Why can't you make tea with cold water?

The Temperature Affects the Antioxidant Content of Tea

Tea is consumed not just for its refreshing and hydrating capabilities but also because it has been proven to be healthy. The health benefits of tea are in direct proportion to its antioxidant content.

The reason why tea undergoes hot infusion is that hot water results in a faster extraction speed and power. In other words, hot water pulls out the healthy compounds found in tea faster, but it can degrade and destroy the healthy compounds a lot faster, too. This is why when steeping your tea with hot water, the recommended times are between 1 to 10 minutes depending on the type of tea you are using.

But, then again, we can also prepare tea with cold water.

The cold water tea infusion is gentler and does not degrade the healthy compounds in tea as much as hot infusion does. That means cold water tea infusion takes more time to happen but results in a tea that contains more healthy compounds.

One study aimed to test how tea preparation would affect the quality and quantity of healthy compounds in tea.

The researchers used black tea, green tea, and oolong tea and compared three different brewing methods in their study.

  • Standard hot water infusion.
  • Cold water infusion.
  • Hybrid tea infusion.

The standard hot water infusion was at 194°F (90°C) for black tea, 167°F (75°C) for green tea, and 185°F (85°C) for Oolong tea. The amount of tea used was 12 grams, and it was placed in 33 oz (1L) of water. The teas were left to steep between 3 to 4 minutes.

The cold water infusion was at 39.2°F (4°C) and lasted for 12 hours. Between 7 and 8 grams of tea was placed in 33 oz (1L) of water.

The hybrid method added 30 grams of tea to 20 oz (600 mL) hot water at 176°F (80°C) and lasted between 3 to 5 minutes, after which 0.9 pounds (400 g) of ice was added to the tea.

Then researchers examined the catechins, gallic acid, xanthines, total phenolics, and antioxidant content.

The researchers found that cold infusion leads to a higher concentration of antioxidants compared to the classic hot infusion. The hybrid method, however, was also able to produce similar effects to the cold infusion. The initial subjugation to hot water sped up the extraction process while the rapid cooling off was able to prevent the antioxidants from degrading.

Then the researches went on to see if people would prefer one tea over the other.

When they served the different teas to 24 non-expert participants, they discovered that the participants did not enjoy the tea, which was prepared using the hybrid method. The reason for that was believed to be the altered flavor due to the stronger astringency and aroma.

Another study examined how different brewing temperatures (167°F/75°C, 185°F/85°C, and 203°F/95°C) and different brewing times (1, 2, 3, 5, 10, 20, 30, and 45 minutes) affected the catechins in Turkish green tea.

The highest concentration of catechins in the Turkish green tea was observed at a brewing time of 3 to 5 minutes at 185°F to 203°F (85°C to 95°C).

Another study found an interesting correlation between tea leaf size and antioxidant concentration in tea.

In this study, researches compared whole leaves vs. milled leaves. They tried subjecting the two different types of tea to different brewing temperatures and different brewing times. For this experiment, researchers used white and green tea.

Milled tea across the whole board ended up being more astringent and pungy compared to whole leaf tea, and to no surprise ended up having the best antioxidant activity.

But the best extraction of the healthy compounds in tea was achieved with cold water for 120 minutes, while with hot water, the best extraction was achieved at 90°C for 7 minutes.

Whole leaves performed best with the cold water infusion process.


Some Flavor Compounds Do Not Dissolve Well In Cold Water

Cold water is not able to extract as much caffeine, catechin, polyphenols, proteins, flavonoids from the tea leaves. The amount that can be extracted is very dependent on the water temperature. This is due to the solubility of most compounds increasing exponentially with the temperature.

It is a general rule that compounds are more soluble in hot or boiling water than in cold water. This is due to the fact that liquids are able to hold more molecules in solution at higher temperatures.

What this means for your tea is that some compounds are much less soluble at room temperature or below than they would be when brewing with hot water. There are both positive and negative effects to this.

For example, you’d never prepare a green tea with boiling water, right? That is because green tea has a lot of bitter compounds that have not been degraded through oxidation (to black tea) or roasting (often found with oolong tea).

Molecules like various proteins, flavonoids, polyphenols, caffeine, catechin and many other compounds are not dissolved easily in water at low temperatures.

