Add "unimodal" burrs or (and?) flow control kit? - Page 2

Recommendations for buyers and upgraders from the site's members.
erik82

#11: Post by erik82 »

transit wrote:But what about a needlevalve kit? this part has not been evoqued directly. Erik, you mentioned, long PI though. I'm not looking for massive crema not the thickest shot, buy like Erik over 1:2,5 it's not to my liking (because of texture/dilution and because it's too much liquid for me to enjoy).
You don't need long PI for massive crema just for better extraction of light roasts as they tend to extract harder and a longer PI works for that. Crema is mostly dependent on roast level where darker roasts give more crema and tend to be thicker. I don't know if you need a needle valve kit or not because I've got no experience with the LMLM but you should be fine like this. Just first try some superb beans and if it's good then you don't need to change anything. If in a year you feel you're really missing out on some stuff you can always do it afterwards.

For beans I agree with Jeff and I also love La Cabra and Coffee Collective. My preference is also towards washed coffees. I don't really like those experimental fermentations as, in my eyes, they all tend to taste the same as overly fermented coffee with some minor taste difference of origin instead of the other way around. This is why I tend to prefer Tim Wendelboe.

What also helped for me was to buy a Commandante for holidays and for somewhat darker roasts. I like the Commandante much more for everything darker then medium as the SSP burrs give great clarity but that's not always what is best. I also don't want 3 grinders in my house so that was the most convenient choice as it serves multiple purposes.

transit (original poster)

#12: Post by transit (original poster) »

I've already lowered the pressure, we'll see.
I neither want 3 grinders, and I have a comandante too, that I use for pour over at home and when I'm away, so good to hear. And yes, sure I prefer focusing on beans rather than on gear!
My best,
T.

erik82

#13: Post by erik82 »

Nice to hear, then you've got everything you need for now. Sometimes it's really fun to just grind with the Commandante for espresso and see how it tastes. Most of the time you'll immediately know that you're SSP burrs perform better. It should even give much better results for pourover also. I use my EG-1 for both espresso and pourover and with pourover it gives so much clarity and layers of taste.

Just focus on changing no more then one thing at a time and spend some time getting familiar with it. You've now lowered pressure so just try different beans and keep it like this for a while. It should give a very positive improvement.

And also don't forget to enjoy! Things can always be better but you've got really good equipment and should make better coffee then 95% of everyone. Sometimes it can be hard to just be happy as you're always striving for a better cup of coffee (which is good) and that can influnece the state of mind in a negative way. Then just take a step back and start enjoying again.

mathof

#14: Post by mathof »

Jeff wrote: My experience agrees with Erik's that getting away from "9 bar" shots can benefit well-roasted coffees. I'm running around 4-6 bar in the basket for most of my profiles, maybe with a brief peak a bit higher. One rough estimate is that there's a 1-bar drop, so 6 bar in the basket might be 7 bar on the gauge.
I have been reading for a few years that lower-than-9 bar-pressure is good for extracting light coffees. But no one ever says why it is better? Taste? Extraction yield? Something else?

My single-spring lever machine produces more-or-less the same pressure on each pull (around 9 bar according to the manufacturer), so I can't run tests to see for myself. On the other hand, I frequently pull ultra-light roasts from Scandinavian roasters with tasty and high EY results. (I put that down in large part to my Kafatek grinder.) Anyway, I'd appreciate being told the benefit(s) of utilising relatively low pressures on light roasts. Thanks.

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Jeff
Team HB

#15: Post by Jeff »

What follows is biased opinion, not proven fact.

On my E61 HX, I spent a long time trying out different OPV settings. I eventually selected around 8 bar on the gauge as seeming to provide me the most enjoyable shots across both the comfort blends and San Francisco area filter roasts I was pulling. This was probably around 10 years ago. I don't doubt that this choice adjusted my baseline for flavor.

For me and the coffees I generally pull as espresso (about half La Cabra, Tim Wendelbow, or Coffee Collective), I found that I was getting muted flavors or occasionally into cardboard-like flavors when the pressure was much over 8 bar in the basket on a DE1 across a number of different profiles. I found that not getting over somewhere around 4 bar in the basket produced tasty coffee, but not with the intensity that I associate with espresso. I'm reasonably confident of that choice. I am much less confident of a feeling that a brief peak in the 6-8 bar range can bring out some additional depth of flavor.

There is also Cameron's https://strivefortone.com/2020/09/19/lo ... -espresso/ which discusses some of the thinking around lower pressures leading to more repeatable shots. Whether you like "turbo shots" or not, I think there is a lot of value in understanding some of the "why" behind their development.

baldheadracing
Team HB

#16: Post by baldheadracing »

mathof wrote:I have been reading for a few years that lower-than-9 bar-pressure is good for extracting light coffees. But no one ever says why it is better? Taste? Extraction yield? Something else?
Different chemicals extract differently depending on temperature and pressure.

