Tea storage is the process of ensuring that tea maintains its original quality, based on its basic packaging. Tea leaves are highly hygroscopic and odor-absorbing, making them susceptible to absorbing moisture and odors from the air. If stored improperly, they can lose their flavor within a short period. The more delicate and fragrant the tea, the more challenging it is to preserve. Typically, after some time in storage, the aroma, taste, and color of tea will change, with the original freshness disappearing and a stale taste emerging. Therefore, mastering the storage methods of tea is essential to guarantee its quality in daily life.
The basic information includes the Chinese name for tea storage, which signifies ensuring the preservation of tea’s original quality. The nature of tea is highly hygroscopic and odor-absorbing, and improper storage methods can cause it to lose flavor quickly. Key points to consider are that tea easily absorbs moisture and odors, so special attention should be paid to whether the packaging and storage are appropriate. Packaging should be aesthetically pleasing, convenient, hygienic, and protective of the product, as well as moisture-proof and odor-resistant during storage to ensure tea quality.
The main factors causing tea deterioration include: 1. Light. 2. Temperature. 3. Tea moisture content. 4. Atmospheric humidity. 5. Oxygen. 6. Microorganisms. 7. Odor pollution. Microbial deterioration is limited by factors such as temperature, moisture, and oxygen, while odor pollution is related to the storage environment. To prevent tea deterioration, it is necessary to control light, temperature, moisture, and oxygen. Packaging materials should be opaque, such as metal cans and aluminum foil bags. Oxygen removal can be achieved through vacuum or nitrogen packaging, or by using oxygen absorbers.
Tea storage methods can be divided into ambient temperature storage and low-temperature storage based on the temperature of the storage space. Due to tea’s strong hygroscopic nature, regardless of the storage method, the relative humidity of the storage space should be kept below 50%, and the moisture content of tea during storage must be maintained at below 5%.
Based on the characteristics of tea and the causes of its aging and deterioration, in theory, the ideal storage conditions for tea are dry (moisture content below 6%, preferably 3%-4%), refrigerated (ideally at zero degrees Celsius), oxygen-free (vacuum or nitrogen-filled), and protected from light. However, due to various objective limitations, it is often impossible to meet all these conditions. Therefore, in practical operations, one can focus on the essential requirement of tea being dry and, based on existing conditions, try to delay the aging process of tea and take additional measures. The storage methods for tea in tea houses can be inspired by those used in households. The iron can storage method uses double-lid, colored tea cans supplied by the market as containers.
Before storage, inspect the container and lid for airtightness to prevent gas leakage. When storing, fill the container with dry tea, ensuring it is packed tightly and securely. This method is convenient but not suitable for long-term storage.
The Thermos Storage Method utilizes a well-insulated thermos as the container. Fill it with dry tea, packing it tightly to minimize air retention. Seal the opening with a cork stopper, apply white wax around the edge, and wrap it with adhesive tape. Due to the minimal air inside and stable temperature, this method is effective and easy to implement.
The Ceramic Jar Storage Method involves selecting a dry, odor-free, and airtight ceramic jar. Wrap the tea in kraft paper, place it around the jar, insert a bag of lime in the center, and then fill the jar with more tea packages. Tighten with cotton after filling. Replace the lime every 1-2 months. This method leverages the desiccant properties of quicklime to protect the tea from moisture, maintaining quality over a longer period, especially suitable for precious teas like Longjing and Dahongpao.
The Food Bag Storage Method begins by wrapping the tea in clean, odorless white paper, followed by a layer of kraft paper, and then placing it in a vacuum-sealed plastic food bag. Gently press to expel air, tie the bag with a soft string, and then place it inside another plastic bag, repeating the process. Finally, store it in a dry, odorless, airtight iron bucket.
The Charcoal Storage Method capitalizes on charcoal’s high moisture-absorbing properties. Burn the charcoal, cover it immediately with a fire basin or iron pot to extinguish it, and once cooled, wrap it in a clean cloth and place it in the center of a clay pot containing tea. Replace the charcoal as needed based on humidity levels.
