Tea is more often than not brewed in hot water with the water temperature ranging between 140 °F for delicate green teas and 212 °F for more robust, oxidized and roasted teas.
Nowadays, cold brewing tea is becoming more and more common while brewing tea with hot water still is the norm. Brewing tea with how water has some major advantages over cold or room temperature water.
SHORT ANSWER – Why Tea Is Brewed In Hot Water
Brewing tea in hot water allows for more flavor to be extracted from the tea leaves. Some compounds responsible for the taste and aroma of the tea are not soluble in water at room temperature. Some bitter compounds are only extracted noticeably when using hot or boiling water to brew the tea.
This quick run-down of the concept may give you an idea of why hot water most commonly used to brew tea. Brewing tea with hot water is not the only and not always the best way to make tea.
In this post I want to share the advantages and disadvantages that come with various temperatures. There is a place for cold brewing as well as room temperature, hot and boiling water to brew your tea.
How Hot Water Yields More Flavor
To explain the difference between cold and hot brewed tea, you need to understand the effect the temperature has on the extraction of flavors from the tea leaves themselves.
Generally, hot water is able to hold more flavor compounds than cold water can. Because of this, hot water will yield more flavor. But keep in mind that some flavors are slow or impossible to dissolve in cold water.
What Flavors Are Extracted At Low Water Temperatures?
Many compounds responsible for the taste of your tea are perfectly soluble in water at room temperature. That’s the reason why tea, even if you decide not to use hot water, will not be tasteless.
At colder temperatures, mostly sweet, vegetal flavors will be extracted. A tea made at room temperature will not be very complex in taste, but may still taste quite good.
What specifically takes longer to be extracted are tannins, caffeine and other more complex molecules. Many of the compounds responsible for bitterness, mineral taste, dry-mouth. and the dark color of tea are not extracted well with cold water.
Further, the body and umami of a tea will be less noticeable when using colder water. Brewing tea in cold water or at room temperature will, as stated, mostly extract sweet, floral and vegetal flavors.
DID YOU KNOW
A long time ago, the method of choice for consuming tea was chewing the tea leaves directly from the bushes. While the caffeine in the tea leaves gave energy, the taste of the tea leaves is not as enjoyable as the modern processed tea is.
How Does Boiling Water Extract More Flavor From Tea?
How Temperature Affects Caffeine Content In Tea
To further visualize the concept, I want to go into detail with caffeine. Caffeine is extremely soluble in boiling water and still well soluble at 176 °F (80 °C).
All compounds in tea get less and less soluble with falling water temperatures, which is also why tea gets cloudy when it cools as some compounds fall out of solution.
| Water Temperature | Caffeine Solubility |
|---|---|
| 212 °F / 100 °C | 666 mg per ml |
| 176 °F / 80 °C | 200 mg per ml |
| 77 °F / 25 °C | 16 mg per ml |
As the table shows, caffeine gets much less soluble at lower water temperatures. At room temperature, caffeine is only about 2.4% as soluble as it is in boiling water.
Speaking of caffeine in tea, do you know why tea contains caffeine at all? To find out, read this post where all reasons are explained in detail.
Why And When Brewing Tea With Hot Water Makes Sense
You now understand what temperature does to the solubility of caffeine. Applying that to all other compounds that are responsible for the flavor it becomes clear that brewing tea in hot water has its advantages.
As long as the tea does not contain too many compounds that would create an unpleasant taste when brewed with boiling water, like most green teas do, hot water is the way to go.
With delicate teas such as green teas and especially Japanese green teas, the bitterness can quickly become overwhelming if you brew the tea in hot water.
On the other hand, highly oxidized and heavily roasted teas such as black tea and many oolong teas are much less susceptible to this. That’s the reason why these teas are brewed in boiling hot water.
Why Cold Brewing Tea Is A Thing
Cold brewing is a very popular method, which is often used to make fresh and aromatic teas for hot summer days.
Instead of letting tea that was made with hot water cool, the tea is intentionally made with cold water with long steeping times. The resulting tea is quite different and, if done correctly, very aromatic.
Effects Of Cold Brewing Tea On Its Taste
Brewing tea with cold water will yield a unique flavor very different from the same tea brewed in hot water. Most commonly, the water is cooled in a refrigerator and infused for 12 to 24 hours.
At such low temperatures, bitter compounds such as tannins are nearly insoluble. The same goes for caffeine, whose concentration in the resulting infusion will be low.
Water-soluble compounds will still be extracted and the sweetness and floral, vegetal and fruity flavors will be most dominant in the resulting infusion.
Of course, some flavor compounds will remain in the tea leaves because the temperature is too low to extract them. But that is what makes cold-brewed tea a simple and enjoyable tea.
Keep in mind, that as long as the tea leaves remain in the water, it should not be allowed to heat up to room temperature. Otherwise, unwanted flavors such as bitterness may still be dissolved due to the higher temperature.
Do Longer Infusions Substitute Brewing Tea In Hot Water?
There are some advantages to long infusion times over shorter ones with higher water temperatures. Some compounds that could have a positive impact on the taste of the tea take time to extract.
Because the tea leaves are a natural barrier, some compounds are trapped inside of them. These can take a while to reach the surface of the tea leaf and be transferred to the water.
With higher water temperatures, these compounds may not be extracted from the tea leaves, which would yield a less complex taste profile. But again, higher water temperatures will yield a harsher and potentially bitter tea.
The taste of tea brewed in hot water is very different from tea brewed with water at 40 °F (4 °C) as different compounds will be dissolved in the water. I highly recommend tasting both methods side by side.
Why Is Tea Not Brewed At 80 Degrees?
So if there are advantages to cold brewing tea and brewing tea in hot water, why is tea not brewed at 80 degrees (26 °C)? Brewing tea at room temperature would be very convenient, right?
Brewing tea at 80 degrees (26°C) does not sufficiently lower the solubility of bitter compounds. With the longer infusion time, brewing tea at room temperature offers no advantage over cold brewing tea. Brewing roasted, oxidized or fermented teas at 80 degrees does not yield a full taste.
Brewing tea at room temperature will either create a tea that is too bitter or a tea that has not dissolved enough flavor compounds to be enjoyable.
Of course, some teas will brew fine at room temperature, but those would surely be better with hot water or actual cold-brewing techniques. By experimenting yourself, you can determine your preferences.
There’s a lot more to learn about tea! If you are looking for a good place to start, I highly recommend the book Tea: History, Terroirs, Varieties. You can check its current price on Amazon here.
