A Detailed Guide to the Correct Methods for Storing and Preserving Ginger
Ginger is the fresh rhizome of the perennial herbaceous plant ginger (Zingiber officinale Roscoe) of the Zingiberaceae family, growing 40-100 cm tall. Its other names include ginger root, bailayun, gouzhuangzhi, yindixin, yanliangxiaozi, fresh ginger, and honey-roasted ginger. The rhizome (dried ginger), the cork layer (ginger peel), and the leaves (ginger leaves) can all be used as medicine. In traditional Chinese medicine, ginger has effects such as dispersing, stopping vomiting, and relieving cough.
Ginger's Growth Habits
Ginger originated in the tropical regions of Southeast Asia. It likes warm, humid climates and has weak cold and drought tolerance. The plant can only grow during the frost-free period. The most suitable temperature for growth is 25-28°C. When the temperature is below 20°C, sprouting is slow. When frost occurs, the plant will wither, and after frost damage the rhizome completely loses its ability to sprout. In most counties of the main producing area in Guangxi, the annual average temperature is 18-19°C, the average July temperature is 25.3°C, and the extreme high temperature is 39°C; the average January temperature is 10.2°C, and the extreme low temperature is -4°C; the annual frost-free period is more than 330 days. The annual rainfall is 900-1300 mm, and the relative air humidity is about 80%.
It likes a warm, humid climate, is not cold-tolerant, fears moisture, and fears direct strong light. Avoid continuous cropping. It is best to choose sloping land and slightly shaded plots for cultivation. Deep, loose, fertile, well-drained sandy loam to heavy loam is suitable.
How is ginger stored and preserved?
Ginger Storage
For ginger used for storage, in mid-to-late November, when the aboveground part begins to turn yellow and the rhizome is fully swollen and mature, choose clear weather, harvest when the tubers are dry and free of mud, remove the stems and leaves, and discard diseased ginger, inferior ginger, and mechanically damaged ginger. The key to storage is keeping warm. Four methods are briefly introduced below:
1. Closed pile storage: Strictly select the ginger, leave the better-quality ones loosely piled in the warehouse, and cover them well with straw bags and straw curtains for storage. Then build a brick wall on the south side of the warehouse to separate a small warehouse, and coat the brick wall with mud to plug the gaps between the bricks to prevent cold wind from blowing in. Place the ginger pile inside the brick wall. The ginger pile is about 2 m high. Evenly place several ventilation tubes made of reeds into the pile up to the top to facilitate ventilation. When piling for storage, leave no gaps at the corners of the wall, and the middle can be slightly looser. After piling, immediately seal the top with mud or straw bags. The storage warehouse should not be too large; generally about 5000 kg per warehouse is suitable. The warehouse temperature is generally controlled at 18C-20C. When the air temperature drops, more covering can be added to keep warm; if the temperature is too high, the covering can be reduced to dissipate heat and lower the temperature.
2. Pit burial storage: In places with a high groundwater level, the pit burial method is mostly used to store ginger. The depth of the pit should be based on the principle of not reaching water, generally 1 m deep, with a diameter of about 2 m, wider at the top and narrower at the bottom, either round or square, and one pit can store about 2500 kg. A straw bundle is set up in the center of the pit to facilitate ventilation and temperature measurement. After the ginger is arranged, first cover the surface with a layer of ginger leaves, then a layer of soil, and later cover with soil in stages as the air temperature drops. The total thickness of the covering soil is 60-65 cm, based on the principle of maintaining suitable storage temperature inside the pile. Use straw on top of the pit to form a round pointed roof to protect against rain, set up drainage ditches around it, and set up a windbreak on the north side to prevent cold.
In storage management, both heat and cold must be prevented. In the early stage after being put into the pit, the temperature tends to rise easily, so the pit opening cannot be completely sealed. During the first month, a relatively high pit temperature should be maintained, requiring above 20C; afterward, maintaining about 15C is sufficient. In winter, it must be sealed tightly to strictly prevent the pit temperature from being too low. During storage, frequently check whether the ginger blocks have changed, and there must be no accumulated water at the bottom of the pit.
3. Mud and sand burial: The burial pit is built from bricks, stones, etc. in a warehouse or basement, about 0.8 m high and about 1 m wide, with unlimited length. When storing, first spread a layer of mud and sand about 5 cm thick with a water content of about 10% at the bottom of the pit, then place several ventilation tubes, and then place the selected ginger on the mud and sand in the pit, one layer of ginger (four or five ginger blocks thick) and one layer of mud, piling up to about 5 cm from the pit opening. Finally, cover with mud and sand so that the ginger is not exposed to the air.
