When dialing in, why is espresso weight so much more important than pour time? - Page 2

Beginner and pro baristas share tips and tricks for making espresso.

#11: Post by jpender »

But time does impact taste, if for no other reason than that it is a byproduct of the grind size chosen.

So what's the crossover point, in a rough sense, approximately, depending, etc.? That is, how many T seconds difference equals a difference of X grams?


#12: Post by Milligan »

I think it comes down to, for espresso, percolation is more impactful to taste than immersion/contact time. Percolation is water flowing past the coffee grinds and stripping (think eroding) them of their oils, aromatics, fines, and solubles. The more water that flows through, the more "erosion." Heat gives the percolation more energy while time allows for more diffusion and soluble availability. These are lesser effects than overall water quantity passing by.

There is an interplay between all the variables of course.

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#13: Post by Jake_G »

I think Tim hot the nail on the head.

With percolation, you are adding fresh solvent (brewing water) into a puck with ever-decreasing solids content. If the water flows through more slowly, you get more extraction, but there is some point as the water travels through the puck that it becomes so solids-laden that it doesn't really pick up any more solids no matter how much more time you give it.

Whereas every time you add another gram of fresh solvent to the top, you have a maximum concentration gradient at your disposal to encourage more solids to come out of their hiding places and join the party.

Changing contact time does chance the balance of flavors, but it really doesn't change the fundamentals of what the beverage is like yield does.
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#14: Post by jpender »

I mostly drink long blacks / americanos. I tend to dilute the shot to about 2% strength, give or take. So whether it's a 1:1, 1:2, or 1:3 shot I end up with the same sized beverage at the same concentration -- roughly. So for my purposes the ratio does not determine the dimensions of the drink. It does affect how it tastes. Some coffees simply come out better at particular ratios.

But time matters too. When a shot runs too fast or too slow I can taste that. I think everybody can. Time differences may be more forgiving if comparing seconds to grams but enough of a time difference matters as much as a certain ratio difference. At least in my experience.


#15: Post by coyote-1 »

Jeff wrote:Grind size, dose, and ratio seem to be "big" knobs that most people can easily control. Time becomes an output in this case.

You could fix time as an input and let ratio be your output. At least in my experience, I can more easily and repeatedly taste the difference in ratio than I can in time. Assuming you're extracting reasonably well, all shots will have about the same amount of "flavor" in them. A 1:3 ratio shot will taste significantly weaker, watered down, or less intense than will a 1:2 shot.
While that's true, it will still have the same flavor profile! It's like toothpaste. When you first put it on the brush it's stronger than after swirling around in your mouth with water for two minutes, but it is still nonetheless the same flavor. Whereas 20 seconds vs 40 seconds of brew time will result in different compounds being emphasized, taking you perhaps from sour to bitter. And that will occur regardless of brew ratio. 3:1 will be weaker bitter than 2:1, but it will still be bitter.

With time as an essentially fixed input, the output amount comes out roughly the same from shot to shot anyway. It fills the cup to X line. Which means my ratios are always within a close range! So I'm finding time to be my golden guide. Especially since I'm routinely getting very good shots.

Don't worry yourself about the latest trend. If you've found time is what works for you, go with it.


#16: Post by crwper »

Just wanted to add one more way of looking at things. I'm going to summarize what I said in a post here:

https://quantitativecafe.com/2021/11/07 ... rol-chart/

In short, we can map extraction using something called a brewing control chart, where the horizontal axis is extraction yield (EY)--i.e., how much soluble coffee you've removed from the puck--and the vertical axis is total dissolved solids (TDS)--i.e., the concentration of dissolved solids in your coffee. From a sensory perspective, EY is most closely tied to the flavour profile of the shot, and TDS is most closely tied to the texture.

