Drying porcini

Most mushrooming expeditions yield enough fungi for a meal or two. Occasionally, one finds a huge number of mushrooms. This poses a dilemma - most wild mushrooms do not keep well, even in the fridge, so what to do with them? Preserving is the answer. (Although, if you know you are not going to have enough time to preserve them, stop picking and leave them to someone else, or to the wildlife.) The main preserving options are drying or pickling. You could also make a big batch of mushroom soup and freeze it.

Out mushrooming at the weekend, apart from some hedgehog mushrooms, chantrelles, and a cauliflower fungus, we found a lot of boletes. And I mean a lot. I cooked some of the better specimens - mostly orange birch boletes and scarletina boletes (which go a vivid blue when sliced, as hinted at by their Latin name boletus luridiformus) - and decided to dry the rest. The bulk of the mushrooms I dried were bay boletes (boletus badius). Although tasty enough, bay boletes are firmly in the culinary B-list of boletes, mostly because they tend to go mushy when cooked. They make good candidates for drying though, not least because they are often found in abundance and because they can grow to a good size. The dried porcini that one can purchase in Italian delicatessens are often actually dried bay boletes.

An elderly bay bolete

Bay boletes do tend to get worm-eaten, particularly in larger older specimens. The specimen pictured above had a cap that was about 9 inches across. Although it was a splendid thing to behold, it felt rather soft and wormy and got left in the woodland. Although the odd worm-hole does not matter when it comes to drying, avoid specimens that are full of worms. 

To prepare boletes for drying, brush off any dirt with a pastry brush. Stubborn dirt can be removed with a damp cloth. Avoid the temptation to wash the mushrooms under the tap, as the spongy gills can easily become water-logged. Once cleaned, cut the mushrooms into slices about 5-6mm thick. Use a sharp knife otherwise the flesh will tear rather than cut smoothly. Bay boletes can stain slightly blue when cut, but this disappears when dried. Cut out any areas that are worm-ridden.

Arrange the slices of mushroom on grill trays or cooling racks, so that air can circulate all round them. If you have a particularly dry sunny spot, you can try drying the mushrooms naturally. If not, dry them in the oven. Set the oven at its lowest heat, hopefully no more than 50C. Place the trays of mushrooms in the oven and leave the door ajar (this is important, otherwise condensation will build up in the oven and the mushrooms will cook rather than dry). Turn the trays around occasionally so that the mushrooms dry evenly. If you think the mushrooms are drying too fast, turn the heat off for 20 minutes or so. 

The mushrooms should be dry after about 4-5 hours, and should have a suede-like texture and be flexible, rather than hard and brittle. Take the dried boletes out of the oven, and allow them to sit and cool on their grill trays overnight and so that any remaining moisture can escape. They should fill your kitchen with a wonderful mushroom aroma.

Pack the mushrooms into clean airtight jars. They should last for up to a year if stored carefully. To use dried porcini, rehydrate the mushrooms by covering them with boiling water and allowing them to sit for about 15 minutes. The water can also be used as a sort of mushroom stock. They make a great addition to risottos and pasta sauces, and can be used to add depth of flavour to dishes using commercially grown mushrooms. They can also be added dry to stews and casseroles.