Gastrodia elata size difference is great, especially wild gastrodia elata which not only has the big size difference, but also has high excavation damage rate. It exists great difference for steaming and drying time if the gastrodia elata are in different sizes. Compared with intact gastrodia elata, the steaming and drying time difference for damaged gastrodia elata will even be greater. Therefore,the product classification is an important procedure before formal processing. Afterexcavation, wash away mud quickly and then dry the water on the surface inventilated place. Afterwards, classify each gastrodia elata by its size. More than 150g for level 1, 100 ~ 150g for level 2, 50 ~ 100g for level 3, 25 to 50g for level 4, those gastrodia elata which are less than 25g should not be processed and be kept as seeds. Wild gastrodia elata which is less than 25g should be separately processed. Damaged and vermiculate gastrodia elata shallbe treated as a cull.
Currently gastrodia elata can be processed by steaming and boiling. It is better to apply steaming processing because the medicinal ingredient loss will be less by this method. After classifying, the gastrodia elata should be put into steamer in time. Generally speaking, level 1 gastrodia elata should be steamed over high heat for 20-30 min, level 2 for 15-20 min, level 3 for 10- 15 min and level 4 for 8- 10 min. Appropriately steamed gastrodia elata will slightly present shadow in the middle of its transparent appearance if picked up to observe in the dark. Beside, it will present a slight white core（it occupies about one fifth of the diameter of gastrodia elata) if separated to check. If excessively steamed, the drying rate will be greatly reduced. If it is transparent "snow gastrodia elata" which will be processed as a gift or for export, the coarse skin on the surface need to be stripped away in time after or before steaming.
After reshaping, the gastrodia elata not only will be more valuable with uniform and beautiful appearance, but also will be easy for drying with flat shape. The gastrodia elata should be kept in 50℃ to 60℃ temperature with appropriate ventilation for the initial drying period after steaming. If the temperature keeps too high, it will occur hollowness. If the temperature is too low and the ventilation is not good, it will go bad. If it is a sunshine day, the drying cost will be reduced by sun drying.
Take out the gastrodia elata after they are 70 or 80 percent dry, straighten them to the greatest extent and then flatten them with wood plate forcibly in order to beautify their appearance. If there is bubble on the gastrodia elata surface, you can prick it with bamboo stick and then keep drying.
After reshaping, put the gastrodia elata into the drying room again, keep the temperature at 60℃ to 65℃ and then decrease it to 50℃ gradually until the gastrodia elata are completely dried. If the temperature keeps too high when the gastrodia elata are near to dry, they will be burnt.