Shiitake’s Broad Reach
Interest is growing in a mushroom famed for its culinary and medicinal qualities.
Prized by chefs and gourmands the world over, shiitake mushrooms are renowned for their smoky, full-bodied flavor and pleasing appearance, with their sturdy white stems and fleshy brown caps. Consumed in fresh and dried form, shiitake are not only used in many Asian dishes, including Japanese miso soup, but have long been revered for their medicinal properties in China.
Exactly how these cherished fungi are cultivated, however, is far from common knowledge. Both in nature and in traditional cultivation, shiitake grow on logs. Also known as black forest mushrooms, shiitake are the result of a very specific organic process that involves moist, shady conditions and certain kinds of hardwood trees. In the US, shiitake are generally grown on red or white oak.
Aaren Hatalsky, caretaker of Wing Road Farm in Greenfield, New York
(www.wingroadfarm.com), cultivates shiitake on her 15-acre lot outside Saratoga Springs. Hatalsky prefers logs that are about four or five inches in diameter. “That size is where you get the greatest amount of surface area per log,” she says. “It’s going to last quite a long time, and there’s going to be enough heartwood [the darker core of the log] and enough nutrients for the mushrooms to last four years on it, but it’s going to be a little lighter and easier to lift.” She points out that the logs have to be taken from living oak cut in the winter before the sap has risen.
The logs are inoculated with mycelium, little cotton-like masses from which the mushroom fruits. The strain used depends on the climate—a region such as upstate New York requires a cold-hardy variety. Other essential materials include a drill with a depth-stop to create the holes in which the shiitake will grow, a plunger to get the mycelium into the holes and a sealant—ideally beeswax, a medium that works well for organic certification.
Once inoculated the logs are stacked on a pallet off the ground under the shade of trees, where the wood can be easily watered or will receive some rain through the branches. And then colonization begins, with the fungi slowly decomposing the oak and drawing nutrients from the log. Shiitake growing is not a pursuit for the impatient. “I was taught that you inoculate in April and wait until the following May,” Hatalsky says. “It’s almost 13 months before you’d actually expect your first crop.”
When the shiitake do finally appear, it’s an impressive sight, as stems protrude from the wood to unveil their charming rounded forms. “Each log can be fruited about two to three times per season, depending on how much time there is in between,” says Hatalsky. The logs optimally yield around six pounds of shiitake apiece over four years, after which they can be used as firewood.
For those considering growing shiitake as a commercial venture, Hatalsky has a word of caution. “You’d have to do it pretty intensively,” she says. “I think a lot of people like the idea that they can just do 20 or so logs and have enough for a small farm or a family. It’s really not a lot when you break it down. With my 50 logs, if I was very lucky, I’d get something like 100 pounds per season.”
A faster, more bountiful alternative process is cultivating shiitake on sawdust. This labor-intensive method requires specialized indoor facilities and is designed for a year-round commercial operation. (In fact, a surprising 95% of the shiitake produced in the US is grown on sawdust, even though log-based farms are more numerous.) Northwest Mycological Consultants, Inc. in Corvallis, Oregon (www.nwmycol.com) offers its services to both large-scale sawdust-based shiitake farms and smaller log-based growers—Hatalsky herself cites NMC as an excellent source for both mycelium and advice.
The co-author of Shiitake Growers Handbook with Paul Przybylowicz (Kendall/Hunt), NMC president John Donoghue is heartened by the growing interest in the mushrooms. “I’m a firm believer that mushrooms are good for you,” he says. “There’s good science behind some of the compounds that they’ve isolated from shiitake.” These extracts include lentinan, a beta-glucan being researched for its anti-tumor qualities; eritadenine, which has been shown to lower cholesterol; and ergothioneine, an amino acid with antioxidant properties. Shiitake also contain ergosterol, a substance that, as Donoghue explains, “is a lot like vitamin D; in fact, it turns into vitamin D in sunlight.” This aspect of the mushroom gives it another crucial benefit—it is one of the only significant vegan sources of vitamin D, a key part of any diet that is most readily found in fatty fish and fortified dairy products.
Donoghue proudly notes that there is a certain fascination with how shiitake look and how they are grown. “If more home gardeners and farmers cultivated shiitake,” he observes, “they’d be growing something that is good for them and learning all about another side of life.”