These six methods of storing tea are suitable for home use and provide a scientific basis for tea houses to store tea. Tea houses typically have dedicated storage rooms and can use the following methods to reduce room temperature: one is the drying method, placing containers with lime or charcoal in the empty spaces of the storage room, and regularly checking for moisture in the lime, replacing it when necessary to maintain dryness. The other is using a dehumidifier, which is more suitable for storing black tea.
Storage rooms should be opened sparingly, and if ventilation is needed, choose a sunny noon to open the windows for half an hour. Upon entering the storage room, inspect for moldy tea leaves, and regularly check after storage. Remove any moldy leaves promptly, identify the cause, and eliminate negative factors. Dehumidifiers are effective only in a sealed environment, so doors and windows should be closed promptly after entering and exiting.
Using desiccants can extend the storage time of tea to about one year. The type of desiccant to choose can be determined according to the type of tea and the convenience of obtaining materials. For storing green tea, lumpy un-deliquesced lime can be used; for storing black tea and scented tea, dry charcoal can be used; if possible, color-changing silica gel can also be used.
When using quicklime to store tea, first wrap the loose tea in thin kraft paper (in packages of a few taels to half a catty), tie it tightly, and arrange it in layers around the dry, odorless and intact earthenware jar or small-mouthed iron cylinder without rust and odor. Place one or several bags of un-weathered quicklime in the middle of the jar or cylinder, then put a few small packages of tea on top. Then block the mouth of the jar or cylinder with kraft paper and cotton pads, cover it tightly, and store it in a dry place. Generally, change the lime every 1 – 2 months. As long as the lime is replaced on time, the tea will not absorb moisture and deteriorate. The method of storing tea with charcoal is similar to that of quicklime, so it will not be elaborated here. The method of storing tea with color-changing silica gel desiccant has a better moisture-proof effect. Its storage method is similar to that of quicklime and charcoal, but this method has a better effect. Generally, after storing for half a year, the tea still maintains its freshness. Before the color-changing silica gel absorbs moisture, it is blue. When the desiccant particles change from blue to translucent pink, it means that the absorbed moisture has reached a saturated state. At this time, it must be taken out and baked over a low fire or exposed to the sun until it returns to its original color, and then it can be put back into use. For other teas, classify them before storage: 1. Lightly roasted teas such as high mountain tea, oolong tea, baozhong tea, longjing tea, biluochun tea, white needle silver tip tea, oriental beauty tea, and green tea. Choose tea cans with good airtightness, aluminum foil bags, or deoxidized vacuum packaging. You can choose pc plastic vacuum cans, tinplate cans, stainless steel, or tin tea cans. Avoid direct sunlight for better results, which can prevent moisture and keep the tea from deteriorating and losing its flavor. Generally, lightly roasted and fragrant teas may ferment due to a small amount of moisture. It is recommended to brew them as soon as possible. If you can’t finish drinking them in a short time, seal the tea and store it in the refrigerator for cold storage and low-temperature preservation. 2. Heavily roasted teas such as Wuyi rock tea, tieguanyin tea, aged tea, and all kinds of Pu-erh tea. When storing heavily roasted tea, first bake the moisture in the tea a little drier, which is beneficial for the tea to be stored for a long time without deterioration. If you want the tea to stabilize and reduce its roasting flavor, porcelain jars or earthenware jars are good choices. When storing all kinds of Pu-erh tea in earthenware jars or porcelain jars, remember not to cover the lid. Cover the mouth with a cloth to allow ventilation. Because all kinds of Pu-erh tea belong to post-fermentation and need moisture in the air for fermentation and natural aging. The longer it is stored, the more mellow the taste of Pu-erh tea will become, the soup color will be bright red, smooth in the mouth, and produce saliva and a sweet aftertaste.Tea tins should be placed in a cool, ventilated place, kept dry, and away from direct sunlight. Do not store them in a storage cabinet with strange odors or together with scented items to avoid absorbing odors. An iron can or a refrigerator is sufficient for household use.
