Can you just place picked shrooms in the sun to dry?
Sun drying can be fairly effective, especially in dry climates, but the mushrooms will never dry completely due to atmospheric humidity.
Sun drying can be fairly effective, especially in dry climates, but the mushrooms will never dry completely due to atmospheric humidity. If you only need to preserve the mushrooms for a short time, sun-drying will prevent putrefaction. However, for long term storage you should not rely on sun-drying alone; you may wish to use it as a first step, but the mushrooms should go through an additional drying stage with a dessicant like silica gel (sold as kitty litter) or calcium chloride (sold as ice-melter) to ensure they retain maximum freshness and potency.
After the initial sun-drying period. The mushrooms should be dry to the touch, slightly shriveled and somewhat rubbery. To what degree depends on the relative humidity, as previously stated, as well as the amount of sunlight available. To finish the process, an airtight container should be used with the dessicant being isolated from the fruitbodies by a physical (but air permeable) barrier.
Calcium chloride, for example, liquifies as it locks up moisture. A large 150mm petri dish or similar container can serve to not only hold the calcium chloride as it liquifies. It can also be heated in an oven later to recycle it for the next round.