Q. Dear Mike: On three recent occasions, I've found stemless, mushroom-like 'bulbs' underneath my lawn. I was aggressively pulling weeds, removed some soil, and saw them about an inch and a half below ground. I did a search on the Internet and arrived at the uneducated guess of black truffles. I know that some truffles grow around the roots of oak trees, which is what I have on my lawn. How do I go about making sure these really are truffles and not some kind of poisonous fungi? Thanks,
- --Juan in Woodbridge, VA
Anyway, you might well have found a 'truffle tree' says Paul, who explains that the first big clue is scent. When these underground puffballs mature, they become very fragrant; so fragrant a walnut-sized specimen of the famous European white truffle can infuse an entire house with its enticing aroma! This scent lures woodland creatures like squirrels and voles to dig down and eat them. When those creatures later, eh, 'release' the results of that meal, they sow the 'seed' (the mushroom's spores), hopefully near a tree the new growth can colonize.
That they are always found among the roots of trees, explains Paul, is evidence of the amazing symbiotic relationship they have developed with those tall stately plants. The truffles convey the plant-enhancing benefits of mycorrhizal mycelium, enabling the tree's roots to better utilize food and water, making the plant healthier and happier. They also inhibit the growth of many other plants in the vicinity (much like black walnuts do without fungal help), reducing competition for the tree's resources. It's a great deal for a tree to have truffles.
Paul feels that the best 'truffle trees' in the United States are conifers: Pines, spruces, Douglas firs and hemlocks. In Europe, they're often also found under willows, but not in America so far. That doesn't mean they're not there, however. Paul explains that their hidden life leads many researchers to believe that there's a lot we don't know about truffles. They love mixed pine and deciduous forests, and although they do occur under oaks, the specific type of North American truffle that favors oaks tends to not be as flavorful as some others. In Europe, oak truffles are another story—but forget it! We barely got time for this one!
Paul adds that truffles prefer to colonize the roots of 'younger' trees—in the 10 to 40 year old range. (Professional truffle growers in Europe plant young filberts and oaks in areas with existing colonies in the hope the new trees will be colonized.)
Truffles typically begin ripening and emitting their distinctive and voluptuous smell in the Fall, with the scent strongest in winter and early Spring. That smell is the biggest clue as to whether you have true truffles or 'poggies' (Rhizopogon species), another type of stemless underground mushroom that, while thought to be safely edible, is not nearly as flavorful as a truffle.
"You can tell by the smell," stresses Paul, who adds that poggies also have the remarkable quality of bouncing a foot into the air, like a rubber ball, if you toss them at the floor. "True truffles thud," he explains. Poggies are also more symmetrical inside; cut them down the center and it looks like a fine sponge, explains Paul, while true truffles "tend to have fantastic ridges and furrows divided by white tissue."
But even though Paul explains that "there are no known poisonous truffles or poggies," he urges the caution exhibited by virtually every mushroom expert who's still around to offer advice ("there are old mushroom hunters and there are bold mushroom hunters, but there are no old, bold mushroom hunters…"); and that's not to eat anything without a positive ID. "There are some unsafe mushrooms that, when young, look and behave a bit like truffles. And there are many truffles and poggies yet to be discovered," he warns.
He strongly recommends the book "Field Guide to North American Truffles," available through his website and from the publisher, The North American Truffling Society, who also provide a free truffle ID service. You'll find all the details, and lots of fun truffle info, at their website.
Just please don't go tearing up the forests in search of this expensive and desirable food; a lot of damage is done by people randomly searching for the elusive things, says Paul. But if you see vole holes around a tree, detect a delicious and somewhat erotic odor (the best truffles have true aphrodisiac properties), then yes, you can gently dig around those roots. If truffles you find, return every winter, says Paul. Like morels, they're found in the same spot year after year.
After making sure they ARE truffles, don't cook them. Unlike most mushrooms, Paul explains that truffles are best enjoyed uncooked. They're typically served in small amounts, with fatty animal products like rich cheeses, eggs and butter. Then be conscious of your smell afterwards, says Paul. You'll give off a scent after eating truffles that….that…well, let's just say that certain other people may notice, and not in a bad way…