Why does my green tea turn brown after a few hours?

[Rabrrrrrr]

I often make a pot of green tea and put it in a thermos that I use only for green teas.

I've noticed that after a few hours, the tea that went into the Thermos a nice green color turns brownish. The taste doesn't change, but the color does. Is this a normal function of green tea, that it will slowly turn brown? Or is it being stained somehow by the thermos? Or maybe being starved of oxygen? Or some other process?

Do you know the answer to this question?

And when I say green tea, I'm talking Japanese green tea, which is pretty fucking green, and some pretty high quality green tea at that.

[KitchenWitch]

1. Only a guess here, but it might be oxidation

Kind of like why an apple turns brown after one cuts it. If you find the color unpleasant, you may want to add some citrus to it and see if that helps.

[Rabrrrrrr]

3. Can I just yell it into submission? That would be funnier.

But I think you could be correct -

[KitchenWitch]

6. It would be kind of like yelling at a wall

but Hey, I won't deny you that pleasure if that is what works for you!

:hi:

[Rabrrrrrr]

8. I'll throw a pair of knickers at it, as well, and stomp my feet

in a petulant frenzy.

[KitchenWitch]

16. Sounds good to me!

:hi:

[Spider Jerusalem]

2. Not lack of oxygen, but oxidation

There's going to be a certain amount of air, and thus oxygen' inside the Thermos bottle when you seal it; the oxygen reacts with the tea and causes the colour change you notice.

[matcom]

4. sorry. my fault.

:hurts:

[Placebo]

5. I left a half-drank cup of green tea on a shelf in my bedroom...

for like 2 months.

And by the end of it's sad pathetic life it was a dark syrup-like substance that I'm pretty sure became an entity and life force.

Oh yeah, and it was also covered in black stuff. Don't really know what that was.

I guess this kind of takes your slight brownage to the extreme.

...

I'm just sayin'.

[Rabrrrrrr]

7. Geez, always with the one-upmanship with you. I say brown,

you get black fuzz. If I'd said black fuzz, you'd talk about how you once had firebreating radioactive lizards coming out of it. I say I have pneumonia, you say you had double-pneumonia. I say I killed Wilford Brimley with the door of a smashed up '57 Chevy, you say you were anally probed with bottle rockets by the entire cast of CATS every night for 12 years.

:cry::cry::cry::cry::cry:

[Schema Thing]

9. the latter

in my case.


Back on topic, isn't green tea supposed to be one of the best anti-oxidants? You'd think it would last longer before oxidizing. :think:

[Placebo]

10. Your tea was personally brewed for you by the Emperor of Japan...

I'm having tea and crumpets with Hugo Chávez, Hamid Karzai, Alan Greenspan, Michael Stipe, and Cindy Sheehan on their super secret island called "Isla Fubar".

Did I mention that Bono will be dropping in, literally, on a Hummer dropped via parachute from an American Cargo plane on its way to Iraq? And did I mention he will be delivering us some $500 per pair AIDS jeans? Yeah, I guess I forgot.

I'm just sayin', God.

[Rabrrrrrr]

11. OMG! I actually win one! You get stuck Michael Stipe!

:P

YAY! Finally, i come off better than Placebo!

God, I'm sorry you have to spend the afternoon with such great people and have it ruined by him. How sad for you.

[GoddessOfGuinness]

12. Maybe the anti-oxidants are oxidizing

?:shrug:?

[Callalily]

13. According to this

it really shouldn't be turning brown. Maybe it's a (ahem) low grade tea.

http://www.taiyointernational.com/GTNC/GTNC_HealthBenefits.asp

[Rabrrrrrr]

15. The leaves aren't - it's the liquid after I brewed it.

And I think the others are right - it's the oxidization.

[Neoma]

14. I've noticed that also.