So, I’ve had one of these for a couple of years, and I always press the “strong” button, and it does taste pretty strong. Not as strong as an auto drip when I load the filter, but strong enough. The only thing I can thing I can think that it could do is to run the water more slowly through the cup when you press “strong.” Is that what is does? Or is it just a placebo button?
The one in my office just uses different different volumes of water for the three different options. Maybe yours is newer and does something different.
Thanks! and yeah, mine has a volume setting, so it must be releasing the water more slowly. It supposedly can make 8oz “regular” or “strong.” If I want more caffeine, I just put half a No-Doz in the pod.
Thanks for the link-I was just wondering the same thing.
Does it have a treble & bass setting too or a full equalizer?
I would think that having the water spend more time with the grounds would make it bitter in addition to stronger. That’s the problem with people that make strong coffee. Too little coffee for the water.
There’s a fair amount of latitude between the modern methods (filter drip or Keurig) that only has the water in contact with the coffee for a few seconds and the older methods of a percolator or pouring the liquid through the ground coffee a second time. The strong button only increases that period of contact somewhat, not all the way to bitter.
My Krups drip coffeemaker has a similar button for “1-3 cups.” I still haven’t figured out just what it does, technically, as i doesn’t make the water flow sound any different—but I do think the coffee is more to my [strong] taste.
Is there really no connection between the taste of coffee (its “strength”/bitterness/boldness/whatever) and caffeine content? It seems to me that steeping time should affect caffeine content somewhat, no…?
Caffeine has a distinct taste, but there are different species of coffee, like “robusta” which has a slightly higher caffeine content, and flavours will vary depending on how the beans are blended and roasted, so you could have an extremely strong yet smooth cup.
IME with coffee pod machines (Italian, though, not Keurig) you get strong coffee by buying the (finely ground espresso) blend labelled strength 10 on a scale from 1 to 10, and hit the “ristretto” button which uses half as much water, around 30 ml. It is not steeped longer. If it’s not enough coffee, just repeat the entire process 2 or 3 times 
Don’t think I’ve ever tried more than a quadruple espresso, though…
ETA caffeine has a bitter taste of its own, but coffee is not pure caffeine, so it is hardly the only component of the flavor, “body”, “finish”, and so on
That helps, thanks.
But for any given input of beans (same qty and type), does the amount of water and/or steep time affect caffeine content? On my machine, there are 3 cup sizes (ristretto/espresso/“coffee”). As far as I can tell it uses the same quantity of beans, but each cup size is bigger and has more water and tastes different. Do they have meaningfully different levels of caffeine, too, or is it really just extra water?
What’s confusing to me is that it seems to be pumping out coffee-looking water the whole time, as opposed to just pumping coffee at first and plain water later. So whether it’s “steeping” or “steaming” or whatever it is espresso machines do while they’re making coffee, does that duration add more caffeine…?
That is a good question, complicated in practice by the fact that the shorter coffees are not simply made with less water, but are also ground a bit finer (thus exposing more surface) while the flow of water is slowed down, so the brewing/steeping still takes 20 seconds or so even though half the amount of water is used. So maybe the ristretto ends up with [ **WARNING: completely made up placeholder bullshit number] 2/3 the caffeine content of a “normal” espresso. A long coffee takes longer to brew, using more water.
Now, if you think about it, the longer the grounds are brewed, the more caffeine is extracted (although at a diminishing rate) as well as other, both desirable and undesirable, flavor components. This is where we need some hard data for the various chemicals and I won’t fabricate data. ISTM most of the caffeine is extracted first so that the “ristretto” has more per ml (but not twice as much) and less of the other bitter compounds, while with the normal setting you get a larger total dose of caffeine, but the flavor profile will be different. This will be become even more extreme when you go to the “lungo” setting, until at some point the brew will end up tasting bitter but also thinned-out. All this is complicated, like I said, by the fact that the “lungo” blend will have been ground differently in the first place. So we really need actual measurements from an actual espresso machine…
SUMMARY: it’s not simply more water. (I mean, you could dilute it by dumping water in afterwards, but why bother?) It’s more water, more total caffeine, and more other compounds, resulting in a slightly weaker yet more bitter drink.
When I want the jolt cola version of coffee, I put 1/2 a No-Doz (actually, it’s a cheaper off-brand) in the pod. It doesn’t make it taste more bitter. It gives it a slightly tangy taste it I use a whole pill, but that’s too much caffeine, anyway. 1/2 a pill increases the caffeine content by about 50% (so instead of approx. 200mg, there’s 300mg-- albeit, I doubt the whole pill gets dissolved, so really, it’s probably more like 250-275mg) without altering the taste noticeably. It’s the same jolt as a really strong cup made from double grounds in a drip filter, without having to load it up with whole milk & Splenda & syrups to make it palatable.
300 mg sounds like much more than in the double espresso/ristretto I was talking about, so if adding 50% more pure caffeine does not alter your taste much, that is evidence that caffeine may not be the primary component of even unpalatably bitter coffee, which is what I was saying. (But personally I find the taste of low- or de-caffeinated coffee different from that of strong coffee, and not necessarily in a good way.)
BTW I like caffe latte as much as anybody, but the coffee itself should be perfectly palatable by itself without any sugar, milk, lemon, cardamom… then again, I never tried mixing half a gram of pure caffeine into a 30 ml single espresso and tasting the resulting drink. If the fresh coffee comes out unpalatable, then (this is an opinion, of course) it was not roasted correctly (it happens!)
I don’t think a caffeine pill is “pure” caffeine. You can get pure caffeine powder, and it’s notorious for inducing heart attacks in healthy people. The pills have binders and fillers in them. My bottle say "inactive ingredients: calcium stearate, lactose, microcrystalline cellulose, silicone dioxide. I think those keep it in a solid pill form, make it look white, keep it absorbable, and help it break down evenly in your stomach. The calcium may also keep it from giving you indigestion. The lactose may even be a coating on it so it isn’t so bitter when you pop it in your mouth, but that’s a WAG. However, I do know that lots of bitter pills have coatings on them.
That setting is typically for the temperature of the hotplate that the carafe sits on. The “1-3 cups” selection sets the temperature a little lower.
Huh. While that makes some sense, doesn’t every pot of coffee reach that level pretty quickly anyway?
Wow, seriously fascinating. And here I thought coffee was just tropical cancer beans + hot water 
Thanks for that detailed explanation. I’ll have to do more learning and taste-testing here…
I have never encountered this nor expect coffee to be served in this way, but under images of “ristretto” there is a picture of what appears to be a shot of espresso served with the first half and second half separate. So, I never tried this experiment, but you could do the same thing at home by running your espresso machine and changing cups every 10-15 seconds. Then you could taste-test each stage directly.
The small glass of water in the picture is commonly served in cafés along with coffee, by the way, and so is a tiny chocolate or macaroon. But I have never anywhere had them offer to split the shot into two or three— maybe I do not frequent fancy enough cafés. Nor have I ever received a little card detailing the exact blend like that— if I particularly like the coffee I just ask what they use; typically it is an Italian roast like Illy or Lavazza.
A pill of pure caffeine would not be a good idea. The LD50 of caffeine (dose that kills half the people who take it) is about 10-15 grams. That’s about 75-100 cups of coffee.
Yeah. You can buy it on the internet in powdered form, and lots of teens have killed themselves by thinking that 50mg and 50g are the same thing, because 50g of powdered pure caffeine looks like about the same amount as a crushed 1/2 No-Doz (or Jet Alert, whatever-- that’s what I actually have-- much cheaper).