How to Brew Oolong Tea: Temperature, Ratio and Steep Times

To brew oolong tea well, control three things: water temperature, leaf weight and steep time. For a light, ball-rolled oolong such as Jin Xuan, use 4–5 g of leaf per 100 ml at 90–95 °C in a small gaiwan, with very short steeps. In a mug, use 1.5–2 g per 100 ml at 80–90 °C for 3 minutes. This guide explains how to brew oolong tea hot, iced and cold, and for milk tea.

What oolong is

Oolong is a partly oxidized tea, between green tea and black tea. Lightly oxidized, unroasted oolong tastes fresh and floral. Heavily oxidized or roasted oolong tastes darker and fruitier, and it takes hotter water.

Shape also changes how oolong brews:

• Rolled balls (Tieguanyin, Jin Xuan and many Taiwanese oolongs) are dense. They need heat and time to open, so later steeps are often the best.
• Twisted strips (Wuyi rock oolong, Phoenix Dancong) are bulky and release flavor fast, so steeps can be shorter.

Vietnamese Jin Xuan oolong

Jin Xuan is a tea cultivar bred in Taiwan. It is now widely planted in the Vietnamese highlands. Its natural creamy note is why it is often sold as milk oolong. Some milk oolongs are flavored. Ours is not.

Our Jin Xuan oolong is a green oolong: lightly oxidized, unroasted and rolled into small, tight green balls. It brews a bright yellow liquor with a floral, milky aroma and a light, sweet taste. Water below boiling protects that milky note.

Oolong tea brewing chart

Start with these figures for a green, ball-rolled oolong such as Jin Xuan. For dark or roasted oolong, use water at 95–100 °C.

Sources: figures based on Yunnan Sourcing (gongfu), Rishi Tea and the Tea and Herbal Association of Canada (mug), and Iowa State University Extension and Harney & Sons (iced and cold brew).

Water: temperature and softness

Hotter water extracts aroma faster, and bitterness too. This is why gongfu brewing pairs hot water with very short steeps, while a mug uses cooler water and one longer steep. Without a kettle that has temperature settings, let boiled water cool and check it with a thermometer.

Use soft, low-mineral water. If your tap water is hard, filter it or use a soft bottled water. Hard water flattens the aroma, dulls the color and can leave a film on the tea. The tea-tasting standard ISO 3103 notes that water hardness changes the flavor and look of tea. If you buy tea for a shop, test samples with your shop's water.

How much leaf to use

Weigh the leaf. A spoon of rolled balls weighs much more than a spoon of twisted strips. In a 120 ml gaiwan, use 5–6 g, roughly enough rolled balls to cover the bottom. In a 250 ml mug, use 4–5 g. If the tea tastes weak, add leaf rather than steeping longer.

Gongfu method, step by step

Gongfu brewing uses a gaiwan or small teapot of 100–150 ml.

1. Heat water to 90–95 °C. Warm the gaiwan, a small pitcher and the cups with hot water, then empty them.
2. Add 4–5 g of leaf per 100 ml of gaiwan volume.
3. Optional: cover the leaf with hot water and pour it away after 5–10 seconds. This rinse helps the balls open.
4. Fill the gaiwan, cover it and pour all the tea into the pitcher after 10–20 seconds. Drain every drop, or the leaf keeps brewing.
5. Add 5–15 seconds to each new steep. The third or fourth steep is often the best.
6. Stop when the tea tastes thin, usually after six to nine steeps.

Western method: mug or teapot

1. Heat water to 80–90 °C. Start at 85 °C. Go cooler if the tea is bitter and hotter if it is flat.
2. Put 1.5–2 g of leaf per 100 ml into a large basket infuser or a teapot. Small mesh balls are too tight: rolled oolong opens to several times its dry size.
3. Steep for 3 minutes, then remove the leaf.
4. Steep the same leaf two or three more times, adding about a minute each time.

Iced oolong and cold brew

Hot-brewed iced tea. Use 3–4 g of leaf per 100 ml of water at about 90 °C, double the mug amount, and steep for 3–4 minutes. Strain and pour over the same volume of ice. If the tea turns cloudy, let it cool for a few minutes before it meets the ice. Add sugar after brewing.

Cold brew. Steep 10–15 g of leaf in 1 liter of cold, filtered water in the refrigerator for 6–12 hours, then strain. Cold water extracts less bitterness, so green oolong comes out smooth and sweet.

Iowa State University Extension advises against brewing tea in the sun. It also advises using brewed tea within 8 hours at room temperature, or within three days in the refrigerator.

Oolong for milk tea and bubble tea shops

Oolong is a common milk tea base in Asia. Green oolong gives a light, floral milk tea, and roasted oolong gives a toasty one. Jin Xuan's natural milky note suits milk well. These rules keep every batch the same:

• Brew stronger than for plain tea, because milk, sugar and ice dilute it. Write the recipe down in grams, liters, degrees and minutes.
• Give the leaf room. Use a large mesh basket or a roomy filter bag, and stir once or twice.
• Strain on time. Leaf left in the urn turns the base bitter.
• Brew smaller batches more often. Cool them quickly and keep them cold.
• Clean and sanitize urns and dispensers every day.
• Compare suppliers fairly. Brew both teas with the same leaf weight, water, vessel and time, as ISO 3103 requires for comparative tasting.

How to store oolong

Air, light, heat, moisture and strong smells fade oolong's aroma, and green oolong fades faster than roasted. Keep it in an airtight, opaque tin or pouch, away from coffee and spices. For bulk green oolong we recommend vacuum aluminum bags (see packing and loading). After opening a bag, move the tea into small sealed tins. If you refrigerate oolong, keep it sealed and let it warm up before opening. In a shop, use the oldest stock first.

Common oolong brewing mistakes

• Boiling water and long steeps on green oolong, which make the tea sharp and bitter.
• Judging the tea by the first steep. Rolled oolong often tastes best once the balls have opened.
• Hard or chlorinated water, which hides the floral notes.

Frequently asked questions

What water temperature is best for oolong tea? For green, ball-rolled oolong, use 80–90 °C in a mug and 90–95 °C for short gongfu steeps. Roasted oolong takes water near boiling.

How many times can oolong be steeped? Three or four times in a mug, and six to nine times gongfu style.

Should I rinse oolong before brewing? It is optional. A rinse of 5–10 seconds helps rolled balls open.

Can I add milk to oolong tea? Yes. Oolong milk tea is popular, and Jin Xuan's milky note suits milk. Brew the tea stronger.

How long does brewed oolong keep? Up to 8 hours at room temperature, and up to three days in the refrigerator.

Bulk Jin Xuan oolong and samples

Goo Farm makes Jin Xuan green oolong in Vietnam and supplies it in bulk to tea shops, cafés, milk tea brands and importers. See the specification on our oolong tea page, read our Vietnam oolong tea guide, or contact us to request a bulk sample.