Iced Green Tea Health Benefits

by Marybeth
(Green Bay, WI, USA)

I read somewhere that a good idea is to steep 3 green tea bags in 24 oz. of water for 10 min., then drink it throughout the day. I usually wait for it to cool, then add it to a glass of ice. Am I still getting the antioxidant benefits? Or should I drink the steeped tea within one hour?


Marybeth, the ratio of one tea bag (about 3 gram) to 8 ounce of water looks about right. So the question is about steeping time and whether tea bags do contain enough antioxidants.

How long can you store brewed green tea without losing the antioxidants benefits?

I believe, the answer is a few hours, up to half a day, but it really depends.

If you ice the tea, fridge it in an airtight container it may keep longer, the most important thing is to learn to read the signs of the quality of tea.

This question has been asked many times before, so it is best you scan through the following article:

Cold Tea Vs Hot Tea Health Benefits
- How Long Can You Keep or Steep

As for the second question - I don't believe tea bags contain much antioxidants (so yes, you can store them for a long time, because it hasn't got much antioxidants to start with!).

There are two reasons.

First, they are made of very low grade tea leaves.

Second, the leaves have been chopped into pieces - any antioxidants would have oxidized.

I hope this helps.


PS: By the way, today the 2009 harvest Biluochun green tea has just gone live!

Biluochun Tea (Piluochun)

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Brew Green Tea - Better To Leave Overnight?

by Ami

I have just started drinking green tea after reading about its health benefits but wasn't sure of how to make it. Is it better to keep the leaves overnight in water and then drink it in the morning? Could you also let me know of the amount of water and green tea leaves to use each time?


Ami, there have been a lot of readers writing to me asking about leaving green tea overnight. Most of them are based in America, where people enjoy drinking iced green tea in the summer. The idea is to steep the tea, then leave to cool in the fridge before drinking.

In Asia, we tend to drink green tea hot, and not leave overnight. The scientific reason is because green tea antioxidants are extremely reactive, and therefore vulnerable to environmental degradation. You can see that when you see the tea liquor turns brown after a while - it is called oxidation - just like apples turning brown. The effect is more marked on the high grade which contains high level of antioxidants.

So to conclude, best to drink green tea fresh, especially when you are drinking a high grade.

Start with 2 to 5 grams per 250 millimetres (8 ounce). Start with less first, then gradually increase to your taste. It is harder to get it wrong with less leaves. Good quality tea leaves can steep more than 3 times.

Further information about brewing green tea can found at

How To Make Green Tea - Brewing Secrets FAQ Guide

I hope this helps.


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Jul 13, 2009
Steep Overnight
by: Erik

I have been steeping my tea overnight for the past year or so. I pour the boiling water over the leaves in thermos jars, and then cover it up, in the morning it is still warm when I drink it for breakfast, doing it this way I highly doubt that the anti-oxidants would disappear out in nowhere.

Also its a great drink to drink after a night of drinking alcohol, because it cleans out your system.

I also use organic lemongrass in every tea batch I make, Lemongrass is a natural detoxifier, and it also sweetens up the tea naturally.


Aug 02, 2009
Drinking Fresh Tea
by: Anonymous

Unfortunately drinking freshly brewed tea (hot) increases the risk of esophageal cancer significantly---this is thought to be the cause of the high rate of this cancer in Southeast Asia (China etc).

I don't agree--the antioxidant quality of overnight seeped tea does not change that much and is safer to drink (although it can be bitter).

Aug 02, 2009
by: Julian

Thanks for the really helpful comments. Really appreciate it.

Drinking hot beverage (not just tea!) does cause cancer. So the trick is to drink after the beverage has cooled down. To quote this Iranian study about hot tea and cancer:

Scientists set out to investigate why the Golestan province in northern Iran has one of the world's highest rates of esophageal squamous cell carcinoma, the most common kind of tumors of the esophagus. Locals don't use much tobacco or alcohol, the main cause for such cancers in Europe and the U.S. They do drink tea at temperatures that often exceed 70 degrees Celsius (158 degrees Fahrenheit), the researchers said.

