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Comment by pergadad | Hacker News Reader

My local tea shop tells me it's easy to get near caffeine-free tea: as caffeine goes quickly into the water you simply pour water once, let it sit for 3-10 seconds and then throw the water out and pour fresh water on the leaves. I've not done any kind of scientific test on this but when I do it I get the impression that there is definitely an effect.

I'm wondering if that's a possibly unrecognised effect of the Japanese/Chinese "washing of leaves" before use - I always got the impression that's mainly something they do with Pu Errh tea (which has to "age" for years and is thus dusty) = because they don't trust that the leaves are clean.

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Check out this blog post[0] for data on at-home decaffeination by steeping. It requires a much longer steep than most people think.

Related note: An interesting paper[1] found "no observable trend in caffeine concentration due to the variety of tea", meaning that green tea doesn't necessarily have less caffeine than black tea, for example.

[0] https://chadao.blogspot.com/2008/02/caffeine-and-tea-myth-an...

[1] https://academic.oup.com/jat/article/32/8/702/829967

Green teas have about the same amount of caffeine. If anything, they'd have more since they are less processed. But as prepared, they have a lot less because they are steeped for shorter periods of time and with cooler water.

> If anything, they'd have more since they are less processed.

white tea seems to say otherwise..

White tea has such little caffeine because it is steeped for only a few seconds at a low temperature. Again, it's the difference in preparation methods rather than the leaf.

MYTH Sadly

The Truth Behind DIY Decaf Science has not only disproves the idea that you can make naturally decaffeinated tea with a hot water rinse but, worse yet, studies have shown that this kind of preparation method removes many of the antioxidants, but very little of the caffeine.

https://www.thespruceeats.com/how-to-naturally-decaffeinate-...

Then it seems like the obvious conclusion would be... to do the exact opposite?

Steep the tea for just 30 seconds and then drink that? Because then you'd get most of the antioxidants and very little caffeine? (And a very decent amount of flavor, even if it's not the full palette -- plus very few tannins.)

But then it'd taste like water. The idea is also for it to taste like good tea.

Why are you worried about antioxidants being removed? I thought that the supposed health benefits of antioxidants had turned out to be mostly not what we thought.

The same behavior can also be exploited for the inverse effect. Solubility of caffeine in water is greatly boosted with temperature. Many of the bitter compounds in tea extract at a comparatively slower rate, particularly as temps approach 100°C. If you want a caffeine hit with a decent flavour steep a high number of tea bags in boiling water for very short amount of time.

https://en.wikipedia.org/wiki/Chifir

in china this process is known as 工夫茶 (gongfu cha). You can also get upwards of 10 brews from good quality oolong.

My dealer (Taiwanese, direct importer) confessed that she doesn’t even use the accoutrements any more. She just puts the leaves in a cup and refills it when it’s half empty. I can get at least half a day out of a serving of leaves with black or any good green tea.

Interesting little effect of this: the leaves reconstitute when you do this (better teas have whole leaves). By the time you dump it out the tea looks like leaves again.

For those looking for low-caffeine green teas: I recommend checking out twig teas. Twig teas taste awesome, yet because there's little caffeine in the twigs they have a very-low caffeine content. In Japan they are called karigane (or kukicha). I am pretty biased, as Karigane is my favorite tea... I'm pretty sure there are equivalent in mainland China or Taiwan?

Example of a karigane (disclaimer: I am a co-founder of Tomotcha): https://tomotcha.com/en/blog/2018-006-karigane/

Green tea can be infused several times. Usually, the caffeine is pretty much gone after the first round. Plus, with some teas, the finer nuances of taste only come out in the third or fourth infusion.

So if you want caffeine-free tea, you can use green tea and throw out the first infusion (or give it to somebody else).

> “There used to be an old Chinese saying when brewing oolong tea: 'The first brew is for your enemy, the second for the servant, the third for your wife, fourth for your mistress, the fifth for your business partner and the last you keep for yourself,” says Lovell.

From https://www.telegraph.co.uk/foodanddrink/10840876/The-art-of...

"the third for your wife, fourth for your mistress"

Cheeky :)

Very interesting to learn this, since I had always assumed the first brew to be the best. I wonder, does this make reusing teabags a good idea, as well?

> I wonder, does this make reusing teabags a good idea, as well?

For green tea and Oolong, I don't see why that should not work. I have not seen Oolong in bags, though, and green tea in bags is fairly rare in Germany. But it should work, for all I can tell.

It usually has to be pretty good tea for anything but the second infusion to have any taste left at all, in my experience.

Maybe my standards are just very low, but I have had a fairly consistent experience of getting decent second infusions out of fairly pedestrian teas. Maybe the timing has an impact on this, I rarely let my tea sit for more than 60-90 seconds, unless it's Oolong.

> I always got the impression that's mainly something they do with Pu Errh tea (which has to "age" for years and is thus dusty) = because they don't trust that the leaves are clean.

Isn't it also the normal chinese method for oolong? "Wash" brew once for a short time (a few seconds) to open up the leaves, then rebrew with small steeping increments (probably depends on the specific but the teas I got suggested 20~30s initial brewing — after the wash — and 5~10 seconds increment).

That's interesting, I've always brewed teas (even Chinese green teas) on the order of minutes, not seconds.

Perhaps I use low quality leaves or too few leaves, because if I steeped my tea for 20 seconds, I'd get vaguely tea-flavoured water, not tea.

With the Chinese method, you also have to use large amounts of tea - as in, the cup should be full of leaves, at least after they're opened from the brewing.

I believe that’s the official line but I can’t help noticing that it also gets the little bits of tea leaves that would be missed by the traditional straining method.

I’m fairly sure both are true.

I think it’s more the small quantities consumed and the l theanine taking the edge off.

But I’ve gotten buzzed off of this kind of tea at a tasting. That was about a dozen 1 oz cups of five different varieties (which means a lot of second and a couple of third steeps).

This makes me glad to know. I love tea but don’t need the caffeine every time.

Moby popularized this myth but re-steeping tea does nothing to reduce a tea's caffeine.

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