For example, one of the main bitter elements in coffee, caffeine, best extracts at around 9 bar - so if you want relatively less caffeine extracted (and thus less bitterness), then one option would be to extract at a lower pressure.
-"Good quality brings happiness as you use it" - Nobuho Miya, Kamasada

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Jake_G
Team HB

#17: Post by Jake_G »

A comment on my experience, preference, and opinions...

I also prefer light roast espresso over most anything else. Here's what's on bar right now:


My experience with flow profiling has been exceptionally positive, and I'll no doubt return to it sometime, but part of my way of processing things is to try then for extended periods of time. Pulling the flow control out forced me to find a brew pressure that allowed me to explore the coffees I like and put my biases aside. I would have told you prior to doing this that preinfusion was necessary to get the most out (it still might be) and that a declining pressure profile was necessary to avoid the shot speeding up dramatically after the first few grams of liquid are extracted.

After dropping to 6 bar, neither seems to be true in a meaningful way. If I were preinfusing at 3 bar until first drops or doing a Slayer-style pre-brew, I would probably find that I needed 5o lower my brew temperature a couple degrees to get the vibrant acidity back. Not having preinfusion at my disposal, I simply find my home base temperature to be 202 +/- 3°F instead of 200°F. Basically I pull everything 2 degrees hotter than I would otherwise.

With respect to flow running away on me, 6 bar just seems to work. I pull shots that are rarely longer than 1:2 for ratio and they are great. Now. I'm "cheating" with my big flat grinder, but the mythos burrs in the Lucca Atom 75 do pretty great, as well. They are a bit closer to the SSP 64HU burrs than my 98HU in the Ultra, but they still perform very nicely and produce a very balanced espresso with great body and character with the wide cast of filter roasts that I throw at them.

My opinion (which is not fact) is that 6 bar shots dialed in at higher temperatures are every bit as delicious as dynamic profiled shots. There are certainly differences, but I'm enjoying what I'm pulling now just as much as anything I had when I was profiling every shot. When I put the needle valve back in, I will probably find that there are things I prefer over where I'm at now, but I can guarantee you it will be in the land of diminishing returns.

Cheers!

- Jake
LMWDP #704

transit (original poster)

#18: Post by transit (original poster) »

caffeine, best extracts at around 9 bar - so if you want relatively less caffeine extracted (and thus less bitterness), then one option would be to extract at a lower pressure.
Is there any evidence of that? That's interesting.

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Jake_G
Team HB

#19: Post by Jake_G »

I too am curious.

With the (small) amount of research I've done on the subject of caffeine extraction, the info I've found suggested that caffeine is so soluble in water (from 20% to 66% in water as temperatures move from 80°C to 100°C according to this site) that the handful of milligrams that is present in an average dose of coffee for espresso (or any other brew method) need only "get wet" to fully extract.

As an aside, I haven't seen any compelling evidence to suggest that brew pressure actually has a substantial impact on extraction as a whole. In my working theory, thinking of extraction as the diffusion of soluble "stuff" in ground coffee particles into a solution of hot water, concentration gradients seem to me to be the driving factor. The expansion of this theory in my mind suggests that particle size (available surface area) and flow rate of fresh (temperature-controlled) solvent through the puck are the primary players. Pressure is just a side effect of the desired flow rate at the target particle size...

I surmise that pressure will have an impact on other qualities of the resulting beverage, like body (maybe), texture and definitely crema, but those things are not extraction per se. And obviously pressure has an impact on how the puck the compresses and limits flow, so limiting the pressure far enough to reduce puck compression will change how the puck flows, but again, I think the flow is the dominant factor for what gets extracted from the coffee particles.

If someone can point me to a paper where it is found that different compounds diffuse into a water solution at different pressures, please send me a link. Obviously partial pressures matter when talking about gas diffusion, but remember that the partial pressure is scaled by amount of stuff in the solvent. And since the coffee particles and the water are both at pressure, I don't see how this affects the transport of soluble compounds into the water.

Cheers!

- Jake
LMWDP #704

baldheadracing
Team HB

#20: Post by baldheadracing »

transit wrote:Is there any evidence of that? That's interesting.
For example, see chapter 28, Coffee in Health and Disease Prevention - Victor R. Preedy, 2014 (Google books link so you can preview it. Unfortunately it looks like they really reduced the pages that can be previewed compared to 2015:
https://books.google.ca/books/about/Cof ... edir_esc=y
There is also a pirated pdf out there of the book. Beware of hidden payloads.)

Chapter 27: Physicochemical Characteristics of Roasted Coffee - relates qualities of coffee to measurable chemicals (if you have a lab :-) )
Chapter 28: Espresso machines and coffee composition - "The usual espresso machine settings (92C and 9 bar) seems to be the best choice for extraction of caffeine, trigonelline, and nicotinic acid, especially from Robusta blend."

ETA: Freely-available PDF articles about the same experiments:
https://www.researchgate.net/publicatio ... _cultivars
https://www.researchgate.net/publicatio ... omposition
-"Good quality brings happiness as you use it" - Nobuho Miya, Kamasada