Still, better to wait until it cools down a bit before taking the first sip. Previous studies from the U.K. have reported an average temperature preference of 56 to 60 degrees among healthy people, the researchers said.

Hot Tea and Cancer

Leaving antioxidant-rich tea too long may allow them to oxidize, thus losing potency. A 2001 study conducted by The Chinese University of Hong Kong discovered that you can keep your tea at ambient up to 7 hours, and still enjoy its antioxidant benefits.

Cold Tea Vs Hot Tea Health Benefits - How Long Can You Keep or Steep?

I agree Erik's idea of storing tea in thermos is a good one.

Feb 06, 2011
Don't listen to people here, they are talking rubbish
by: Peter

Green tea doesnt increases risk of esophageal cancer, it inhibits that.

Also don't put your tea to thermos jar during night. Thermoss jars are often made from some metals(iron/steel), which boosts tea oxidation and changes taste significantly(to worse).

Especially when you drink high quality tea, never use metal jars.

Aug 31, 2011
Green tea overnight
by: Anonymous

i suffered from irritable bowel syndrome for many years in my early 20's and started using green tea, i admit i was ignorant about how to brew it, but i would leave the leaves overnight in a glass jug,(covered) and would drink it very-very strong.

In two weeks my bowels became extreemly constant and have never had any problems since, and am 100% healthy, 36 and still drink it everyday.

And.... I lost an incredible amount of weight,and became very lean.

Mar 24, 2012
Overnight second brew
by: tealover

I do this with oolong tea. I steep one cup to drink hot and then add more water and let it sit overnight for a second 8 oz. cup.

Mar 25, 2012
FRESHLY STEEPED -- ICED OUT -- GREEN TEA will solve all your problems.
by: Phillip Mc Hunt

Brew your green tea and then throw an ice cube into the cup to cool it off before drinking.

This way you're preserving the antioxidant levels by drinking the tea fresh, while also protecting yourself from the harsh effects of drinking beverages at high temperatures.


Aug 16, 2014
Overnight brewing
by: Baker Bob

For 5 months, before I go to bed I have brewed 5 tea bags in a quart size mason jar. It seals itself as it becomes room temp and is ready to drink when I wake up. This makes me feel good & energized! The tea along with a diet containing NO ADDED SWEETENERS I have lost 50 lbs.

Jul 15, 2016
Powdered green tea
by: Anonymous

I forget the powdered green tea in the car for 2 hours and the temperature was 108 degrees. Does it go bad?

Aug 20, 2016
2 hours in the car
by: Julian

No 2 hours in the heat won't kill it, don't worry.

Nov 16, 2016
Green tea bag left in hot water overnight
by: Vivian

I also brew my green tea in a thermos flask late in the evening and drink a cup of it before bed and d remaining cup after excercise in the morning( I leave the tea bag in boiled water over night). I just wanna know if that's right way to get all the health benefits of green tea.

Sep 25, 2017
I steep overnight too
by: Erik number 2

We'll talk about odd, the original Erik posted on my birthday in 2009 and it wasn't me.

I do a similar method sans lemongrass. I brew 2 liters of tea in a giant Chinese thermos and our family drinks it throughout the following day, however as someone mentioned tea sitting in metal, the reason I selected this particular thermos is a Glass lined one and uses a natural cork stopper. The tea never gets bitter doing it this way so I assume having it in the non reactive glass preserves it, always makes a very smooth tea. I typically make it around 1AM and the tea is still piping hot the following evening.

Jul 30, 2023
Safe way to brew green tea according to a dedicated tea drinker NEW
by: Rhonda

unfortunately, myriad brands of green teas have been found to contain herbicides/pesticides as well as high levels of fluoride, even ones that claim to be organic. In addition, chemicals can leach out of the teabag itself.

Here's a way to brew tea that hopefully, does away with this toxic soup of chemicals. Heat filtered water to boiling then let it cool for 2 mins. Or heat in a microwave for 1 minute 50 seconds. Swish teabag for 30 seconds, remove it and throw that water away. Then, brew the tea in fresh water that's been heated but not to boiling. Try brewing 10 minutes and if that's too strong, decrease the brewing time.

