Friday, May 12, 2006

The shelf life of Oolong

Green or Black? Now there is white. What about Oolong? What’s the point? Well black tea is called black tea in Mandarin, so I often find myself explaining just what it is westerners are doing by calling red tea black. “Black tea” sounds so bad when stated in Mandarin. It gives one an impression of immanent badness. So they call it “red” instead. There is some very remarkable red tea in Taiwan called Number 18, and it is grown near Sun Moon Lake
Green Tea is referring to tea that has not been allowed to oxidize. Oolong is semi-oxidized and black tea is fully oxidized. Typically, the greener the tea, the shorter the shelf life. In tea processing, the point at which oxidation is called to a halt, is the point that determines just how red your black tea will be. In Taiwan, they have taken the process of tea processing past the normal standard of transforming a tea leaf into a consumable product to an art form.
Green Tea is best is consumed within 3 months of production. This time can be extended if refrigeration is used. Green tea should be consumed within the year of its production regardless.
Oolong, the partially oxidized tea comes in a wide range of flavors and shades of green and red. The range and quality of oolongs produced in Taiwan is startling. From Wen Shan Bao Zhong, to Formosa oolong, from Dong ding roasted oolong to the Shan lin xi greens. And never should we leave of the favorite green of all, the li shan green.
Li Shan is an area that is very well known for its agriculture. In Fact, Li Shan means Pear Mountain. In order to give the newly retired soldiers something to do, the KMT allocated land in the Li Shan area. The result was great produce. Not only did the area produce tremendous fruits and vegetables, it also grew some pretty outstanding tea.
Oolongs production resembles an art more than a science. There is no “best way” that will work in all situations. Many adjustments must be made depending on the tea at the moment of picking. Just as a great chef starts with raw ingredients, tea artisans in Taiwan start with a waxy, shiny, thick stem robust camellia sinensis leaf. Through the oolong making process, step by step, moisture is removed from the tea leaf. The steps of production include; 1) picking, 2) sun drying, 3) indoor drying / withering / tossing and bruising, 4) oven drying (sha qing / killing the green), 5) rolling, 6) baking and 7) packaging.
Oxidation happens in step three. Nowadays letting the tea oxidize is less common than in the old days. There are a few reasons for this. One is the improvement of packaging equipment such as aluminum coated bags and vacuum seal machines. These devices add to the shelf life of a greener oolong, making oxidation less essential than before. In the absence of these devices, oolong, the finished product, was often wrapped in paper. There was no air tight seal added to preserve the tea, so tea artisans had to depend on oxidation if they hoped to create an oolong that would be able to hold its flavor long enough to reach the end user and be consumed. Another reason that nicely oxidized teas are harder to find is that consumers are buying lightly oxidized oolongs at top dollar. This is a trend that started in Taiwan. Letting a tea oxidize is a risky and time consuming process that requires a good amount of experience and very keen senses. It is risky because if all conditions are not right, the entire batch of tea will be less than desirable and thus difficult to sell. Since consumers are happy to pay top dollar for tea that has only been lightly oxidized, many tea producers are choosing to minimize this step in the process.
Baking is a very important step in an oolongs production and is also one that increases an oolongs shelf life. Oolong can be lightly baked or heavily baked. Usually very high elevation green teas that are produced in optimal conditions will be baked very lightly. This tea is often best when oxidized and baked just enough to seal the flavors in. Often, teas that are harvested at non optimal times, such as fall harvest are given a heavier bake. When done well, baking can immensely improve an oolongs flavor. Baking covers up some of a tea’s less desirable characteristics by bring out some flavors that are buried deeper inside the tea. These flavors are citric in nature. Often I notice that my favorite oolongs leave a nice dusty coat of flavor particles in my mouth that lead my sense of taste on a wild adventure, trying to keep up with its constant evolution.
A heavy bake extracts more moisture from the tea. With less moisture in the tea, the tea is less likely to change. Therefore, a heavy bake will ensure the stability of a teas flavor for a greater time span.
In review, there are three steps in the oolong production process that ensure stability of flavor over time. These include oxidation, baking, and packaging. In addition to these three steps, there is also the issue of storage. Tea, properly stored will last much longer than tea that is not. Proper storage means, no exposure to sunlight, minimal changes in humidity and temperature, and relatively low temperatures.
When referring to an oolongs shelf life, there are many factors to consider. There is a certain amount of moisture still in the tea leaf, more with lightly oxidized lightly baked oolongs and less for the opposite. This moisture content will cause the tea to change over time. Teas that have been given a finish that will extend the natural shelf life should develop more slowly into an old tea. Regardless, a tea changes over time. The only way to know is take it out and drink it, now it might not be the right time, but it will continue to change. Constantly changing ever so slowly, we may take a tea out every five years and give it a try. It will certainly be different, but will it be ready? There is always the chance that the tea will change in a bad way. If this happens, there is no choice but to wait another 3 to 5 years to try the tea again, with the hope that it has taken a change for the better. Thus, when we find a appropriate flavor, it is best to drink it up rather than waiting for it to become even older.

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