The shelf life of tea: Essentially, tea is an agricultural product. All agricultural products have a shelf life, and those that have expired and deteriorated cannot be consumed or brewed. Tea is no exception. Tea also has a shelf life, but many consumers are unaware of this, and tea merchants are reluctant to admit it. Therefore, on the packaging of many teas, the shelf life is not indicated. Most tea factories in China rely on tea-tasting experts to determine through on-site appraisal which grade a batch of tea belongs to and how much it is worth. The specified shelf life may not be very accurate. Thus, the “shelf life” has become a vague topic. Some say it is one year, some say it is half a year, and some simply do not indicate the shelf life on the packaging and keep it until the “tea flavor is completely lost”. In fact, the state has formulated tea standards based on food hygiene standards and has also set limits on the shelf life. However, the state has not formulated standards for Pu-erh tea because it is a fully fermented product and it is relatively difficult to set shelf life standards. Other teas should be strictly operated in accordance with national standards. Otherwise, after the shelf life, the tea will lose its own quality and charm. If it gets damp and moldy, it is also harmful to the human body. Of course, the shelf life of tea is related to the quality of the tea, and different teas have different shelf lives. For example, Pu-erh tea and dark tea tend to age better, and their shelf life can reach 10 – 20 years. Another example is Wuyi rock tea. The aged tea of the previous year has a more fragrant aroma and a mellow taste. Also, dark teas in Hunan, Fu brick tea in Hubei, Liubao tea in Guangxi, etc., as long as they are stored properly, not only will they not deteriorate, but the quality of the tea can also be improved. Because of these characteristics, in previous years, some people hyped up old tea. A piece of aged Pu-erh tea was even hyped up to millions of yuan. Hype is a game for businessmen. After all, tea is for people to drink. If old tea is not stored properly and deteriorates, it is also an inferior product and cannot be drunk. For example, Pu-erh tea generally requires a special storage room, with the temperature maintained at around 25 degrees Celsius and the humidity controlled at around 70%. In addition, the room should be ventilated, not placed together with items with strange odors, and the tea should be turned over once every three months. These conditions are difficult for ordinary tea lovers and collectors to meet. Usually, the shelf life of sealed-packaged tea ranges from 12 to 24 months. The shelf life of loose tea is even shorter because loose tea will absorb moisture and odors during the process of being placed outdoors. This not only makes the tea lose its original flavor but also makes it more prone to deterioration. For example, green tea is generally better when it is fresh, and its shelf life is generally about one year at room temperature.The primary factors affecting tea quality are temperature, light, and humidity. If stored correctly, these factors can be minimized or eliminated, ensuring the tea maintains its quality over a long period.
Determining whether tea is expired can be assessed through several aspects: first, by checking for mold or staleness; second, by examining the color of the tea infusion, such as whether green tea turns red or the infusion becomes brown or dark; third, by tasting the flavor, focusing on the concentration, astringency, and freshness of the tea infusion. Of course, these assessments are challenging for laymen to discern. If loose tea has been at home for more than 18 months, its production time is likely even longer, and its consumption should be approached with caution. During storage, many chemical components of tea undergo oxidation, leading to the aging or deterioration of the tea. The impact of humidity is significant as chlorophyll, which is abundant in tender tea leaves, easily loses its green color and turns brown under light and heat. Tea polyphenols are prone to oxidation during storage, causing the color to turn brown. Vitamin C is an important component that contributes to the nutritional value of tea, and its content is closely related to the tea’s quality. Vitamin C is also easily oxidized and difficult to preserve; once oxidized, it reduces the nutritional value of the tea and causes it to turn brown, losing its fresh flavor. When the moisture content in tea is too low, the tea is prone to aging and spoilage. When the moisture content is around 3%, tea is easier to store. When the moisture content exceeds 6%, or when the air humidity is above 60%, the color of the tea turns brown and darker, and the quality deteriorates. The moisture content of finished tea should be controlled between 3% and 6%, and if it exceeds 6%, it should be re-fired and dried. The influence of temperature is such that higher temperatures accelerate the aging of tea. The rate of browning increases 3-5 times for every 1-degree increase in temperature during storage. Storing tea at temperatures below 10°C can inhibit browning. Refrigerating at 20°C can almost completely prevent the aging and spoilage of tea. The impact of oxygen is that if tea is improperly stored and oxygen enters, it will speed up the oxidation process, affecting the quality of the tea. The influence of light is that light carries energy, and when tea is exposed to light, it causes chlorophyll to break down and lose color. Exposure to light during storage can affect the quality of tea and may even render it undrinkable.