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Tea Antioxidants in Thermos - How Long Do They Keep?

by Greg

Does tea loose its antioxidants and other benefits if left out for say 8 or 10 hours?

I make tea in the morning and keep it in a thermos.

I'll still drink cups of it in the evening I wondered if it is still high in benefits even after that long.

I read somewhere that Gunpowder tea has the lowest caffeine content. Is there a green tea that has more caffeine than the rest?

Sorry seems like a weird question but even a genius ask questions. Thanks.


Greg, tea antioxidants do not tend to keep long. If you brew a high quality tea and keep it in ambient for a few hours, you will notice that the tea liquor turns brown.

This "browning" effects is oxidation.

I suspect when you store you hot tea in thermos, this oxidation effects is somewhat mitigated.

To check if your green tea antioxidants is still intact, pour your tea into a glass and check its colour and taste.

But first, you should test your tea by leaving it in ambient for a few hours.

If you are drinking a quality tea which is high in benefits, you will notice the difference that browning makes to the quality.

Green Tea Caffeine

It may be true that gunpowder green tea contains less caffeine, as they are less likely to be made of tender tea buds, which often contain higher levels of caffeine.

Tea caffeine levels does not correlate with quality. The highest quality green tea often has the highest caffeine level, but its caffeine is being more than offset by the presence of another compound: theanine.

The result is that high quality green tea is more soothing to drink that other so called low caffeine variety.

It may sound radical, but it is true. Check out the story here:

Green Tea Caffeine

Further links along the way will lead you to another article explaining why moderate levels of caffeine is highly beneficial to health.

In fact, tea antioxidants EGCG and caffeine are highly synergistic - they function much more effectively together than separately.

Hope my answer helps.

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May 20, 2008
The fresher the better
by: Kitty Wang

It is more advisable to drink the tea up shortly after it is brewed as the maximum nutrition would not sustain long.

May 22, 2008
Drink It Hot
by: Julian

Kitty, thank you for the comment. Drinking tea hot is the best option. Especially for very high quality tea.

Compounds like theanine, EGCG and chlorophyll are so vulnerable, leave them exposed to air and they will be gone - just like that.

Leave me wonder what manufacturers do to bottled green tea to preserve what little EGCG they might contain...

Oct 10, 2008
Lasting beneficial qualities of tea
by: steven

Your answer regarding antioxidants in tea seems incorrect. Many company's are extracting the beneficial qualities of tea and selling them in a highly concentrated version which can be added to hot water.

If the anti-oxidants in tea disappear within 6 hours these products would not have any validity.

What is the basis of your information? Just because te tea changes color doesn't necessarily man it loses its potency? Are there any scientific studies on the matter?

Oct 10, 2008
How Long Do Tea Antioxidants Keep?
by: Julian


You are right to be concerned. I will take the cpportunity to explain myself a bit more.

It is true that tea antioxidants are extremely vulnerable to environmental degradation, for the same reason that these active compounds are so powerful when acting against free radicals in our body.

Processed products such as instant green tea mix or bottled green tea often claim to contain high concentration of catechins/EGCG, but very often when you read into the label (yes, please do it next time!), you'll usually find either some vague wordings or very low level of antioxidants guaranteed.

This doesn't mean that these products won't improve in the future, all it means is that at present, and as far as I am aware, they do not offer the same level of antioxidants as a cup of hot green tea brewed from high quality tea buds (which has been cold stored in sealed pack from the day they are plucked and roasted). Neither are they cost effective.

For further information about scientific studies, please visit

Green Tea Beverage - Best of 7 Types Reviewed

I hope this helps.

Dec 31, 2009
To Cool Or Not To Cool
by: Cindy

Question: would it be beneficial to store tea bags in the refrigerator?

Jan 01, 2010
Tea Bag
by: Julian

When exposed to ambient, it takes only 3 months for tea leaves to acquire enough moisture to oxidize and degrade very rapidly.

