Green tea brews best at around 70 to 80°C, oolong at around 85 to 95°C, and black tea at 90 to 100°C. White tea sits between green and oolong at roughly 75 to 85°C, while herbal infusions and pu-erh can take water straight off the boil.
Those ranges exist because temperature controls which compounds leave the leaf and how quickly. Water that is too hot pulls out bitterness and astringency before the sweeter, more aromatic flavours have a chance to develop. Water that is too cool leaves a cup that tastes thin and flat. Getting the temperature right is often the single biggest improvement you can make to tea at home, and it costs nothing if you know a few simple tricks.
Why Temperature Changes the Taste of Tea
Tea leaves contain several groups of compounds that dissolve at different rates. Amino acids, particularly L-theanine, give tea its sweet, savoury and rounded quality, and they dissolve readily even in cooler water. Catechins and other polyphenols provide body and the drying, slightly bitter sensation known as astringency, and they are extracted far more quickly as the temperature climbs. Caffeine behaves in a similar way.
Delicate teas that are less processed, such as green and white tea, have a higher proportion of those easily extracted bitter compounds and fewer of the deeper flavours created by oxidation. Hot water overwhelms them. Fully oxidised black tea has already converted much of its catechin content into other compounds during processing, which is why it stands up to boiling water and needs the heat to release its full flavour.
In short, the less a tea has been oxidised, the cooler the water it usually wants.
Green Tea: 70 to 80°C
Most green teas brew well between 70 and 80°C with a steep of one to three minutes. Chinese green teas such as Dragon Well (Longjing) sit comfortably around 75 to 80°C. Japanese sencha does well at around 70 to 80°C.
Some Japanese shaded teas go much cooler. Gyokuro, which is grown under shade to boost its amino acid content, is traditionally brewed at 50 to 60°C to bring out its intense savoury sweetness. Matcha is whisked rather than steeped, usually with water around 70 to 80°C.
If your green tea has always tasted grassy and bitter, water that is too hot is the most likely cause, followed by steeping for too long. Try dropping the temperature before changing anything else. Many green teas can also be steeped two or three times, with the water a few degrees hotter or the steep a little longer for each round.
Oolong Tea: 85 to 95°C
Oolong covers a wide spectrum, from lightly oxidised, floral teas that are close to green tea to heavily oxidised, roasted teas that are closer to black. The water temperature follows that spectrum.
Lighter, greener oolongs such as many Taiwanese high mountain teas and jade Tieguanyin brew well at around 85 to 90°C. Darker and roasted oolongs, including Da Hong Pao and traditional roasted Tieguanyin, usually suit 90 to 95°C and can take water just off the boil.
Oolong is often brewed gongfu style, using a small teapot or gaiwan, a generous amount of leaf and a series of short steeps of 20 to 60 seconds. In that style, hot water works well because the short contact time limits bitterness. If you brew oolong in a large pot with a longer steep of three to five minutes, err towards the lower end of the range.
Black Tea and Other Teas: 90 to 100°C
Black tea needs hotter water to release its full malty, fruity or brisk character. Water between 90°C and a full boil, with a steep of three to five minutes, suits most black teas, including breakfast blends, Assam and Ceylon. More delicate black teas such as Darjeeling, particularly first flush, can be brewed a little cooler at around 85 to 90°C to protect their lighter, floral notes.
White tea is gentle and does best at around 75 to 85°C, often with a slightly longer steep of three to five minutes. Pu-erh, especially the darker ripe style, is brewed at or near boiling, and a quick rinse of the leaves with hot water first is traditional.
Herbal infusions such as peppermint, chamomile and rooibos are not made from the tea plant at all. They generally need freshly boiled water and a steep of five minutes or more to extract their flavour properly.
How to Get the Right Temperature Without a Thermometer
A kettle with adjustable temperature settings is the simplest way to brew consistently, but you can get close without one.
The most reliable method is mixing. Combining boiling water with room temperature water lowers the temperature predictably. As a rough guide using tap water at around 20°C, three parts boiling water to one part cool water gives roughly 80°C, and two parts boiling to one part cool gives roughly 73°C. Pour the cool water into the cup or pot first, then add the boiling water.
Pouring between vessels also helps. Each transfer from kettle to jug to pot takes several degrees off, which is why pre-warming a teapot matters for black tea and why pouring into a cool jug first suits green tea.
Simply waiting a few minutes after the boil works too, but the rate of cooling depends on how much water is in the kettle and what it is made of, so it is less consistent.
Other Details That Affect Your Cup
Water quality matters almost as much as temperature. Hard water, which is common in Adelaide and parts of Perth, can dull the flavour of tea and leave a thin film on the surface of black tea. Filtered water often gives a brighter, cleaner cup in those areas.
Use fresh, cold water each time rather than reboiling what has been sitting in the kettle, and keep the kettle descaled so mineral build up does not affect the taste. Measure your leaves too. A common starting point for Western style brewing is around 2 to 3 grams of leaf per 250ml of water, adjusted to taste.
If you are choosing a kettle with tea in mind, look at whether it offers preset or adjustable temperatures, how accurately it holds them, and whether a keep warm function suits your routine. Comparing glass, stainless steel and temperature control models side by side, as in Hello Kitchen's kettle range, is an easy way to see which features matter for the teas you drink most.
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