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Permalink Reply by Jeremy Gray on March 23, 2011 at 3:07pm

No

Do you?

Jason Haeger said:

Understood.  So do you re-program each group-head every day to compensate for the age of the coffee?

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Permalink Reply by Jason Haeger on March 23, 2011 at 3:08pm

I don't use volumetric dosing.  :/

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Permalink Reply by Jeremy Gray on March 23, 2011 at 3:34pm

I don't either.

I also have never heard that the amount of water needed for a specific coffee would change each day as it ages. If your adjusting grind and refining dose to meet the flavor profile that should be expected, which I'm sure your doing, then how would the amount of water play into that? And I'm really serious, there is no sarcasm here. I have never heard of this. In my experience, when using a volumetric extraction, when something was off in the shot based on the volume set. It was grind or dose as the culprit. Stopping the extraction sooner or letting it go longer wouldn't have helped much, they all work together.

Please explain the - aging coffee:amount of water 

 

 

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Permalink Reply by Brady on March 23, 2011 at 5:45pm

OK, I'm a little confused here. It reads (here and in the bits that follow) kinda like you are saying that you see WBC competitors using a program button? That can't be what you're saying, though... because the current and former WBC machines are semi-auto with no programmed buttons. They are not volumetric machines and have no flowmeters. Just trying to clear things up a bit.

 

On the larger point, the vast majority of the excellent espressos that I've been served were made by a well-trained barista using the "manual dispense" function or a semi-auto (non-programmed) machine. However, several of these shots have been made by an equally well-trained barista using a programmed button.

 

While I think that this speaks more to the mindset of the owner and staff than any machine aspect, the observation remains the same... if I am served a great shot, it was probably made on a semi-auto machine.

Jeremy Gray said:

I think it's pretty interesting that the general consensus is that using the programmed button leads to lower quality. So all one would have to do to win at the WBC is manually pull the shot? Very few(if any, I didn't see every one) of the contestant's I watched were doing it that way. 

 

My point is, it's a bit ignorant to say that quality is lower when using the volumetric button. Could it be lower? Yes   Always lower? No way 

Could the fact exist that the Barista still has a choice to serve a shot they let run a little long while pulling manually? yes  or automatically? yes

I guess this discussion will eventually lead to the fact that we should all be using Lever machines as well, cause we surely shouldn't be letting the machine do the work that the Barista should be doing. Right?

 

 

 

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Permalink Reply by Jason Haeger on March 23, 2011 at 8:28pm

The amount of carbon dioxide in the coffee will have a drastic effect on the rate of extraction since Hot H2O + CO2 = H2CO3(otherwise known as carbonic acid). 

 

Carbon dioxide is also a binder of aromatics, which means that the older the coffee gets, the less desirable matter is present in the coffee.  You can compensate for this, as many do, by slightly adjusting the dose.  Dosing more or less coffee will effect many things, including but not limited to volume of water.  

 

Do a little experimenting with this over time.  You may find that the same water volume yields the best result with the most consistency over time, but unless you've taken away the crutch, how can you be sure?  

 

I also concede to the fact that not every coffee (or blend of coffees) or roast profile (or blend of roast profiles) behaves the same way, and it is possible that while my espresso does prefer a little (subtle) tweaking over time, yours does not.  

 

That having been said, my experience over time has matched Brady's.  The best shots I have ever been served have not only been non-volumetric, but they were also using MacGuyver-like techniques with the machine.  

 

I have tried the volumetric dosing in the past.  While it was easy to produce consistently passable espresso, I noticed that the consistency wasn't as consistent as when the volumetric dosing was NOT used.  Maybe It was because I wasn't using a $2K conical grinder.  Maybe it was because I wasn't using a La Marzocco Linea (the GB5 didn't exist yet).  Maybe it was the coffee.  Maybe it was me.  In any case, I was able to get better quality more consistently when I trusted my own instincts and disregarded the built-in volumetric dosing feature in favor of the continuous flow button. 

 

This topic is just like any other: YMMV

Jeremy Gray said:

I don't either.

I also have never heard that the amount of water needed for a specific coffee would change each day as it ages. If your adjusting grind and refining dose to meet the flavor profile that should be expected, which I'm sure your doing, then how would the amount of water play into that? And I'm really serious, there is no sarcasm here. I have never heard of this. In my experience, when using a volumetric extraction, when something was off in the shot based on the volume set. It was grind or dose as the culprit. Stopping the extraction sooner or letting it go longer wouldn't have helped much, they all work together.

