Key Points and Detailed Methods of Dried Shiitake Mushroom Production Technology

1. Harvesting standard. For shiitake mushrooms intended for drying, the fruiting body has grown to seven or eight tenths maturity, and when the edge of the cap is still curled inward in the shape of a gong rim, this is exactly the suitable harvest time. It is best to harvest shiitake mushrooms on sunny days. Before rainfall, if the mushrooms have already approached the harvest period, harvest them before the rain.

2. Harvesting method. The principle is not to damage the original substrate and to keep the mushroom body intact, attractive, and of good quality. When picking, hold the mushroom stem tightly with the thumb and index finger, and rotate left and right to separate the stem base from the substrate. Do not pull upward with force, so as to avoid lifting up the entire block of substrate. After fresh mushrooms are picked, they should be placed in small bamboo baskets or small baskets, lined with plastic or gauze. Place them gently, and do not squeeze the mushroom bodies. When harvesting, also note that the hands may only touch the mushroom stems, and must not scrape the gills, the caps, or the edges of the caps. After harvesting, the fruiting bodies should be graded promptly, placed one by one in baskets or small baskets lined with gauze, and processed in time.

3. Drying methods. (1) Sun-drying method: place the sorted fresh mushrooms with the gill side facing up on a bamboo mat or bamboo sieve, and dry them in the sun; they will be ready in 3 to 5 days. Alternatively, thread a string through the shiitake stems, string them one by one, and hang them in the sun to dry. However, sun-dried shiitake caps tend to warp upward, lack luster, and have no fragrance, and this method is also limited by the weather, so it is rarely used. (2) Baking basket roasting method. This is suitable for small-scale specialized households. The baking basket is woven from thin bamboo strips, about 90 cm high, with a mouth diameter of about 60 cm, and has a support rack in the middle, placed 30 cm from the mouth. The outer part of the baking basket is woven with double layers of thin bamboo strips, with old newspapers sandwiched in between for insulation. Below, a stove is used with charcoal fire. When loading into the basket for baking, it is best to add a layer of ash on top of the charcoal fire so that the charcoal fire has no smoke and no tongues of flame. Control the temperature at about 40°C and roast over gentle heat. Before roasting, sun-dry for a few hours first, then place in the baking basket for roasting, which can save fuel and shorten the roasting time. (3) Drying method. Shiitake roasting can be carried out in a drying room or a drying machine. When roasting in a drying room, the heat source must be separated from the shiitake mushrooms. Before the shiitake mushrooms are put into the drying room, they should first be spread separately on drying sieves according to differences in mushroom body size and degree of dryness or moisture. When spreading the shiitake mushrooms, the caps should face upward, spread evenly, and not overlap one another. When the drying sieves are put on the racks, place small mushrooms on the lower layer and large mushrooms on the upper layer, and place those with lower moisture content on the lower layer and those with higher moisture content on the upper layer. The roasting temperature generally starts at 30°C, rises by 1 to 2°C per hour, and when it rises to 60°C, then drops to 55°C. During roasting, the evaporated water vapor should be removed in time. When they are four or five tenths dry, each mushroom should be turned over one by one. After the shiitake mushrooms shrink in size, the mushrooms on the upper layer should be merged into the lower-layer sieves, and then fresh mushrooms should be placed in the empty upper-layer sieves for roasting. The time required for shiitake mushroom drying is 4 to 5 hours for small shiitake mushrooms, 5 to 10 hours for medium mushrooms, and 10 to 12 hours for large mushrooms. (4) Combined roasting and sun-drying. Arrange fresh shiitake mushrooms on a bamboo sieve without overlapping, place them in the sun until half dry, then switch to gentle heat and roast until completely dry. When roasting, first roast at 35 to 45°C for 5 to 6 hours, then at 50°C for 3 to 4 hours, and finally at 60°C for 4 to 6 hours. Turn them frequently during roasting. When they are eight tenths dry, take them out, air-dry them in the sun for 1 to 2 days, then put them into the drying room again and continue roasting at about 45°C until the mushroom bodies are dry.