The taste of a matured oolong is really dependent not only on the original quality and skills in infusion, but also on the effects and conditions of storage.
I’ll get into details of this issue in a later article, but for now, Amuk is right. Blanch it well (in case it has not been too well stored), use a slightly higher temperature than for the tea when it was fresh, and use shorter time.
Two most common factors affecting the taste would be poor storage and over re-baking. The above two steps kind of lower the adverse effects, but in case the conditions are bad, they would not be able to help much.