For any given espresso shot, we can measure EY and TDS to locate it on the brewing control chart, like this:

Brew ratio corresponds with slope in the chart, so as long as the brew ratio stays the same, we have to stay on the same radial line. We wind up exploring lines that look like this:

So, if we hold brew ratio constant and adjust the grind setting to change the shot time, we get a predictable change. Up to a point, grinding finer will result in more extraction and more texture, and grinding coarser will result in less extraction and less texture.

If, instead, we hold dose and grind setting constant, but let the shot run shorter/longer, we get a different motion in the chart. In this case, instead of moving along radial lines, roughly speaking we move around the origin:

Again, it's a progression that's pretty easy to predict--as you let the shot run longer, you get a more complete extraction, but less texture. However, the relationship isn't quite as simple as it was when we held brew ratio constant.

Finally, if we hold dose and time constant, then adjust grind setting to change the brew ratio, we would follow some mixture of these curves, and I think the shape of the curve would depend quite a lot, e.g., on the properties of the specific coffee we're using. It would be difficult to predict the effect of a change in brew ratio in terms of position in the brewing control chart.

So, if we want to make it as easy as possible to predict the effect of a change, it's best to hold brew ratio constant and adjust the grind setting to change the shot time. If we can't quite get what we're looking for, we just choose a new brew ratio (a different "spoke" in the plot above) and try again.
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#17: Post by jpender »

Very nicely illustrated.

Now suppose, like I try to do, you dilute each shot to the same final concentration. Then the effect of changing the grind or changing the ratio is qualitatively the same: the extraction changes. I don't think the taste change is exactly the same between those two types of adjustment for identical changes in extraction, but to a first approximation they both do the same thing. The quantitative side of that is harder to determine. But I can't be the only one who pulls a longer ratio than planned when a shot is running faster than expected.


#18: Post by crwper »

Fair point. There are lots of ways to move around the map.

Once you've chosen a dose, ground the coffee, and started the extraction, with traditional equipment your only real variable is shot time, so cutting the shot short or running it a bit longer is a good way to make on-the-fly adjustments if something's gone wrong. In that case, you're stuck on one of the curves in the last plot, so you can't increase both EY and TDS, but you can "rescue" the shot by letting it run a little longer, which will increase EY at the cost of lower TDS.

Let's say the first shot followed the orange curve, and you let it run long because it was going a little faster than expected. You might find that the taste is good but it's just a little weaker than you had hoped for. In that case, you could grind a little finer to push yourself out to the green curve, then reduce the time to get the same EY as before. On the plot, the change would look like this:

In my mind, this kind of navigation is more about "fine tuning" or "rescuing" shots that didn't go as expected. Usually, I'll start with a dose and ratio in mind, then adjust time to get the best result. Once I've got that, I'll switch to "fine tuning" mode and make small changes to things like brew ratio to explore further.


#19: Post by coyote-1 »

What if you hold both time and bean dose approximately constant? And the only thing varying is yield in the cup (ratio)?

From a non-theoretical perspective, I just did exactly this. Varied only the flow, to reduce the output. And I got what I expected: the same flavor profile as yesterday's shot, just more concentrated.


#20: Post by espressoren »

oscarnyc wrote:Thanks. Perhaps I should have made a more specific example to avoid some confusion: I'd say the most generic dial in recipe I see is an 18/36 that should fall around 27 seconds or so, with people acutely fixing on the weight and letting the time float +/- 3-5 seconds.

An alternative would be to focus at 27 second with an end weight that fluctuates between say 33-37 grams.

Everyone seems to have settled on option 1 as being the only way to do it, and I'm curious as to why. Is a 4g variance in end weight really that much more impactful than a 6 second variance in time for what is the same end goal (a well balanced normale )
I sort of do this, though I agree that a 10% or more change in output like you're talking about is a big shift. If the roast is lighter or tends to come out acidic I might do 20g in and 45g out in 25 seconds. If the roast is dark or on the bitter side I might shoot for 36-38g out in 25 seconds for the same 20g dose. It's enough to shift the sourness or bitterness away, but I don't sweat it too much if it takes 28 or 23 seconds instead of 25.