Detailed Explanation of Gastrodia elata Harvesting, Processing and Storage Techniques

Gastrodia elata is a precious Chinese medicinal herb, and doing a good job of harvesting and processing it is the most critical step in improving the quality of commercial Gastrodia elata. At the same time, Gastrodia elata has high commercial value, so proper grading and storage of commercial Gastrodia elata are also very important. The harvesting, processing, grading and storage methods for Gastrodia elata are introduced as follows:

I. Harvesting

1. Harvesting time. The harvesting time for Gastrodia elata is generally from late autumn to early winter (that is, October to November). At this time, Gastrodia elata has stopped growing. Harvesting at this time is not only convenient for processing, but also beneficial for timely cultivation after harvest, and the yield of Gastrodia elata is high and the quality is good.

2. Harvesting method. When harvesting Gastrodia elata, be careful and meticulous, and take care not to damage the tubers. First, carefully scrape away the surface soil, take out the upper layer of fungal wood and filling material, then gently remove the Gastrodia elata, harvesting layer by layer in this way. The harvested Gastrodia elata should be classified: jianma (arrow tubers) and large white tubers need to be processed promptly, while small white tubers and rice tubers are used as seed. Small white tubers and rice tubers used as seed require special attention to proper storage to avoid seed rot. The specific storage method is: first scatter moist fine soil that can be formed into a ball by hand and crumbles when released onto flat ground, at a thickness of 5-10 cm, then place the Gastrodia elata seed in a single layer on top, and then scatter another 5 cm of fine moist soil on top. Handle the seed gently when placing it. However, storage in this way should not last too long, otherwise it will cause seed rot. It is best to carry out harvesting and cultivation at the same time, preparing new fungal wood and wood segments in advance.

II. Processing

First wash the harvested Gastrodia elata clean with water, and gently scrape off the coarse skin on the surface of the tubers with a thin bamboo strip, or scrub with a cleaning ball, then divide into 3 grades: large (over 200 g), medium (100-200 g), and small (under 100 g), soak them separately in clean water, and promptly process them using the following methods.

1. Steaming method. First place an empty steamer in a pot with water and heat over high heat until the water in the pot boils, then place the Gastrodia elata into the steamer according to large, medium and small sizes and steam them. Steam large Gastrodia elata for about 45 minutes, medium for about 30 minutes, and small for about 15 minutes, with thorough steaming being appropriate, that is, no black core can be seen when held against the light. After steaming, take them out and place them on a pre-prepared baking rack for baking, and fumigate once with a small amount of sulfur, generally using 5 g of sulfur per 10 kg of fresh Gastrodia elata. During baking, turn them frequently. The fire can be stronger at the beginning, and when baking until the tubers begin to soften, switch to a gentle fire to avoid separation layers forming in the tubers and hollow centers appearing, which would affect quality. Once blisters form on the surface of the tubers, prick them open with a bamboo needle. When baked to 60-70% dry, take them out and press flat with a wooden board, then bake again after pressing flat until completely dry, and they become commercial Gastrodia elata. Gastrodia elata processed in this way has bright color and good quality. After steaming, they can also be sun-dried, but this takes a long time and is not conducive to improving quality. They can also be sun-dried during the day and baked at night, which can save some fuel.

2. Boiling method. First bring water to a boil, then place the Gastrodia elata into boiling water according to large, medium and small sizes and boil them. Boil large Gastrodia elata for about 15 minutes, medium for about 10 minutes, and small for about 5 minutes. After boiling thoroughly, take them out and bake them; the baking method is the same as the steaming method. Using the boiling method will cause some nutrients in the tubers to leach out, so its quality is inferior to the steaming method.

III. Grading

Processed Gastrodia elata is graded according to commercial quality specifications. Prices differ greatly among different grades. Generally, it can be divided into 3 grades, with specific requirements as follows:

1. First grade. Dry goods, tubers flat and oblong, surface free of coarse skin and yellowish-white, semi-transparent, individual tubers firm, free of insect damage, free of mildew, free of hollow centers, no more than 32 per kg.

2. Second grade. Dry goods, tubers flat and oblong, surface free of coarse skin and yellowish-white, semi-transparent, individual tubers firm and uniform, cross-section horny, free of insect damage, free of mildew, free of hollow centers, 33-80 per kg.

3. Third grade. Dry goods, tubers oblong, slightly flat, some curved, surface yellowish-white or pale yellowish-brown, cross-section horny, free of insect damage, free of mildew, more than 80 per kg. This also includes those with poor color, hollow centers and broken pieces, but there must be no impurities, ash or powder, etc.

IV. Storage

If processed commercial Gastrodia elata cannot be sold promptly, it must be stored properly. The storage method is: seal it in non-toxic plastic bags or other containers that are both airtight and not easily moisture-absorbing, then store in a ventilated, dry place to prevent moisture regain and mildew, so as not to affect quality. Check and turn out to dry every 30-45 days. Processed commercial Gastrodia elata will also suffer insect damage in summer, so before early summer, combine turning out to dry with sulfur fumigation 1-2 times, which can effectively prevent insect damage.