Chemical changes of oxidation and polymerization are closely related to temperature, the higher the temperature the quicker the reactions. It was confirmed that rate of tea browning was increased by 3 to 5 times when temperature is raised by 10 ℃.
Alimentary scientific theory revealed that components in absolutely dried foods were directly exposed to the air and easily be oxidized by oxygen in the air. When water molecules were aggregated with food components by hydrogen bonding, there formed a single molecular layer, the food seemed to be covered by a protection film. When tea moisture was about 3%, this single molecular protection film was formed. So the lipids in the tea were separated from oxygen in the air and prevented from oxidization by the film. On the contrary, when the moisture content was above this level, the water played a role of solvent instead of a protection film.
Oxygen can aggregate with almost every element and form an oxidized product. But oxygen in the air is most commonly found in molecular form and therefore not very active.
Light itself is a kind of energy. Illumination can increase the energy level of the whole system illuminated and is detrimental to tea storage.
Storage of Bulk Tea
1. Quick Lime storage method
This method is commonly used in storing staples of premium teas such as Longjing Tea, Dongting Biluochun, Huangshan Maofeng. Quick lime is used as a desiccating agent to keep the tea dry and to delay the deterioration of the tea. A sealed pottery container with a big belly but small mouth is usually used.
2. Charcoal Storage Method
This method is commonly used in storing Oolong tea and sometimes Congou Black tea. Its principle and method are almost the same as quick lime storage method. The fully fired charcoal is covered with a fire pan or an earthen basin so that the fire goes out. 100 g of the prepared charcoal is wrapped in a clean cotton cloth and put in a pottery jar or an iron sheet bucket. The jar or bucket is then filled with the tea wrapped in craft paper and sealed up.
3. Vacuum and nitrogen-aerated Packing Method
This is a main storage method of famous teas for recent years, especially small packed famous teas. The tea to be stored is dried for up to three to five percent of moisture content and filled in a bag made of plastic and aluminium compound foil. The bag containing tea is then vacuumed up, refilled with nitrogen gas and then sealed.
Family storage of Tea
1.pottery Jar Storage
Feng Mengzheng described in "Kuai Xue Tang Man Lu" that a big jar with bamboo leaves at the bottom was filled with tea, sealed and placed upside down to prevent gas leaking; the tea would not turn yellow even after summer. For home storage of small quantities of tea nowadays, tea with moisture content less than 6% is wrapped in craft paper and placed inside a pottery jar. Quick lime wrapped in cloth was placed at the center of the tea packages. The quantity of quick lime depends on the quantity of tea.
2. Tin Storage Method
This method is simple and popular. The clean, commercial galvanized iron tin is widely used. To keep dry, a parcel of silica gel is put inside as a desiccating agent.
3. Plastic Bag Storage method
Due to lower cost and easy usage,plastic bags in various assortments are the most popular packing materials for tea nowadays. Storing tea in plastic bags is one of the simplest and most economical methods in home storage. It is important to choose appropriate plastic bag materials. First, plastic bags special for food packing instead of other non-food packing plastic bags should be chosen. Second, the density of the plastic materials should be higher; low-pressure plastics are better than high-pressure ones. Third, its strength should be appropriate and it is better to choose a stronger one. Fourth, it should be free of contaminants and have no holes. It is better to first pack tea with clean soft paper and then into the plastic bags.