During the storage period, frequently check changes in the pile temperature, and regulate it by thickening or removing the covering material so as to maintain relatively stable temperature and humidity in the storage environment. Do not turn the pile easily.
4. Air-raid shelter storage: One layer of sand and one layer of ginger, piled into a rectangular stack 1 m high and 1 m wide, each stack 1250-2500 kg. In the middle of the stack, set up a ventilation bundle about 10 cm in diameter tied from thin bamboo poles, and place a thermometer inside to measure the stack temperature. Seal the surroundings of the stack with wet sand. After sealing the stack, close the cave door well, and leave air holes above the cave to prevent cold wind from blowing in.
During storage management, one week after entering the healing period, the temperature gradually rises to 25C-30C. After 6-7 weeks, the temperature inside the stack gradually drops to 15C. The ginger changes color to yellow and has aroma and a pungent taste. At this time, the door can be opened, and it should be closed when it is cold. In the later storage stage, the temperature should be maintained at 12C-15C for a long time. After the Beginning of Spring, if the relative humidity is less than 90%-95%, some water can be sprinkled on the top surface of the stack. If sprouting occurs, it indicates that the storage temperature is too high, and ventilation can be used to regulate it; if the ginger stack sinks and has an abnormal odor, check for disease and rot.
Ginger Preservation
Cellar Site Selection and Disinfection
A newly dug cellar should be chosen in a sunny, wind-sheltered place with high, dry terrain and convenient drainage, and 4-5 m deep. For an old cellar, first remove the 2-3 cm thick old soil layer to expose the new soil layer, then spray and sterilize with an 800-fold carbendazim solution.
Ginger Harvesting and Selection
Ginger used for storage should be fully grown rhizomes, generally harvested before the first frost to avoid frost damage. If the harvested ginger is too wet with soil, it can be dried slightly, taking care to avoid excessive sun exposure. Generally, after harvest, it should be put into the cellar for storage immediately and must not be left overnight in the field. It must not be harvested in rain or after rain, otherwise it will not store well. Ginger used for storage should be strictly selected, discarding frozen, injured, small, shriveled, diseased, and rain-soaked ginger blocks, and selecting neatly sized, good-quality, disease-free, robust ginger blocks for storage.
Placing Ginger into the Cellar
Before placing, first spread a 4-5 cm thick layer of river sand at the bottom of the cellar, and stand 2-3 bundles of reed stems or corn stalks per sq m to facilitate ventilation. Place the graded ginger in concentrated stacks by grade. When stacking, arrange the ginger upright and tightly, one layer of ginger and one layer of sand, with the sand 2-3 cm thick. The top layer of ginger should be about 30 cm from the cellar top. Throughout the process, handle it gently and never bruise the ginger blocks.
Opening the Cellar to Release Heat
In the early storage stage, because the ginger blocks respire vigorously, the temperature inside the cellar is relatively high, so the cellar opening should not be completely sealed and ventilation should be maintained. In the early storage stage, the ginger is crisp and tender and easy to peel, so the temperature should be maintained above 20°C to allow the ginger to heal and age, with scars filling in evenly and no further peeling. Shading objects need to be placed at the cellar opening to prevent sunlight from shining in.
Gradual Cellar Covering
When the temperature inside the cellar drops to about 15°C, place a layer of crop straw on the surface of the ginger to prevent cold wind from harming the ginger during open-cellar inspections. First cover the cellar opening with straw, and as the air temperature drops, gradually increase the thickness of the pressed soil until it is tightly sealed. If necessary, also set up straw curtains to block the wind.
Temperature Control
Storing ginger has very strict temperature requirements. Ginger likes a warm, humid environment and is not tolerant of low temperatures or cool conditions. Below 10°C it will suffer cold damage. The most suitable temperature for storing ginger is 15-18°C. When the temperature inside the cellar is above 20°C, ventilation should be strengthened.
Humidity Control
Hang a wet-and-dry bulb thermometer in the cellar, regularly check the temperature and humidity inside the cellar, and control the humidity inside the cellar at about 95%. When the humidity is below 90%, ginger easily loses water and shrivels; when the humidity is too high, it easily causes ginger blast.
Pick Out Diseased and Damaged Ginger Blocks
During cellar inspections, pick out moldy and rotten ginger blocks from the cellar at any time to prevent the spread of pathogens. At the same time, pick out the ginger blocks around the diseased ginger and store them separately, and carry out disinfection treatment.