Fresh vs Dried Mushrooms: How Drying Changes What You Buy
How drying changes edible mushrooms by weight, using USDA FoodData Central values for raw, cooked and dried shiitake, plus storage notes and the difference from mushroom powders.
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Safety first. Supplements can cause side effects and interact with medicines. Read mushroom safety and interactions before you use any mushroom product.
Dried mushrooms look like a different food, and by weight they are. This page explains what changes when a culinary mushroom is dried, using shiitake because the database lists raw, cooked and dried entries for it. It is about food, not supplement powders.
The main change is water
Fresh mushrooms have a high water content, and researchers describe them as prone to texture change, microbial growth and nutrient loss after harvest, which is why they are preserved. [1] In USDA FoodData Central, raw shiitake is listed at 89.7 g of water per 100 g and dried shiitake at 9.5 g. [2]| Shiitake, per 100 g | Raw | Cooked, no salt | Dried |
|---|---|---|---|
| Water (g) | 89.7 | 83.5 | 9.5 |
| Energy (kcal) | 34 | 56 | 296 |
| Protein (g) | 2.24 | 1.56 | 9.58 |
| Fiber (g) | 2.5 | 2.1 | 11.5 |
| Potassium (mg) | 304 | 117 | 1,530 |
| Vitamin D (mcg) | 0.4 | 0.7 | 3.9 |
Values are as listed in the three entries. [2] [3] The cooked entry is a separate sample, not a measure of what cooking did to the raw one.
What that means for servings
Gram for gram, dried shiitake has about nine times the kilocalories of raw in this database (296 vs 34). [2] A fair comparison is by serving. The database lists 4 dried shiitake mushrooms as 15 grams. [2] By our arithmetic that is about 44 kilocalories, which is nowhere near 100 g of raw. Compare by the fresh weight the dried mushroom came from, and read the package for how that is stated.Storing each kind
Penn State Extension advises refrigerating fresh mushrooms in their original container or a paper bag for up to three days, because loose mushrooms can dry out and moisture in plastic can spoil them. [4] It also describes home drying in a dehydrator for 8 to 10 hours, following the National Center for Home Food Preservation. [4] The sources we read do not describe shelf life for dried mushrooms, so follow the package. More is on storing mushrooms and food safety.Dried food mushrooms vs mushroom powders
A bag of dried culinary mushrooms is a food. A "mushroom powder" sold for health reasons can be made from fruiting bodies, mycelium or grain, and its label may not match what a study used. See mushroom powders and fruiting body vs mycelium. A nutrition value for a dried food does not tell you what a powder contains, and a result for a powder does not apply to a dried mushroom in soup.Evidence and limits
Proper evidence not found that drying makes mushrooms better or worse for health. We searched PubMed for preservation reviews and USDA data and found nutrient values and technical reviews, not human outcomes. The vitamin D amount changes with UV exposure and varies by entry; see mushrooms and vitamin D.Frequently asked questions
Are dried mushrooms more nutritious than fresh?
Per gram, dried shiitake lists more of every nutrient in the table than raw, because water is gone: 9.58 g protein vs 2.24 g per 100 g. [2] Per serving the difference shrinks.
How do I compare dried and fresh servings?
Compare by the fresh weight the dried amount came from. The database lists 4 dried shiitake as 15 g. [2]
Does dried shiitake have vitamin D?
The dried entry lists 3.9 mcg per 100 g, against 0.4 mcg raw. [2]
Is mushroom powder the same as dried mushrooms?
Not necessarily. Powder products vary in species, part and form; check the label.
Can I dry wild mushrooms to make them safe?
No. Drying does not destroy their toxins. [4]
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
Safety
References
- Huo J, Zhang M, et al. New preservation and detection technologies for edible mushrooms: A review. J Sci Food Agric. 2023. Read 2026-10-22.
- U.S. Department of Agriculture, FoodData Central, Mushrooms, shiitake, dried (168436) and Mushrooms, shiitake, raw (169242). Read 2026-10-22.
- U.S. Department of Agriculture, FoodData Central, Mushrooms, white, cooked, boiled, drained, without salt (169252) and Mushrooms, shiitake, cooked, without salt (168437). Read 2026-10-22.
- Penn State Extension. Preparing and Preserving Mushrooms. Updated November 22, 2024. Read 2026-10-22.
- Boels D, et al. Shiitake dermatitis recorded by French Poison Control Centers. Clin Toxicol. 2014. Read 2026-10-22.