Other molecules are still soluble quite well at low temperatures. There is always a trade-off. You will get less flavor out of the tea leaves, but that may help with the bitterness of a tea.

What you need to do when brewing tea with cold water is simply using more tea leaves. That way, more compounds in total than can be dissolved while still getting less bitter compounds and caffeine.

There’s good reasons to try cold brewing but also some important things you need to be aware of. The most important ones are listed further down in this article.

How much tea to use for cold brewed tea

Okay, now let’s do the math. If you were to use a standard of 2 teaspoons of green tea for 250 ml/8.5 oz of brew, then let’s multiply all of that by how large your pitcher is.

If you’re using a 1 liter/ 33.8 oz pitcher, then you’d assume you need 8 teaspoons of tea leaves for your cold brewed tea. This would be the most logical approach.

But, remember that tea reacts much more slowly to cold water. So you’ll have a different product if you use as much tea as you would for hot brewed tea.

I recommend using 12 teaspoons of tea leaves for 1 liter/33.8 oz, and diluting the brew with additional water if it ends up too strong for you. If it’s just fine, then great, you’ve found your ratio of leaves to water.

I short, using 3 teaspoons for every 250 ml/8.5 oz of water will guarantee a tea that will match your hot brew. Serving the tea over ice cubes means you’ll have to brew it even stronger than this.

If you’re brewing with a gallon of water, you’ll need 45 teaspoons of loose leaf tea. That’s 15 tablespoons, and easier to keep track of.

We each like our tea stronger or lighter, and I have no idea how you like yours.

Keep in mind that I take my tea quite strong and these measurements reflect that. So if you know you like lighter tea then feel free to add less tea than I mentioned here.

(If you like this article so far, you can pin it to your Pinterest board by clicking the image below. The article continues after the image.)

Roasted Oolong

Green teas are unoxidized; black teas are fully oxidized. Oolongs lie in between—partially oxidized and meticulously processed to draw out unique rounded qualities and powerful fragrances and finishes. Often that processing includes roasting, and if you’re looking for a darker iced tea with a crisp, clean bite and notes of honey, flowers, and cream, roasted oolongs are just the thing. For cold brew, I prefer the relatively lighter roasts you’ll find in roasted baozhong and roasted high mountain oolongs from Taiwan, but some heavily roasted tieguanyin makes for a buttery, floral indulgence, too. I’d recommend avoiding unroasted “green” or “jade” oolongs for cold brew, though, as they can veer toward astringent.

Eco-Cha Jin Xuan Oolong Tea, Loose-Leaf Buy on Amazon

Expert Tips

  • Ice is optional since the tea is already chilled, but add ice to keep it colder for longer.
  • Not all tea is cold brewed for the same amount of time. Green tea in general is trickier to cold brew. It can taste bitter if not made properly so always check brewing guides. Black tea, oolong tea, and herbal teas are the easiest to brew since it’s harder to mess up and should be cold brewed for 12 hours.
  • Instead using a strainer, the easiest way to cold brew tea is in a cold brew maker since you can just take out the infuser instead of straining the tea into another container.
  • Make and store your tea in glass containers. Plastic tends to stain and leave behind odors.
  • Keep cold brewed tea in constant rotation by starting a new brew 1-2 days after starting the first.
  • Cold brewed tea can be stored in the refrigerator for up to 4 days.

How to Make Hot Tea 2 Ways

How to Make Tea Using a Tea Bag

We'll start with the easiest option for how to make tea: Using a tea bag.

  1. Place a tea bag in your cup or mug.
  2. Bring fresh, cold water to a rolling boil.
  3. Once boiling, pour over the tea bag and steep according to the timing above based on your tea variety.
  4. Remove the tea bag from the cup.
  5. If desired, finish with milk, your preferred sweetener (such as sugar, honey, agave, or stevia) or a slice of citrus.

How to Make Loose-Leaf Tea

If you choose to steep loose-leaf tea, you'll need a tea infuser. These may come inside your teapot (like with this AUBCC 32-Ounce Glass Teapot with Stainless Steel Infuser; $16, amazon.com), or you can buy a single-serving tea infuser (such as these Stainless Steel Tea Infusers; $14 for two, amazon.com) to pop inside a single cup.

