I was making myself some black tea this afternoon, and I looked down at my enormous (like 20 oz) mug and thought, “Yikes, if I drink this much tea I won’t be able to sleep. I should get a smaller mug for work.”
But then it occurred to me: if I use the same teabag in a 10 oz mug, will I be drinking significantly less caffeine? Since the caffeine’s in the tea leaves, not in the water, reducing the amount of water I use to make the tea won’t cut down on the caffeine.
It might cut down to some degree, since it presumably won’t dissolve quite as effectively. But are we talking like a 2% reduction in caffeine, or a 50% reduction?
That study found a large increase in caffeine when steeping the same size tea bag in just a slightly larger mug (6 vs 8 oz). If I’m reading that right.
So yes, AAUI a larger mug greatly increases the efficiency of caffeine extraction from the tea leaves.
Looking closer, the difference was large for short steep times (1 minute). For longer steep times (5 minutes) the difference was smaller. Which seems to make sense. Since there’s a finite amount of caffeine in the tea bag to be extracted.
Short steep times as well as a small mug would be the best way to reduce the cafffeine content.
6 oz to 8 oz isn’t the same thing as 10 oz to 20 oz. As I understand it, the caffeine dissolves very quickly, so by the end of a normal brewing time, either the caffeine in the water will be saturated, or the leaves will be out of caffeine. There is some mug size, then, at which the caffeine just barely saturates. For any size smaller than that critical size, then, size would matter, but for any size above, it wouldn’t.
I don’t think tea comes anywhere close to saturation of the caffeine concentration, given that there exist other beverages with much higher caffeine concentrations.
So all of the caffeine in the tea bag will eventually dissolve in the mug.
The article says a serving of tea leaves contains 55mg of caffeine and “there were no observable trends with the different tea varieties” (although the table shows a lower amount for the Twinings brand). So that will ultimately be the amount of caffeine in the mug.
The article does show the effect of the steeping time. For a short steeping time not all of the caffeine will have time to dissolve. But there are large differences in dissolution speeds between brands (again, if I read that article right) and some difference in dissolution speed depending on mug size.
Alas, the article did not test 10oz and 20oz mugs, only 6oz and for some cases 8oz.
True; you’d need an awfully small water:tea ratio to match the concentration in some of the modern energy drinks.
I’m surprised the steeping time would matter so much, though: I’d always heard that the caffeine mostly dissolves as soon as you dip the bag in the water, and that you could make lower-caffeine tea by dipping once, pouring out that water, and making a cup with what was left in the bag.
Well, it seems Tazo Awake does exactly that. Hmmm, what’s in a name?
I’m quite surprised by the difference between brands. Tazo Awake is fully dissolved within one minute even in a 6oz cup. It’s the only brand that does that.
The second fastest is Tazo Earl Grey which is two-thirds dissolved after one minute. No other brand comes close to even that speed.
For another comparison, Stash Darjeeling Black dissolves at half the speed of Stash Earl Grey Black. The former is one-quarter dissolved after one minute, the latter half dissolved.
With these two you see the difference in speed for mug size. Stash Darjeeling Black is only half dissolved in a 6oz cup even after 5 minutes, but over two thirds dissolved if you use a 8oz cup.
I think it’s dependent on two things (they’re both mentioned up thread, but not in conjunction with each other).
First, there’s a finite amount of caffeine in a tea leaf. So let’s say you extract all the caffeine from 1/2 oz of tea leaves. Let’s call that 50 mg (finding out the caffeine content of unbrewed tea has proven difficult).
If you were to brew your tea in such a way that all the caffeine was extracted, it wouldn’t matter if you had brewed a 4 oz or an 8 oz cup- both would have that same 50 mg of caffeine. However, let’s say you brew a 32 oz pot of tea holding 2 oz of tea leaves. That gives you 200 mg of caffeine in the entire pot. So if you pour yourself a 4 oz cup, you’ll only have 25 mg of caffeine in that cup, and correspondingly if you have a 8 oz cup, you’ll have 50 mg again.
But… you can brew tea stronger- if you doubled the amount of tea, you’d have stronger tea- 400 mg of caffeine, and your per-cup amounts would increase. Similarly, if you brewed your 32 oz pot with 1 oz of tea leaves, you’d only have 100 mg and your per-cup amounts would be halved.
Steeping times and corresponding extraction rates are probably very hard to standardize- they’re going to be dependent on water temperature, what your tea leaves are contained (or not) in, agitation, etc… so I’m using the assumption that you’re doing the steeping exactly the same for each cup or pot above.
Well, the way I make tea, with 20 ounces of water I would use… about a dozen tea bags? Many teas can be infused more than once, so you don’t necessarily need to use all the water (and proportionally large amount of tea leaves) at once.