A Tea Box: The Storage of Tea

I found this little tea tin on a shelf tucked in a corner of an antique store. The intense colors on the box caught my eye. It appeared to be old, and the tea inside seemed to be original to the box. Unfortunately, the tea box-tea tin was not airtight, and the tea smelled of perfume. What a tea is stored in has the potential to preserve the longevity of the tea, or can cause rapid deterioration of the tea.

Enemies of Tea

There are three enemies of tea. They are light, heat, and moisture. All three external factors, singularly, can adversely affect the preservation of a wonderful tea. The three factors together (light, heat, moisture) can turn an aromatic, flavorful tea into an insipid, rancid, moldy, musty, dusty, or “gone off” tea. Simply stated “gone off tea” means it has missed the peak of freshness; the tea is stale tasting, or flat in flavor. Storing tea correctly is paramount to locking in flavor and aroma profiles. The flavor profiles which enticed you to buy the tea in the first place, can be detrimentally changed by poor storage. Let’s first examine several key points as to why light, heat and moisture are enemies to tea. Followed by a scrutinization of problematic and correct storage of tea.

Light

Tea leaves, while on the Camellia Sinensis plant, need light to assist in the development of beneficial chemical reactions within the leaves. For example, the plant uses sunlight to convert carbon dioxide into organic compounds via the process of photosynthesis. 

Sunlight or direct light radiating onto processed tea leaves is a very different matter. Light exposure can adversely affect tea leaves by fading the color of the leaves. In addition, light can raise the temperature of processed tea leaves. When manufactured tea leaf temperature rises, mold can occur on the tea leaves.

Heat

Heat is applied to tea leaves during the manufacturing process to stop the oxidation of leaves. Applying varying amounts of heat to the tea leaves enhances or deemphasizes specific flavor and aroma profiles that a tea master desires in the tea. For instance, steaming green tea leaves generally brings out a more vegetal, spinach, grassy, and sweet aroma and flavor profile in Japanese green tea. Conversely, pan firing green tea leaves will generally bring out a more buttery, nutty, creamy and slightly asparagus aroma and flavor profile in Chinese green teas. 

Heat applied to already manufactured tea leaves results in negatively affected tea flavor and aroma profiles. Heat exposure can cause a flat (uninteresting), lifeless tea flavor profile. High temperature exposure, sustained for a duration of time, will cause the tea to mold.

Moisture

Tea manufacturers decrease tea leaf moisture throughout the various stages of tea leaf processing, to a final moisture content of approximately three percent. This low moisture content in the leaf prevents degradation of tea leaves, specifically in the stages of packaging and transport. Tea leaves are hygroscopic; they will absorb moisture. 

Processed tea leaves with a moisture content over approximately four percent can potentially undergo detrimental changes. Additional moisture in the tea leaves can cause mold, and bacteria to grow. An increased moisture content in the tea creates unfavorable changes in the chemical components of the tea. The chemical changes negatively alter the flavor profile, causing the tea to lose its freshness and taste different.

Storage

Poor storage of tea can lead to tainted, destroyed, or prematurely aged tea. There is a minefield of tea storage problems that can occur. Storing wet leaves, erroneous handling of tea leaves, and a lack of attention to the tea leaves take their toll on the leaves. As tea purchasers and consumers, we have control over these aspects. Let me explain. Storing wet leaves can occur if using a wet tea scoop. The wet tea scoop is used to retrieve the leaves for steeping. Moisture has then been introduced into the dry leaf storage container, thus placing in peril the low moisture content of the leaves. Poor handling of leaves is also a variable that consumers do have control over. When handling tea leaves, hands and tea accoutrements should be free from fragranced soap residue. Lack of attention to tea leaves could lead to improper storing of the tea leaves. This could include the introduction of light, heat, and moisture to the dried tea leaves. Dried tea leaves act as a sponge. Not only are the leaves hygroscopic, but they soak up neighboring aromas that are in close proximity. 

The ideal temperature for storing tea is between forty to eighty degrees Fahrenheit, with an optimal storage temperature between sixty and seventy degrees Fahrenheit. Storing tea away from spices and off the back of the stove is another way to ensure the longevity of the tea. Teas should not be stored in a refrigerator. Ideally tea should be stored in a non-glass container. The exposure to light does affect the tea leaves. I have had to periodically use glass jars to store tea in, and have made sure to keep the tea in a dark or dim location. Porcelain is a less porous material than metal, or wood, thus creating one of the more successful materials to store tea in. Porcelain blocks light, and neighboring aromas, from permitting through to the tea leaves. 

One tea in particular is very susceptible to adverse storage. Pu’erh tea is considered alive due to microbes from the fermentation of the tea. The correct storage for Pu’erh is in a temperature controlled area, with consistent humidity, and suitable air flow. Pu’erh tea needs to be stored in very little light, and in an odor free environment. Pu’erh can be stored in Ying Ching clay containers to allow for proper air flow and proper aging of the tea. 

The Tea Box - Tea Tin

I was delighted to find this beautiful box in an antique store. It was tucked away in a corner, nearly out of sight. The outer cardboard box, the tea tin, and the tea leaves have been a treasure to me. I wanted to learn more about this tea treasure. I decided to send pictures of the tea tin to a scientist whose interest lies in dating old tea and tea objects d’art. Their best guess, by only looking at photos of the box and the tea inside it, is that it appears to be roughly one hundred years old. The tea in the tin includes broken black leaves, and long twisted black leaves. By my visual examination only, the tea appears to be a twisted leaf Oolong. 

I have not cupped the tea for several reasons. The first reason is because it appears to be a very old, grayish in color, musty smelling tea. I do not know the history of this tea, the chemical properties and the age of the tea, nor how the tea was stored. I do not want to become ill after cupping the tea. Traces of mold, or bacteria from improper storing, and metal contaminants from the metal storage container could possibly be found in the tea. In addition, the tea leaves, acting as a sponge, have absorbed a very floral, perfume aroma. The perfume aroma could be due to the chemical breakdown of old Oolong leaves. Or, most likely, the perfume aroma centers on improper storage of the box having been placed next to fragrant items. 

The more important reason that I have not cupped tea lies in the fact that a museum is showing interest in studying the tea leaf contents and the tea box. There is very little tea inside the tin box and if I needlessly cup the tea, it would not be available for scientific study. The museum has the accurate testing platform to correctly date the tea, and the box. I am very excited to learn that my treasure hunt purchase might be able to help scientists and historians. By delving into the history of the tea box, scientists could better learn the indigenous customs, and cultural heritage of tea consumption and tea manufacturing practices of long ago. 

Please be kind to your tea by storing it away from light, heat, and moisture.

-Leslie

About the Author

Leslie Sundberg is a World Tea Academy Certified Tea Specialist, a World Tea Academy Apprentice Tea Sommelier, a Specialty Tea Institute Levl IV trained Tea Specialist, and a Tea and Business Etiquette Specialist. On any given day, Leslie can be found teaching, speaking or sharing in the joys of a cup of tea.  No matter what Leslie is doing or where she is, one thing remains constant: 4:00 in the afternoon is tea time!






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