In Minnesota, and much of the midwest, there is a genus of very small but delicious bolete mushrooms known as the Gyroporus genus. There are only three species of this genus that are typically found in the midwest, one of which, gyroporus cyanescens, is relatively uncommon and, though edible, most exciting for its beautiful staining coloration. The other two species that are both fairly commonly found throughout the summer in oak forests is the much beloved “Chestnut Bolete” (gyroporus castaneus) and its red cousin gyroporus purpurinus. Both of them also happen to also be delicious.
Identification
Broadly speaking, all gyroporus fungi are small to medium sized mushrooms - typically
between a half inch and 3 inches in height, with a stem proportional to its cap (not small or dainty but not particularly thick either) and a broad concave cap sometimes becoming flattened in age. The flesh when sliced opened is white or creamy colored
and does not stain (except in the case of gyroporus cyanscens, which does stain a dramatic blue). The stems of all gyroporus mushrooms are similar the the flesh of the cap in color, but often are either hollow in the center or filled with a loose, cottony structure. All gyroporus fungi are boletes with tubes hanging from their caps as their spore disseminating structures. If you look underneath the cap of a gyroporus mushroom, all species will be indented underneath with a surface that, when young, will look almost like a white or creamy suede. For these younger specimens, the opening of the tubes on the surface underneath the cap will not easily be visible to the naked eye. For older specimens, however, the bottom of the cap will have a creamy or yellowish spongelike surface because the tubes have opened up, and though still very small <1 mm, they are typically visible. All gyroporus mushrooms have a yellow spore print. Like many boletes in North America, gyroporus mushrooms love oak forests and you will typically find them growing singly or in small troops.
Gyroporus castaneus
Probably the most well-known and beloved of the gyroporus species and commonly referred to as the “Chestnut bolete”, this mushroom is striking in appearance and flavor. When I find these, I often initially mistake them for hedgehog mushrooms, as they have a similar pale brown/tan color, with subtle hues of pink and orange, on both the cap and the stem. Again, similar to the hedgehog, they can be small or medium sized, but it would be unusual to find any chestnut boletes larger than a couple inches wide or tall, whereas hedgehogs can occasionally become much larger.
They have a rich nutty flavor that is accentuated by drying them. In my experience with gyroporus mushrooms, it is atypical to find more than just a few here or there while out hunting summer mushrooms. If you want to eat an entire meal of them, it’s best to dry them and over the course of the summer (you can find these from June through September in Minnesota), you can end up with quite the stash of these little boletes.
Gyroporus purpurinus
These beautiful mushrooms are very similar to their cousins, the Chestnut bolete, except they are a deep burgundy purplish color and they tend to be smaller than either the Chestnut bolete or the blue staining gyropore. Though it might be tempting to think these could be confused with the (in?)famous bicolor bolete, these are typically darker and smaller than the bicolor bolete. They also do not bruise blue at all. Flavorful and eye catching, I recommend sprinkling a few fresh ones to add some color to other summer mushrooms in a sauté. Of course, it would also be wise to dry these and add some to your accumulating stash of dried chestnut boletes.
Gyroporus cyanscens
Last but not least of the gyroporus mushrooms that grow in the midwest is gyroporus cyanscens. This is the largest of the three and until tampered with, I would describe it as the ugliest. It is a medium sized mushroom, probably about 3 to 5 inches tall and about 2-4 inches wide. It is often somewhat lumpy looking and thick with a white or greyish stem and cap. I know I am not selling this mushroom here, but remember: looks can be deceiving. Especially with mushrooms. If you find one of these, pick it up and slice it open and let yourself be mesmerized by the dramatic color change of the interior flesh from a creamy white or grey color to a rich and deep shade of blue. It is quite the sight to behold and this transformation alone makes the mushroom a fun find. It is considered edible, though I think not as good as the other two mentioned here and I cannot say that I’ve ever tried one.
How to use them in the kitchen?
As noted above, these boletes (like many) are considered to be best dried to concentrate their flavor and then rehydrated and added to a sauté, soup, gravy or sauce. I would use them much like any other bolete, or like morels for that matter, which I also like to dry and rehydrate for the best flavor. Because of their smaller size, it is nice to dehydrate these whole or only cut in half. This can give a more dramatic appearance in a dish as well.