Fresh mushrooms are ~90% water and decline within days, so preserving is essential for any haul. FRESH: store unwashed in a paper bag in the fridge (never sealed plastic, which traps moisture and turns them slimy) for 5–7 days. DRIED: the classic for porcini, shiitake, morels, and black trumpets — slice evenly, dry low (a dehydrator at ~45–55°C or a warm airy spot) until cracker-crisp, store airtight with a desiccant. Drying actually deepens flavor: in shiitake it boosts guanylate, and rehydration liquid becomes a potent stock — keep it. FROZEN: mushrooms freeze poorly raw but beautifully cooked, so dry-sauté first to drive off water, cool, then freeze flat; drop straight into a hot pan from frozen. PICKLED: quick-pickle firm species in seasoned vinegar for a bright condiment. CONFIT: slow-cook submerged in oil for a rich, spoonable larder staple — refrigerate. Salting (layering in salt) is a traditional Eastern European method for milk caps and boletes.