Why Is Tea Brewed in Hot Water? (Plus the Pros and Cons of Cold-Brew)

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Tea is one of the oldest and most beloved drinks in the world. It’s roughly estimated that tea has been in this world for approximately 5,000 years.

In these past thousands of years, the love for tea has expanded from being an interest in a single leaf to having hundreds of different flavors and types of tea, with tea enthusiasts all around the world. Throughout history, tea has had an important impact on trade and culture, and it has been cemented as a historic drink.

With that being said, there are plenty of people who are interested in tea, its history, and how it came to be how it is today. People might be interested in what flavors are the most popular in certain areas of the world, or how certain tea-related traditions have come to be what they are.

One of the oldest questions in the book, especially from newer tea enthusiasts, is why tea is almost always brewed in hot water. After all, if the process of brewing tea is simply soaking the tea leaves in water, why does the water have to be hot, and is it even possible to make a cold-brew tea?

The short answer to this is that, as with other aspects of life, the hot water affects the tea leaves differently than room temperature or cold water would. You can still make a cold-brew tea, but it is going to have different properties to it than your standard tea would.

For the most part, brewing tea with hot water is done as the hot water helps to draw more flavor out of the leaf, creating a better-tasting tea, which is what most tea enthusiasts are after.

The Science Behind Tea Brewing

Hot water is optimal compared to lukewarm or cold water in a number of situations. Hot water can change the properties of plenty of different objects, as it is the heat that works on the object in question and the water just happens to be a medium for that heat.

Take noodles as an example. You can’t really cook noodles in lukewarm water effectively, and you certainly can’t make noodles in cold water, but with hot water, you can alter the structure of the noodles and turn them into the food that everyone knows and appreciates.

The concept of this applies to appliances, such as dishwashers and washing machines, to take the stains out of clothing or dishes. It also applies to other areas in cooking, such as brewing tea.

The heat from the water has an effect on the leaf itself, which is what helps to make it so popular in the world of brewing teas. The most common temperatures for brewing teas range from 140 degrees Fahrenheit for the more delicate green teas and up to boiling temperatures for the more robust teas out there.

Water of this temperature is able to “hold” more of the molecules and compounds that create the flavor of the tea that you are making.

Tea leaves have numerous compounds in them, and by soaking the tea leaves in water of any temperature, you help to draw those compounds out of the leaf and into the water itself. It’s just a matter of temperature that affects which compounds, and how many of them, will be drawn out.

Because hot water is able to “hold” more of those molecules, you will get a stronger taste from the tea. Keep in mind though, that with certain teas, too high of a water temperature will mean that the flavor molecules will not be absorbed as well and you will be left with a different or dulled taste.

If you are making a specific type of tea, it is always best to follow the temperature guidelines set in place.

Brewing teas with hot water, however, is not always the best thing for you to do. Some teas do not do too well in hot water, as some of the compounds that are extracted are not the flavorful ones that you are after, but are compounds that have a more unpleasant taste to them.

Using hot water to brew your tea absolutely has its advantages, especially with robust leaves that have many flavors in them that can be extracted, but naturally, there are also times when it doesn’t make sense to use hot water.

Sometimes, it is better to use (relatively) cooler waters. This means, instead of opting for a water temperature of near-boiling, you would opt for a temperature between 140 and 150 degrees Fahrenheit. This isn’t cold, by any means, but comparatively, it’s rather lukewarm.

This kind of mellow temperature for teas is best for when you are working with delicate tea leaves that will only end up being bitter when exposed to higher temperatures. This mainly includes green teas.

Where Cold Water Comes in

Cold water has become more and more popular in recent years for brewing teas, as more people discover that it will draw out different flavors from the tea leaves that you are working with. The same tea leaf that you would use in hot water may have a wildly different taste when exposed to cold water.

Because the process of making a cold-brew tea is a bit different than just letting the tea brew in a boiling kettle, you should expect to give up to 24 hours for the tea to infuse with the water to get the most out of its flavor.

The difference with cold-brew teas is that, in this colder water, many of the more bitter compounds such as tannin and caffeine are not soluble into the water, meaning that they will not be absorbed into the flavor of the tea, though this also means that you will have a lower caffeine content in most cold-brew teas that you make at home (since commercial manufacturers have ways of artificially adding caffeine).

Most of the undertones that come from cold-brew teas tend to be far more floral, fruity, and vegetal. Under these flavors, you will likely have sweeter undertones to it than you would with most standard teas that you make.

For these reasons, cold-brew tea is incredibly popular during the summer months of the year, where everyone can enjoy a nice, sweet, and fruity glass of cool tea without having to heat up a room while trying to boil water.

Brewing cold tea is something that takes a slightly higher amount of effort, space, and most notably, time. Brewing warm tea takes a matter of some minutes, whereas making a cold brew takes up to a full 24 hours to complete.

