Foraging and Picking Porcini Mushrooms Safely and How to Dry Them

How to ID, forage for, and pick Porcini mushrooms, an easy to identify wild mushroom with delicious gourmet flavor. Also tips on how to dry and cook with them.

Porcini, Latin name Boletus edulis, are prized among wild mushrooms for their flavor. They’re richer and more mushroomy than any conventional mushroom and also extremely easy to identify. Known also as the cep or the penny bun, it has a rich brown skin on its cap, 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 else other than what it is.

If you’re fortunate to live in an area where they grow, head out to find them between September to November. They taste delicious and it’s fun to look for them among the trees. Here are more tips on foraging and preparing porcini mushrooms.

Where to Forage Porcini Mushrooms

I made a full video showing how I find porcini, and you can watch it just above. They grow across the northern hemisphere in the soil under conifers like spruce, pine, and hemlock, but also oak. They appear from in late summer to autumn and especially love the fringes of woodland, where a treed area borders 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
• Avoid mushrooms that look like a porcini but that have red on any part of them (could be a toxic bolete)
• Avoid mushrooms that look like a 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 extemely bitter. I’ve not encountered it myself though, yet.

One sign that they might be about is spotting mushrooms in the Amanita family such as the iconic red and white fly agaric. This is the mushroom you’ll see pictured in children’s books and is often referred to as the most iconic of Toadstools.

Avoid larger mushrooms if possible

The main challenges in foraging for this ‘King of Mushrooms’ is that locations where they grow are closely guarded secrets and that mature specimens are almost always found by pests first. I say pests to not creep anyone out. In fact, the little white creatures 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 – just try to remove any creepy crawlies first.

You can of course bypass these larger mushrooms and look for the youngsters. Because they’ve not fully opened their gills up to the air, 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.

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 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. Use both the cap and stem within a day or two or 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 four to six inches in height. When they’re this 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 risottos 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, and that is fly larvae. Tiny ones that riddle your mushroom with holes. Slice the mushroom 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 are two things that you can do to rid your porcini of worms and make it clean for eating and drying.

The first method works a treat. 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 mushroom 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 freshwater, 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 two to three days of drying, the larvae will have left the mushroom. You can brush them off and then finish the drying in a food dehydrator. There’s more information on ridding porcini of worms over here.

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 40°C / 110°F for between two to six hours. The length of 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 a little flexible but light and not squishy to the touch. 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.

You use dried porcini in cooking by reconstituting them first. Cover a handful with boiling water and both the mushrooms and the resulting broth are delicious in risottos, pasta, and other savory dishes.

One way to use Porcini pieces that are small or odd, or from the stem is to first dry the mushroom and then pulse it into a powder. Use the powder to make broth, sauces, or flavor homemade dishes like pasta. Last year I used porcini powder to flavor handmade Gnocchi and I have plans to do the same this week for friends. Here’s the recipe if you’d like to try it out too.

More Wild Food Foraging and Recipes

Foraging for porcini is something that I love doing 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
• See more about finding porcini over here.