Detailed Explanation of Primary Processing Methods and Operating Steps for Gastrodia elata
When Gastrodia elata is sold fresh or delivered for sale, after harvest it should be kept from being bumped, knocked about, or mechanically damaged, then the soil and sand on the tubers should be gently brushed off with a soft brush, and they can be packed into soft-lined wooden boxes or plastic crates. If processing dried Gastrodia elata, it takes longer; generally the boiling method and the steamer method are used for cooking, followed by oven drying or sun drying. In actual production, the steamer method and heated kang drying method are generally used for drying, and the operational process flow is: grading Gastrodia elata -> washing with clean water -> steaming until cooked over high heat -> heated kang drying at 50°C for 60 minutes, at 60°C for 60 minutes, at 70°C for 60 minutes, at 80°C for heated kang drying until fully dried.
1. Grading. Grade by weight in 50-gram increments, that is, place and process separately those of 50-99 grams, 100-150 grams, 151-200 grams, and 201 grams and above, and at the same time remove diseased tubers, rotten tubers and other substandard products.
2. Washing. Wash the soil and sand off the surface of the tubers with clean water.
3. Steaming. Put the washed Gastrodia elata into the steamer and steam until cooked. The usual method is: after bringing the water to a boil over high heat, first put in the largest tubers, steam over high heat for about 5-6 minutes, then add the next largest tubers and continue steaming; after 5-6 minutes add the slightly smaller tubers, steam for another 5-6 minutes, and finally add the small tubers; after maintaining high heat for 5-6 minutes, generally all can be steamed cooked. During steaming, note the following: each time a new steamer tier of raw tubers is added, the original steamer tier must be lifted up and the new tier placed at the very bottom. To check whether they are cooked, the standard is that they are thoroughly cooked with no hard core.
4. Heated kang drying. For a brick or adobe heated kang, burn a high fire until the kang surface reaches 50°C, arrange the cooked tubers in a single layer, turn them once every 30 minutes, and raise the temperature by 10°C every 60 minutes; when the maximum temperature reaches 80°C, do not raise it further, and maintain that temperature until fully dried. The key points during heated kang drying are: when dried to half-dry, the tubers become very soft; gently press the tubers with a clean, smooth wooden board, the purpose being to make them flat and straight, with higher transparency, and easier to break when used, while also making them easier to measure; this work can be done along with turning the tubers during the drying process.
To increase the commercial value of Gastrodia elata, work can be started from three aspects, and the work should be done meticulously: First, strict grading. For each cooking and drying operation, use only one specification of Gastrodia elata, so as to make it easier to control the heat and the operation. Second, after washing the tubers clean, use a skin-peeling machine to remove the rough outer surface, spots and so on of the Gastrodia elata. Third, during the drying process, blisters may bulge under the skin of the tubers; a very fine bamboo needle can be used to prick them to release the air, and then they should be smoothed and pressed flat.