During that time, the cold water you are using should not be allowed to reach room temperature, or the bitter compounds will be able to come into the tea once again. Depending on how much space you have, this may present a problem.

You cannot brew tea at room temperature. To be more specific, you can, but it will be the worst of both worlds. You won’t get the full, robust flavors that come out of teas that are brewed with water that is warm or boiling, and you won’t get the floral and fruity flavors that come out of the colder water.

Instead, you will get just about all of the bitter compounds and none of what you actually want. So, you can brew a tea at room temperature, but it would be a tea that nobody really wants.

How Do You Know What Temperatures to Brew at?

Naturally, the best way to figure out what temperature you should brew your tea at is to experiment for yourself. Tea is relatively inexpensive and water is as inexpensive as drinks can get, especially from the tap.

If a tea doesn’t turn out well enough to drink, even with some added flavors, it will not cost you too much to toss out. However, some people may not be too comfortable experimenting with their tea without a base to start on.

Typically, green teas will benefit from the low end of warm water, while highly oxidized teas benefit from the full boiling temperatures of water, if you are opting to brew your teas with hot water.

Many tea enthusiasts have guides as to what the best tea brewing temperatures are, making it easy for people who are new to tea to find out what they should be working with. These guides will even get as specific as how large the bubbles in the water should be to indicate the best brewing temperatures.

For common tea types, green tea is brewed between 150 and 180 degrees Fahrenheit, with white tea being in the middle of that at 160 degrees. Black tea and Oolong tea share similar temperatures of 180 to 212 and 190 to 200, respectively, meaning that you can easily brew them in the same range.

Pu-erh tea and herbal teas can be brewed at a full boil without risk of being too hot and getting unwanted bitter compounds in them. Certain types of tea within these categories may have different brewing temperatures, but these can act as a reference to base your experiments off of.

Cold-brew teas are almost always brewed in the fridge, so you don’t have to think about the temperature of that nearly as much. Most fridges in the United States will fall within the temperature range of 36 to 40 degrees Fahrenheit, and this is preferably for most cold brews, regardless of the type of tea you are working with.

What Are the Benefits and Cons of Hot or Cold Water?

With this knowledge, you might begin to wonder whether you should opt to brew your tea with hot water or if you should try using cold water.

The true answer to this is that it is completely up to you and optional, but there are some undeniable advantages and disadvantages to choosing hot water or cold water over the other.

The benefits of using hot water to brew your tea include taking far less time to really infuse and get all of the flavors you want into the water. This means that you don’t have to wait as long for your tea if you are thirsty in that instant.

Brewing tea with hot water is far more common, so you will find many more enthusiasts and tea types to work with and research, if you are interested in trying new things. If you want to share your love for tea with others, this is one of the best ways to get the job done.

There is also a much, much broader range of flavors that you can get out of brewing your tea with hot water, compared to using cold water, which can be more fun and enjoyable if you like trying new things.

The disadvantages of using hot water include the fact that different tea types do best with different temperatures. Unless you are making tea with water at a full boil, this means you are going to have to fuss and fiddle with thermometers and your stovetop to get exactly the right temperature of water.

This is even more important for exotic and rare teas that you will come across, especially when there are specific undertones to look for. This also means you can’t use one blanket temperature for everything, unless you enjoy bitter green teas or undeveloped black teas.

Other disadvantages of using hot water include that if you want something fruity, cool, and fun, you’re not going to have much luck. Most hot-brewed teas have a robust taste and they are often far more subtly flavored in terms of sweet or fruity undertones.

If it is hot outside and you want some tea, tea that has been brewed with just-boiling water is probably not going to be the best either.

On the other hand, the advantages for cold-brewed tea include the fact that you don’t have to mess around with a specific temperature. Instead, you can just stick the tea into the fridge, let it infuse overnight and through the next day, and you will have your tea ready.

If you enjoy sweet, fruity, and floral flavors, then cold-brew tea is going to be right up your alley as most cold-brewed tea will have the same basic flavor profile, with different teas having different undertones, but nothing standing out as starkly as most of the boil-brewed teas. Cold-brewed teas are best on a hot summer day to cool down.

The disadvantages of cold-brew tea is that you have to wait for it. At a sheer minimum, you have to wait 12 hours for an infusion to finish, and if you want the most flavor possible, then you have to wait a full 24 hours.

Depending on the amount of tea you made, this can take up a lot of space in your fridge, which can be annoying to deal with.

You don’t get to experiment as much with flavors and trying new things either, which may not be as fun for some people. Finally, cold-brewed tea tends to have noticeably less caffeine in it than other teas, so if you are looking toward your tea for a caffeine boost in the day, you won’t have much luck if it’s a cold brew.

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