Oolong: A Spectrum Rather Than a Category
Oxidation and roast are two independent dials, and oolong occupies the whole space between them.
Oolong is the least well-defined tea category and the most interesting for that reason. It occupies everything between green tea and black tea, and the range within it is wider than the range between any other two categories.
Two Independent Variables
Oxidation is the enzymatic browning allowed before fixing, ranging from around ten percent to around eighty. Roasting is a separate, later process applied with heat over hours or days, which develops entirely different characteristics.
A tea can be lightly oxidised and heavily roasted, or heavily oxidised and unroasted. Understanding both dials explains why oolongs vary so much.
| Oxidation | Roast | Character | Style |
|---|---|---|---|
| 10-20% | None | Floral, creamy, green | High mountain rolled oolong |
| 20-30% | Light | Floral with warmth, buttery | Lightly roasted rolled oolong |
| 30-50% | Medium | Stone fruit, honey, mineral | Rock oolong styles |
| 50-70% | Heavy | Caramel, toast, dried fruit | Traditional roasted styles |
| 60-80% | Light to none | Ripe fruit, honey, close to black | Eastern Beauty style |
The Rolled Styles
Many oolongs are rolled into tight balls during processing, which protects the leaf and slows ageing. These expand dramatically in water — five to eight times their dry volume — and require room and multiple infusions to give what they have.
The first infusion from a rolled oolong is frequently light, because the ball has not yet opened. The second and third are usually the strongest, and a good one continues giving for eight or more.
Brewing rolled oolong
- Use a vessel the leaf can expand in; the dry leaf should cover the base one layer deep.
- Rinse briefly to wake the leaf.
- Water at 90 to 95 degrees for lighter styles, boiling for roasted ones.
- First infusion 20 to 30 seconds, then increase gradually.
- Expect the peak around the second to fourth infusion.
A high mountain oolong that has properly opened smells of gardenia and cream. It is one of the most distinctive aromas in tea and it takes two infusions to arrive.Lian Ashworth
Roasting
Roasting is applied after processing, traditionally over charcoal for many hours, sometimes repeated over several years. It caramelises sugars, reduces green notes and produces depth, warmth and a longer-lasting character.
Heavy roasting also masks the leaf's original character, which is why it has historically been used both to create a desirable style and to improve mediocre material. Both uses are legitimate and the results differ considerably.
Ageing
Roasted oolongs can be aged, and traditionally are, sometimes with periodic re-roasting. Over years the roast character mellows and integrates, producing a rounder, smoother tea with dried fruit and medicinal notes.
- Unroasted green oolongs do not age well; drink them fresh.
- Medium and heavily roasted oolongs improve for years or decades.
- Storage must be dry and free of odours; oolong absorbs surrounding smells readily.
- A tea that has developed a sour or musty note has been stored badly rather than aged.
Regional Styles in Brief
The main producing regions each have characteristic approaches. High-altitude Taiwanese oolongs tend toward light oxidation and floral creaminess. The rock oolongs of Fujian emphasise mineral character and medium roast. Southern Fujian styles are typically lightly oxidised and intensely aromatic. Guangdong styles are known for exceptional aromatic complexity.
These are tendencies rather than rules, and producers in each region make teas across the spectrum.
Buying
- Ask about oxidation level and roast; a good seller will know both.
- Ask about harvest date; light oolongs are best fresh, roasted ones tolerate age.
- For rolled oolongs, look at how tightly and evenly rolled they are.
- Smell the dry leaf; it should be clearly aromatic even before brewing.
- Buy small quantities of several styles before committing to one.
The best value in tea
Oolong gives more infusions than any other category except puerh, which means the cost per cup of an apparently expensive tea is frequently lower than a cheap tea brewed once. Ten infusions from six grams is entirely normal.
Where to Start
A lightly oxidised, unroasted high mountain oolong shows what the category can do aromatically and is immediately appealing. A medium-roasted rock oolong shows the other direction. Trying both, gongfu style, on the same day is the fastest way to understand the spectrum.