How long has the teabag been sitting on the shelf? Personally I believe teabag is only good for black tea, and is of no use for green tea.

If you are talking about green teabag, it probably is not worth the bother because any antioxidants that were there probably have already been lost.


Nov 30, 2010
"lose" not "loose"
by: Anonymous

lose not loose

Feb 24, 2012
Degradation? - Not so fast
by: Leandro Ribeiro

Studies have shown that green tea catechins (GTCs) in solution do not degrade as quickly as these series of articles may led you to believe.

Zhu et al (1997 and 2001) showed GTC levels dropped no more than 20% by 18h, as long as the solution is slightly acidic (pH=6), and less than 5% if pH is 5 or less.
1997 study:
2001 study:

Nishiyama et al showed that GTCs were stable for up to 24h with brasilian green tea, stored both at room temperature and in the freezer, inside glass, opened containers.
2010 study:

Su et al report similar results, also with theaflavins.
2002 study:

These studies support the idea that one can brew green tea and drink it throughout the day with little to no loss in antioxidant properties, as long as we don't prepare an alkaline solution. Green tea already is slightly acidic, but to be sure just add a few drops of lemon juice and you're in pH=5 territory in no time.

Jun 02, 2012
Needs to respond to Leandro Ribeiro's comment
by: Anonymous

It is very disppointing tht Greg has not responded to the information provided by Leandro Ribeiro. The articles Leandro linked to seem to disprove the main claims of Greg's article.

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Does Time After Brewing Cause Tea To Lose Its Efficacy?

by Chris
(Greenfield, WI, USA)

I was diagnosed with breast cancer 2 years ago. I drink green tea daily. I recently read a short article that stated green tea loses its effectiveness as far as ECGC and polyphenols are concerned shortly after brewing (he stated 2 hours).

Is this true? I usually brew several cups and store in "fridge" to drink throughout the day. Am I losing the benefits?


Chris, I am sorry to hear about your breast cancer diagnosis. I hope you get well soon.

Brewed green tea does lose its antioxidant potential over time, but how quickly this takes place is a subject of contention, and is likely to vary from tea to tea.

This is a question that I have answered many times before, so I will direct you to some links below.

The bottom line is to judge the quality of the tea by the color (degree of browning) and taste (freshness versus staleness). From personal experience, half a day or so at room temperature is okay. The best thing to do, of course, is to drink your tea hot - a Chinese grandmother advice. But there is a degree of tolerance.

How To Store Iced Green Tea

Brew Green Tea - Better To Leave Overnight?

Tea Antioxidants in Thermos - How Long Do They Keep?

On a related note, there is an inspiring story about Essiac tea and breast cancer that you may find useful:

Essiac and Breast Cancer - A Testimony

I hope this helps.


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Mar 28, 2010
Re Tea and Breast Cancer
by: Anonymous

W.R.T Essaic tea, it may be helpful and think those concerned should investigate it. However, keep in mind a recent Chinese study showed that a diet high in green tea and mushrooms appears to reduce the re-occurrence of Breast Cancer by 90%.

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How To Store Iced Green Tea

by Tina

I have read that oxidization lessens the benefits of green tea. Is it ok to boil and brew tea as done for hot tea and then chill it in fridge to drink all day?

Also, is it REALLY wrong to toss tea bags into boiling water? i find this makes it extra strong and i really like the taste. Does this decrease heath benefits?


Tina, thank you for asking these superb questions.

It is fine to brew and chill the green tea as you suggested. To be sure you are indeed minimising the oxidation, this is what I suggest:

- Try brewing your green tea in a glass. In this way, you can detect any oxidation through the browning effects.

- Now chill your tea as you suggested. If the tea hasn't browned or deteriorate in taste, then it is fine!

As for teabags, the reason experts recommend brewing at low temperature is because they turn bitter at high temperature.

There is nothing wrong with brewing your tea at high temperature.

But usually you will find that only high quality teas can withstand high temperature brewing without turning tannic.

If you like to drink your tea tannic, there is nothing wrong with that too.

However, I will recommend that you drink more of loose tea than teabags.

