Foraging Tips for Porcini Mushrooms

How to identify, find, and pick porcini mushrooms. Porcini is an easy-to-identify wild mushroom with delicious gourmet flavor – it’s called the King of Mushrooms for a reason! Includes tips on how to dry porcini and ways to cook with them.

Porcini, Latin name Boletus edulis, are prized among wild mushrooms for their flavor. They’re richer and more mushroomy than supermarket mushrooms and also easy to identify. Known also as the cep or the penny bun, it has a rich brown skin on its cap, a sponge-like underside to the cap, and a sturdy white stem. Follow just a few identifying rules, and you can’t confuse it with anything other than what it is.

If you’re fortunate to live in an area where they grow, head out to find them between August and November. They taste delicious, and looking for them among the trees is incredibly fun. I get so excited when I spot one growing! These are my tips on foraging and preparing porcini mushrooms so that you can enjoy them not just in autumn but year-round.

Where to Find Porcini Mushrooms

Porcini grow across the northern hemisphere in the soil under conifers like spruce, pine, and hemlock, but also oak. They appear from late summer to autumn and especially love the fringes of woodland, where a treed area borders an open landscape. Things to look for when you’re foraging porcini mushrooms include:

• Stout mushroom with a thick stem and brown cap growing in the soil
• Under the cap, you see a yellowish spongey material, NOT gills
• As a beginner, avoid mushrooms that look like porcini but that have red on any part of them (could be a toxic bolete)
• As a beginner, avoid mushrooms that look like porcini but that rapidly turn blue or black when cut.
• The only mushroom that looks like a porcini and passes the rules above is the Bitter Bolete Tylopilus felleus. It won’t harm you but tastes extremely bitter. I’ve not encountered it myself, though, yet.

One sign they might be around is spotting mushrooms in the amanita family, such as the iconic red and white fly agaric. This mushroom is often pictured in children’s books and is the most iconic of toadstools.

Avoid Larger Mushrooms if Possible

The main challenges in foraging for this ‘King of Mushrooms’ are that their locations are closely guarded secrets and that mature specimens are almost always found by pests first. By pests, I mean small flies and their progeny. The little white worms you find when slicing your mushrooms are a type of maggot. If the mushroom isn’t too riddled with them, you can still go ahead and use it. I do!

You can bypass these larger mushrooms and look for the youngsters, though. Because they’ve not fully opened up, pests have a harder time burrowing in. Picking younger mushrooms also means that the larger, more mature ones can be left to spread their spores and create future generations of porcini. They’re also firmer and don’t have squishy green-yellow spores in the cap.

Porcini and other Edible Boletes

Porcini belongs to a large group of mushrooms called the boletes, and they’re the easiest to ID of all the wild mushrooms. They have similar stout stems and that characteristic spongey under-cap, though they come in different sizes and colors. Some have some very slimy caps, too! As a beginner, avoid ones that have red on them or that stain blue or black. If your bolete doesn’t have either feature, then it’s probably edible. It helps to have a good mushroom guide with you for precise identification.

You pick most edible boletes, including porcini, from late summer to autumn. Some foragers cut the stem and some pluck the mushroom from the ground. It’s personal choice. However, try to process or eat them soon after picking. If you don’t do it within a day or two, they’ll go off. If you pick a lot of them, as I did last weekend, you’ll want to preserve them quickly, and the way I’ve done it the past two seasons is to dry them in a food dehydrator.

Pick Porcini When They’re Young

Porcini can be harvested very young and at just a few inches tall. When fresh out of the ground, the flesh is almost completely white, and the mushroom can be sliced and pan-fried. As the mushroom grows older, it also grows much bigger. At this stage, the pores on the underside of the cap start elongating and turning green-yellow. It’s still very much edible but is better suited for risotto and pasta dishes since this spore part tends to become a bit slimy. Larger porcini also tend to suffer more slug and insect damage. More on that further below.

Worms in Porcini Mushrooms

Finding a large porcini is an amazing feeling. A friend found one this year that was over two feet tall! Unfortunately, there is one big issue with larger porcini mushrooms: fly larvae. Tiny ones that riddle your mushroom with holes. Slice the mushrooms, and you might not see them at first, but if you see holes, you will definitely have tiny worms inside. Don’t throw the mushroom out, though! If the damage is small, you can cut out those sections or even salvage areas that do have worms. There’s also a couple of things you can do to get rid of the worms.

The first method works very well. Prepare a saline solution of 2 TBSP salt to 1 Liter (1 Quart) of room temperature water. Then, cut the porcini into large pieces about an inch thick. Leave the pieces to float in the water for three hours. During this time, the worms will evacuate the mushrooms, and you can skim them from the surface and dispose of them. Do not empty the saltwater from the bowl until you’ve removed all of the worms. Afterward, rinse the mushrooms in fresh water, pat dry, then dry or cook with them as you wish.

The second way is to air-dry the mushrooms. Slice the mushrooms thinly and leave them to dry on a rack. After drying for two to three days, the larvae will have left the mushroom. You can brush them off and then finish drying them in a food dehydrator.

How to Dry Porcini Mushrooms

Drying porcini is easy. First, clean the stem and cap with a damp cloth to remove dirt, debris, pine needles, etc., but avoid washing the mushroom in water, or it may become slimy. The top of the cap will have brown skin that most people prefer to remove. You can do this by peeling it back with your fingers, or if that’s difficult, slice the mushroom up and pull the skin off afterward.

The slices should be relatively thin and no more than a quarter-inch thick. Lay them on the racks inside your food dehydrator and set the heat at 110°F (40°C) for two to six hours. The time will depend on how many racks you have in the unit and how thick you’ve sliced the mushrooms.

Dried Porcini Mushrooms are Versatile

Once dried, the mushrooms can be slightly flexible but light and not squishy. Allow them to cool to room temperature, then store them in a sealed container such as Tupperware or a mason jar. Kept out of the light, they’ll last at least a year or more. Probably many years, but ours never last long enough to know!

You tend to use dried porcini in cooking by reconstituting it first. Cover a handful with boiling water, and both the mushrooms and the resulting broth are delicious in risotto, pasta, and other savory dishes. You can also throw the dried mushrooms into sauces, stews, and the like, and the liquid in the food will reconstitute the mushrooms.

One way to use Porcini pieces that are small or from the less-mushroomy stem is first to dry the mushroom and then pulse it into a powder. Use the powder to make broth and sauces or flavor homemade dishes like pasta. Last year, I used porcini powder to flavor handmade porcini gnocchi, and I plan to do the same for friends this week.

More Wild Food Foraging and Recipes

I love foraging for porcini each autumn. The mushrooms are easy to identify, and the flavor is just incredible. There are other easier and safer wild foods to forage in autumn, though, and here are a few ideas to get you started.

• 6 Easy Wild Foods to Forage in Autumn
• Finding and Picking Wild Garlic
• Foraging for Wild Alexanders
• Elderberry Syrup Recipe
• Picking and Drying Rose Hips for Tea