Why You Must Pay Attention to Water Temperature When Making Tea. Really.

Having looked at how (and if) water itself impacts the flavor of your tea (see post), what about its temperature? Does that matter?

Yep, it matters. 

A lot. Even back in the year 780 when Lu Yu wrote the still-classic The Classic of Tea.

Tea master Lu Yu specified his method in great detail.

Water (ideally from one of the rivers that he rated as among the best sources) was put into a cauldron on a stove and heated.

• At first boil—when bubbles the size of small fish eyes formed and a faint sound was generated—a pinch of salt was added to the water; some of this water was removed and retained in another container. (160–180°F)
• At second boil—when continuous strings of bubbles, like a strand of pearls, formed on the edges—the water was swirled with bamboo tongs and tea poured into the water.
• At third boil—when the water resembled swelling waves or crashing breakers, or what we’d call a full or a rolling boil—the retained water was added back in so that the brew maintained its bubbles but didn’t over boil. (Water boils at 212°F.)

The tea that Lu Yu added to the boiling water was actually a powder. He would have dried a cake of tea—unoxidized tea leaves that had been formed into a compressed cake—over a stove. Once it cooled, it was ground and sifted so that only the finest powder remained.

For today’s teas, water temperature is still vitally important so that you get optimal flavor without drawing out too much of the bitter tannins and caffeine, which are extracted with hot water. However, caffeine goes hand in hand with flavor, so you want that caffeine.

Polyphenols, which also contribute both flavor and health benefits, are extracted quickly, so you want to drink your first infusion and not throw it out in the mistaken belief that you can remove caffeine from your tea. Every infusion will draw out more caffeine, especially as full leaves unfurl.

Conversely, you don’t want your water temperature too low because then your tea will be weak and flavorless, or lack the proper astringency.

To cool water, you can simply let boiled water stand for a while or you can transfer it into another (unheated) container so that it cools more quickly. Having a thermometer to check the temperature is a good idea.

If you need to cool water only a bit, you can do a “high pour,” holding the water kettle high above your teapot or teacup so that the water cools as you pour it.

Electric kettles that can be programmed for specific temperatures are a hassle-free option.

What you drink in your teacup ultimately is a combination of the leaves themselves, water, ratio of leaf to water, brewing temperature, and brewing time—all of which can (and should) be tweaked to your personal preference. Yet, there are overall guidelines.

Black teas

Use temperatures from nearly boiling (194°F) to boiling (212°F).

As seen in the English Westminster tea pictured here, black teas are heavily oxidized and are best brewed with boiling water.

A few, however, such as Japanese black tea, will do better with water that has been boiled and then cooled for a few moments, so that it’s at 194°.

Oolong teas

Oolongs range in oxidation from those closer to green teas to those closer to black, so their brewing temperatures can vary from 176°F to boiling. However, these often tightly rolled teas generally require boiling water.

Some, like the Milky Jade shown here, are versatile and will yield different flavors depending on which temperature you choose (for this tea, either 194°F or boiling).Green teas

Less oxidized and more delicate, green teas require lower brewing temperatures, although they have the largest temperature range: 140°F up to 194°F.

The Japan sencha shown above requires 194°F water, but many other greens must be brewed at a lower temperature so that they are not ruined. Gyokuro—a specialty of Japan and a premium tea known for its richness and umami—must be brewed at 140°F.

White teas

Delicate in flavor, most white teas are brewed at 158°F although some require 176°F.

Boiling water will definitely ruin these unoxidized teas, such as the China Silver Needle shown here.

Tisanes

Tisanes, or “teas” that don’t contain tea leaves, include fruit blends, herbals, honey bush, and rooibos. These, with a few exceptions, are brewed with boiling water.

Upshot?

Pay attention! Read and heed the directions provided with your tea, and in the absence of any instructions, use these guidelines.

Whether fish eyes or raging water, that temperature means the difference between a blah cup of tea and the perfect cup of tea!

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Source: High Tea, by L. E. Barnes, Norton Museum of Art, W. Palm Beach, FL, 2014.

Teas shown here are available at TeaHaus; brewing chart courtesy of TeaHaus.