Detailed Guide to Shiitake Mushroom Drying Technology and Storage Methods

During shiitake mushroom cultivation, poor or delayed management, or abnormal weather with large day-night temperature differences, can easily produce deformed or inferior mushrooms (collectively called "cull mushrooms"). If these cull mushrooms enter the market directly as fresh mushrooms without processing, they fetch a very low price and sell poorly. If they are dried into dried mushrooms, their value increases and they sell well.

Raw material processing: Trim the stems of fresh mushrooms. The stem length to cut should be determined according to mushroom shape, flesh, quality and cap surface, and can be divided into three grades: de-bran, half-stem cut, and flat-stem cut. Generally speaking, shiitake mushrooms with small caps, thin flesh and long stems are best de-braned (keeping the whole stem); shiitake mushrooms with large round caps, thin flesh and loose soft texture can be half-stem cut, that is, cutting off half of the stem; shiitake mushrooms with large round caps and thick hard flesh are best flat-stem cut, that is, cutting off most of the stem and leaving only 0.5 cm. Cap size, flesh thickness, cap roundness and flesh quality have a great influence on the price of the finished dried mushrooms.

Drying method: The key is to control the temperature well during the drying process. After trimming the stems of shiitake mushrooms to different lengths, spread them on drying trays, push the trays into the drying oven, close the oven door tightly and light the fire to start drying. The initial dehydration temperature must not be lower than 30°C, and 32°C is best. Dry at 40°C-50°C for 6 hours, then stop the fire. After 1 hour, dehydrate again at 45°C-50°C for 6 hours, then stop the fire again. After 2 hours, sort the mushrooms. Finally, dehydrate at 50°C-60°C until fully dried. During drying, the temperature should not rise too quickly; the hourly temperature increase must not exceed 3°C-5°C.

During the drying process, sorting the mushrooms is also a step that must not be neglected. Because the flesh thickness varies and the moisture content differs greatly, the required drying time naturally differs as well, so after the second fire stop, each tray must be checked one by one. Those found already dried should be picked out first and put into plastic bags, while the undried ones continue to be dried. This prevents some shiitake mushrooms from becoming scorched due to over-drying, which would affect the quality of the dried mushrooms.

Storage of dried mushrooms: If shiitake mushrooms are not properly stored after drying, they easily absorb moisture again, especially in the rainy season when the temperature is high and humidity is great, making them more prone to mold and insect damage. Therefore, after drying, shiitake mushrooms should be quickly graded and put into plastic bags, and a small packet of anhydrous sodium chloride should be added to prevent the mushroom bodies from discoloring due to exuded sugars. At the same time, to prevent angoumois grain moths from laying eggs and hatching, the storage room can be fumigated with carbon disulfide for 24 hours before storage, and after the residual gas is expelled, storage can begin.