Here is why:

Loose Green Tea

Also, the higher quality green tea is more sweet and delicate rather than tannic.

Best Green Tea

I hope this helps. Please let me know if there is anything I can help.

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Jan 19, 2011
Iced green tea
by: Vic

If I brew green tea using tea bags, what color should it be when I pour it into a container to chill in the fridge?

Does chilling green tea reduce the health benefits?

Does adding a little sugar to brewed iced green tea reduce the health benefit?

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Steep Green Tea For Long Time - Safe To Drink?

by Suzy

I would like to know if I make a few brews of green tea, and then leave the third brew to steep at room temperature for most of the day - is it still safe to drink?

Sometimes the leaves stay in the water as I forget to take them out - so they soak all day - is this ok?


Suzy, leaving green tea for a few hours is fine. You may observe some browning, as the antioxidants oxidise and contain few health benefits. But up to half a day at room temperature is okay. The biggest worry is bacteria, as they thrive in the tea solution. But they take a few days to emerge. I regularly leave my leftover tea for half a day, and still find them okay to drink later. It is fine. Not ideal, but safe.

I hope this helps. My apology for my late reply.


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Cold Brew Tea for Maximum Antioxidants?

by Ann

Hi, my younger sister (44) has just been diagnosed with breast cancer. I drink green tea already, but only can drink it cold.

Does that defeat the whole purpose of health benefits (which I really need as I am high risk)?

Can you tell me best way what's the best way to prepare it cold to preserve them?

Also, confused about how to buy it so that antioxidants are preserved. I guess Lipton's won't cut it but can't afford $$$ on wasted money if not necessary.

Can you help?


Hey Ann, there is no evidence that brewing tea cold will help preserve the antioxidants. The amount of antioxidants depend on a few factors:

- leaf age - normally young tea buds contain more antioxidants

- storage - need to be air-sealed and kept at low temperature

- brewing - drink while it is fresh - don't leave for more than 7 hours.

Cold Tea Vs Hot Tea Health Benefits

Brewing temperature needs to be tailored to the type of tea. Generally speaking, Chinese green teas are better at withstanding high temperature compared to Japanese green tea.

If the water is too hot, the tea becomes bitter - which is not very nice.

This has to be with the method the tea has been made (steaming, roasting, ovening etc) and how small the leaves are. I don't think it has any direct relationship with antioxidants.

For maximum value of money, and for a soothing cup of fresh green tea with lots of antioxidants, I highly recommend this Maofeng tea. It has obtained very good feedback this year:

Huangshan Maofeng Everyday Organic

The teas have been packed into air-tight bags and kept in freezer for maximum freshness.

Finally, for breast cancer, as far as I am aware, green tea and essiac tea would help:

Green Tea and Breast Cancer - EGCG Show Anti-Cancer Promise

Essiac and Breast Cancer - A Testimony

I hope this helps.


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Oct 20, 2009
Favorite Green Tea
by: Annie

Personally I prefer Prince Of Peace, I bought a big box of jasmine green tea from a health food store for $5 or less, I enjoy Jasmine more than plain green tea it has a different flavor and a pleasant uplifting smell. Also for taste I enjoy Gevalia Ancient Cherry (but its more expensive.) And we get jars of loose tea from this local store called Henry's but thats on the pricey side too.

Prince Of Peace seemed to be high quality for boxed bagged teabags, and the plain green tea is available in an organic version.

I have an iced tea maker at home, and a lot of glass jar pitchers, I can drink half a gallon or more iced tea in a day.

May 02, 2010
Cold Brew
by: Joe

I don't know if I'm getting all the health benefits but i do overnight in the fridge cold brewing with green tea bags but instead of water i use ginger ale. I love it.

Sep 21, 2019
Some people on here are ridiculous
by: Anonymous

I know this is a old post. But hot tea doesn't cause cancer of the throat, larynx, jaw, mouth,ect unless it's not real tea. Also, don't mix tea with any kind of soda if you want antioxidants. I'm pretty sure most people on this site knows when to take advice with a grain of salt. Just in case you don't...this is for you!

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