About the freshness loss of high mountain Oolongs

Spring 2017 Qilai mountain Qingxin Oolong

David in NYC wrote me the following:

"I have noticed something with green oolongs: If the package has been opened for more than 2 weeks, the flavor starts to change even if the package has been sealed tightly and has an oxygen absorber. After 3-4 weeks the flavor of the tea degrades a lot and it loses all of the subtleties that made it high quality. Have you noticed this as well and do you have any suggestions to preserve the flavor longer? 

One experiment I thought I could try was exposing the tea to humidity similar to puer, hoping that the tea would "wake up.""

My answer:

Green Oolongs are also called fresh Oolongs for a good reason: what is fresh and young rarely stays that way very long! Actually, if your fresh tea has a strong aroma that stays the same for a long, long time, this would point to an artificially flavored tea! Since these Oolongs have not been roasted, their moisture content is higher and causes changes in aromas when it's exposed to air (water + air + organic material = oxidation). Adding humidity, like for puerh, would actually make things worse! So, it's normal that these Oolongs would be less stable than roasted Oolongs. This raises several issues:

1. To preserve the fresh flavor longer, it's important to close the bag/foil tightly and minimize the air inside. Ideally, one would have a vacuum sealer! Then keep it in a rather cool, dark and clean place. (Not the fridge, as there are too many smells there). Another tactic is to drink one fresh Oolong at a time. Only open the next package when you've finished the open one(s). Or drink them fast enough within the time frame you've observed. Some pewter tea caddies can also help preserving the fresh feel of Oolong.

2017 spring Qilai mountain Qingxin Oolong 

2. Not all fresh Oolongs are processed the same. Even if they don't go as far as roasting them, the better high mountain Oolongs are well dried and come with a slightly higher oxidation level. Quality isn't just limited to the freshness level. This refining of the rough tea (maocha) helps not only to make the Oolong stable for a longer period of time, but also to give it a better aging potential.

3. The change in aromas is part of life. Let's embrace it! A well aged high mountain Oolong can be very delicious, especially the better ones, those that were well dried and were sufficiently oxidized (the others are sometimes called 'nuclear green'). Such Oolongs can even be kept in porcelain jars. Their scents will change and progressively loose freshness, but the taste and aftertaste will become smoother, but still powerful. And sometimes the change in scents even becomes positive as it adds complexity and richer aromas! But it's also a matter of managing your expectations, of course. Instead of hoping to freeze the aromas in time, expect them to change and realize that what you may have lost in terms of freshness, you might have gained in terms of finesse, elegance, depth. Also, the taste shouldn't change that much, and if the aging is well done using my (best) Oolongs, it should taste even better!

I hope this helps!