Tea after brewing

[Wholemeal Crank]

A comment or two in another topic, and my experience yesterday with a black tea drunk over 8 hours or so have got me wondering: are there predictable changes that occur in brewed tea when it sits before you drink it?

Most of the tea I drink at work is of necessity brewed 'in bulk', and carried around in a quart thermos and sipped through the day.

Yesterday, I was brewing some yunnan black tea, and remembering that black teas give up most of their flavor more quickly than oolongs and puerhs, I used a higher leaf to water ratio to account for fewer reinfusions, and I overdid it. The lovely fruity flavor of this tea was a little overwhelmed by tannins--my expresso-quaffing boss even commented on it's expresso-like qualities when he had a cup immediately after I brewed it.

But by evening, I was no longer noticing any of that bitterness--just the best parts of the tea flavor were left. So, now I'm wondering: were my tastebuds adapting over the course of the day? Were the tannins in the tea depositing on the sides of the thermos? Do the tea elements recombine or decompose during the course of the day?

And earlier in the week I brewed a thermos of some silver-needle white tea that gradually seemed to lose flavor in a way that the oolongs and pu-erhs generally don't--it just seemed less sprightly.

I know my thermos marathons are not giving my teas their best chance to shine, but the very existence of tea cozies implies a long tradition of other people sometimes needing to do the same thing.

Have you ever noticed changes like these in teas you delayed drinking after infusing?

[velveeta]

It seems to me that tea that has been sitting for a while after brewing almost needs a decanting - to remove that filmy deposit that forms on the sides of the cup or pot and the slightly crusty filmy same deposit on top (like ice forming on a pond). This deposit surely must contain flavoring compounds. Is it the tannins as you mentioned or was that just a guess?

How best then to filter aged in the cup tea. I am thinking cheesecloth.

I agree on the mellowness of aged brewed tea, it often goes into the fridge if it is not drunk and then used as iced or cool tea the next day.

My tea sometimes gets re-microwaved many times as I follow my cup around the house and forget to drink it while it's hot. This just seems pretty abusive to the tea, it gets nasty quickly.

[cdh]

Oxidation definitely happens. Brew a cup of green tea and leave it out overnight. It will both look and taste much more like a black tea.

[Wholemeal Crank]

I've only resorted to microwaving a couple of times; usually if the tea gets cold I just drink it veryveryfast or dump it.

And of course I will now make some of the less-fabulous green tea in the back of the cabinet and let it sit out overnight. Probably should also set out some black tea, and photograph the befores and afters, in little white cups.

[Wholemeal Crank]

Two accidental tests of what happens to tea after brewing this week: made a thermos of very nice sweet gyokuro, that over the course of four hours both turned from green to gold and lost virtually all of its sweetness, although the liquor body remained thick and silky; and last night, had to abandon a portion of a cup of Tie Guan Yin, the very sweet and lovely spring diamond grade 2009 from norbu, and it had not changed its golden color noticeably, but did lose the sweetness entirely.

Now setting up a more proper experiment.

[Wholemeal Crank]

Didn't take very long to see a difference!