together is simple enough. If you want to go by weight, a five-pound batch works out as one pound each of hardwood fuel pellets and soybean hulls, with three pounds of water. I used to mix it up in a bucket, but now I do it all right inside a spawn bag. The bag then goes directly into a pressure cooker for sterilization.
It’s been easier, in that process, to work volumetrically. That works out to two and a half cups each of hardwood fuel pellets and pelletized soybean hulls. Then, pour in 1.4 liters (three-ish pounds) of water. Americans, don’t panic about the liter thing. A quart-sized Mason jar is approximately a liter, if you want to estimate. The OXO Salad Dressing Shaker I own is graduated to 350mL. I pour four of them into the bag and bango-presto! I’m ready to sterilize my substrate.