  1. Fill the infuser with the amount of tea specified on the package for how many servings you need.
  2. Bring fresh, cold water to a rolling boil.
  3. Once boiling, pour over the tea infuser (or lower the infuser into the pot) and steep according to the timing above based on your tea variety.
  4. Remove the tea infuser from the cup or pot.
  5. If desired, finish with milk, your preferred sweetener, or a slice of citrus.

Related: Our Best Hot Tea Recipes (Including Chai!)

There Is A Lot Less Caffeine In Tea Made With Cold Water

Caffeine is more than 41 times more soluble in boiling water and 12 times more soluble in hot water when compared to water at room temperature. Cold water will yield a tea that contains a lot less caffeine and allows for a cup of tea in the late evening. Tea with less caffeine is also less bitter.

Caffeine is a compound where the difference in solubility is extremely high between cold, hot or boiling water. Depending on taste and time of day, you should keep this in mind.

At room temperature (77 °F, 25 °C), a cup water (about 237 ml) will hold up to 3.79 grams of caffeine while the same cup can hold 47.32 grams at 176 °F (80 °C) and 157.57 grams at 212 °F (100 °C).

This does not mean that these amounts of caffeine will be dissolved when making tea! But these numbers can get you an idea of how the solubility increases rapidly when raising the temperature.

Consider that hot water can dissolve more than 12 times the caffeine than water at room temperature can. And caffeine is more than 41 times more soluble in boiling water than room temperature water.

If you want a strong caffeinated cup of tea, you should not brew your tea with cold water. But if it’s late in the evening, you could try a cold brew and increase the quality of your sleep.

But what about those instant hot faucets found on water coolers?

The instant hot faucets are a great way to reduce the boiling time of your water. Since the water is stored in special polycarbonate jugs, it will not pick up any metallic flavors or minerals. The instant hot also immediately heats the water instead of storing hot water so the oxygen levels will be high as well. There really is no downside to using this water to fill your kettle.

6. What Ratio of Tea to Water Should I Use?

at least6 tablespoons of tea3 quarts of water8-9 tablespoons3 quartsregular, single-serve tea bagssingle-serve bags3/4 teaspoon“family size”Luzianne black tea bags1 tablespoon24 single-serve tea bags32-36 tea bagsfamily size bags68

How cold brewed tea tastes different than hot tea

Cold brewed tea is always going to be different than hot brewed tea.

This is because in hot water, the tannins in tea are extracted in larger quantity, and very fast. This is true for all ‘true teas’, and herbal teas do not have this problem.

However all tea, whether herbal or not, taste very different when brewed hot and left to cool. They taste a bit hollow, or flat, like there’s not much aroma left in them.

In truth, aroma and flavor do evaporate from your tea in time. Storing it properly will ensure that you’re getting the longest possible shelf life from your tea.

And it also means that hot tea will evaporate aroma in a couple of hours.

Cold brewed tea is going to taste more delicate and subtle than hot brewed tea. The bitterness will be all but gone, even with green tea which is famous for muck ups.

Floral infused teas will taste wonderful, and fruit infused teas are going to be extra fresh. For example adding lemon zest to hot tea will taste like warm lemon, which can be nice. But ice-cold lemon ? How cool is that ?

You might need to adjust your taste buds to cold brewed tea, since it won’t be the same as the hot version. And if you brew mint tea like this, go easy with it since it can cause a sore throat.

There’s also some caffeine in tea brewed with cold water. Caffeine does exist in your tea, but without hot water to release it faster, it’s going to have a harder time steeping.

It will steep out, since for cold brew coffee you need a minimum of 8 hours for it to fully release. And coffee has pretty much double the amount of caffeine than tea, so it will need less than 8 hours to release fully.

Ingredient Notes

Loose tea or tea sachets
Any and all kinds of tea
  • Loose tea or tea sachetsAny and all kinds of tea can be cold brewed.
  • WaterUse filtered water for a better tasting cold brewed tea.

My Glass Container Pick Photo Credit: williams-sonoma.com In the summer, I fill these Weck jars with all different kinds of iced tea. SEE PRICE ON WILLIAMS SONOMA

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