Please explain the - aging coffee:amount of water 

 

 

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Permalink Reply by Jeremy Gray on March 23, 2011 at 8:58pm

Thanks for explaining. I will definitely play with this to see how volume affects aging. I have read about the effects of dosing more and less, and adjusting temperatures up and down. but have never read anything about messing with volume. Maybe because it happens naturally, as you said with trusting your instinct rather than relying on what the machine produces. So I guess I have something new to test. Thanks again.

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Permalink Reply by Jacob Casella on March 24, 2011 at 2:33pm

Re: crema, age, and volume. I always notice lots more crema volume off fresh beans, say in the first 3 days out of the roaster. They often have sharper, sometimes more astringent or woody flavors (even after letting the crema settle/stirring or scooping it off). I had been assuming that the extra carbon dioxide is causing a higher rate of extraction as they are driven out of the bean fragments--but now I'm wondering about the carbonic acid component as well. I am not sure how adjusting volume could affect this--would you want to pull a larger or smaller volume from the same dose of coffee to adjust for the extra co2?

I've considered making a volumetric adjustment part of the morning dial-in, but until a few dozen areas are mastered by all my baristas, I don't think it's the biggest place we can improve quality. Especially since I'm not sure what I could do by changing volumes that I couldn't do by adjusting dose and grind. I like to think that I only need to introduce an inconsistent variable (like manually stopping shots, thus making the volume/brew times inconsistent) to account for some other area of inconsistency. Other things being equal, I'd like to get all my variables as consistent as possible, and then only put the wrenches on one or two (grind, and dose), to deal with changes in the beans.

Anyone have any thoughts on why it might be more helpful to to control the time & volume side of the equation (for a given dose/grind), instead of adjusting grind for a given dose/volume?

I used to give a lot more credit to my mystic barista spidey sense for manually pulling shots. Then I got really into consistent dosing--when I first started using a gram scale dozens of time a shift, it was really humbling to see how much inconsistency I was introducing. When I was manually pulling shots instead of using the volumetric controls, I was compensating for inconsistencies in my technique at least as much as for variance in the beans themselves. Dosing consistently, using an AV button to control volume, and seeing all my shots fall within a second or two of each other and tasting good-- that's really what makes me interested in using good volumetric controls. To decide a shot needs to be stopped based on appearance and hit the button at the exact same time that the machine is cutting it based on volume is particularly gratifying (although I have to yelp and pull the cup out before the weird second extraction starts). I see some of my baristas do that constantly.

(Incidentally, shots pulled with volumetric controls through a spent puck often take the same amount of time to pull, within a second or two, which I feel like should be telling me something about fines migration or other resistance issues.)

Good discussion, btw. My current positive and negative feelings about volumetric controls are both pragmatic- I work at a shop with 20oz quadshot mocha rushes, lines out the door sometimes, and being able to rely on the volumetrics are a definite help in those circumstances. On the negative side, I'm sure volumetric-assisted laziness is a contributing factor in the dismal state of most espresso. All that said, volumetric controls are something I want in my toolbox, and I'd love to see machines that put in volumetric controls for a specialty barista instead of just for convenience.

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Permalink Reply by R. Justin Shepherd on March 24, 2011 at 7:34pm

I tend to agree with Jacob, though I'm admittedly more concerned about a 9/10 quality and 10/10 customer service ratio than anything else. 

 

Interestingly re: volumetrics flowmeters, when my Aurelia V was installed today, I had the tech explain to me how the volumetrics on this particular machine work; though it's not this way on all machines, the Aurelia is designed with flowmeter way BEFORE the grouphead, and as you pull your shot and the grouphead boiler releases and fills simultaneously, the flowmeter measures the amount of water it is sending to the boiler — in other words, the water you're getting to the group in the shot isn't being routed through a maze of little pipes first. From what I could test today, via programming those buttons and then pulling with those buttons afterwards, shot quality did not deteriorate a bit; however, the science Jason is putting forward sounds solid and reasonable enough, so I'll be interested to try the experiment a few more times, especially when I'm getting near the end of my recent shipment of 'spro that will probably be about 9-11 days old at that point (it's about 3 now). 

 

BUT. For what it's worth, I told my baristas that I haven't programmed the volumetrics yet (not exactly true), and that they need to be using the manual pull for every shot or risk major problems. I'm still undecided whether I ever let them in on the secret. 

 

PS: NS' translation of the Italian instruction manual into English is just god-awful, so if anyone has an Aurelia V and wants to tell me how to program the automated backflushing cycle or the on/off on the cupwarmer... well, I won't complain.

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