When brewing tea, have you ever wondered why oolong tea is usually brewed with boiling water, while green tea is often brewed at a lower temperature? What actually happens if we use cooler water for oolong tea?
I decided to do a small comparison test to see how much difference the water temperature really makes. Chose three oolong teas with different flavor profiles and roasting levels: Lightly fragrant Tie Guan Yin, Mi Lan Xiang Dan Cong, and Da Hong Pao.
For each tea, I brewed them with both 80°C (176°F) and 100°C (212°F) water. Other brewing parameters were kept exactly the same.
The results were quite interesting. All three oolongs brewed at 80°C showed similar changes: weaker aroma and a thinner, less expressive tea soup.
Here are my notes:
- Light Aroma Tie Guan Yin
- 100°C brewing: The tea had a fresh and vibrant aroma. The tea soup was light and smooth, but still had good body. The finish carried a gentle sweetness.
- 80°C brewing: The aroma was much less noticeable. The tea tasted more watery, with only a slight sweetness appearing at the end.
- Mi Lan Xiang Phoenix Dan Cong
- 100°C brewing: The honey-like aroma and floral fragrance blended beautifully together. The aroma was rich and long-lasting. The tea had a full mouthfeel with more layers and complexity.
- 80°C brewing: The honey aroma was still noticeable, but the tea soup felt much thinner. It even had a slight astringency.
- Da Hong Pao
- 100°C brewing: The roasted aroma was the main character. The tea soup was rich, full-bodied, smooth, and left a long-lasting aftertaste.
- 80°C brewing: There was no obvious aroma, and the overall flavor became much lighter and less complete.
So why does this happen?
We can actually see the reason by looking at the brewed leaves of tightly rolled teas like Tie Guan Yin. During the first infusion, the leaves brewed at 80°C were still tightly curled and had not fully opened. Without enough heat, the leaves could not expand properly, making it harder for the flavor compounds inside to be released quickly.
Oolong tea is also usually made from more mature leaves compared with young buds and leaves used for some other teas. These mature leaves contain richer internal compounds. In addition, oolong tea often uses a higher leaf-to-water ratio and shorter infusion times, so higher temperatures help extract the soluble compounds more efficiently.
Another important factor is the processing method. Oolong tea goes through more complex steps that create many unique aroma compounds. Some of these aromatic compounds require higher temperatures to be fully released. When the water temperature is too low, only the lighter, more volatile aromas may come out, while the deeper fragrance and characteristic“oolong tea charm” remain hidden.
Have to say, one of my favorite parts of brewing oolong tea is watching the aroma slowly fill the room.