Mushrooms sold as portabellos are larger, and the gills are exposed and dark, because the mushroom is allowed to ripen after being picked. Criminis are smaller, and their gills are covered with a veil of mushroom skin. In fact, if the gills are not covered, the crimini is not as fresh as it should be. Both criminis and portabellos are more intensely flavored than their more widely used cousin, the white button mushroom.
Supplier: Bulla Mushrooms