Origin and Purpose of Doser

Grinders are one of the keys to exceptional espresso. Discuss them here.
Anthony

#1: Post by Anthony »

I have recently heard (going back to the makers of Cimbali grinders) that the original purpose of the doser on the grinder was to allow the beans to degas (again) after grinding. Certainly, unattended grinds resting in the doser can get stale quickly. Yet, as I understand it, the thought was/is that 1) the change in the structure of the bean (i.e., through grinding) allows another process of degassing, 2) the doserless grinder does not allow the grinds to sit long enough (according to a specific "Italian" taste), and 3) beans need to degas more, namely, after grinding (again, according to this specific Italian taste).

This is not to say that the doser does not have other purposes, especially in commercial shops, or that the doserless grinder can be useful in the home (and from recent accounts is gaining in popularity as a home machine). Still, I am wondering if anyone has experientially observed this difference.

Anthony

CafSuperCharged

#2: Post by CafSuperCharged »

I am sure some of these hypotheses have been discussed in older home-barista threads.
That pertained mainly to the aging or maturing.
Statement 1) I would say is very logical, it is almost a tautology.
Of statement 2) I would say, it depends. If the assumption is degassing can only get to the proper point after grinding, then it would make sense if it were true.
Maturing or aging is well described (3), also in home-barista threads, but the question is if the grinding is required. Would 4 days after roasting and doser-grinding compare to e.g. 5 days old coffee?
This would be a nice experiment for home-roasters.

Italian bars have high volumes and the doser is almost required from that perspective as well. I have thought about the aging in the doser however.

Personally, I have a doserless grinder - guess what I do, at least with the morning coffee: grind into a glass that exactly fits the portafilter basket, let the grounds sit in the glass for about 20 minutes and then brew.
I originally introduced the glass as a way to improve distribution.

Regards
Peter

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another_jim
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#3: Post by another_jim »

A standard commercial doser holds 10 or 12 singles shots. A busy Italian bar will run a shot per minute per group, i.e. 3 to 4 singles per minute. So the coffee sits around for 3 to 4 minutes.

I'm pretty sure dosers were originally designed to dose.
Jim Schulman

CafSuperCharged

#4: Post by CafSuperCharged »

Actually, the amount of doses on the big grinders is more like 25 per completely filled doser chamber.
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I created the picture/table with data from the Mazzer website.
Higher volume Italian bars, which certainly does not constitute all of them, would all use the biggest size grinder. Probably even the medium volume bars that still would have considerable flow during the espresso rush hours.
The 14 grams in the Italian context is really realistic.

That said, Jim, you probably are right about assuming this was invented to dose, but you underestimate the Italian engineers' understanding of espresso coffee if you do not point to the aging/maturing quality that is added into the equation.

Regards
Peter

lolgun

#5: Post by lolgun »

CafSuperCharged wrote:. . .snip. . .
Italian bars have high volumes and the doser is almost required from that perspective as well. I have thought about the aging in the doser however.

Personally, I have a doserless grinder - guess what I do, at least with the morning coffee: grind into a glass that exactly fits the portafilter basket, let the grounds sit in the glass for about 20 minutes and then brew.
I originally introduced the glass as a way to improve distribution.

Regards
Peter
That's interesting because that's in contrast to The rule of fifteens and you would assume that the taste of your coffee has already begun to degrade.

CafSuperCharged

#6: Post by CafSuperCharged »

My observation of Turkish ground coffee that a friend gave me as a present from Istanbul was that it ages less fast.
My hypothesis then was that this is caused by the extreme fineness of the grounds (finer than espresso).
There would be much less evaporation from the coffee, even though particles have much larger surfaces, relatively, being smaller, and there would be less diffusion of air/oxygen into the grounds.

Using an Italian espresso blend, I target grinder setting at between 14 and 16 grams of coffee with leveling only, not tamping. That is, Italian style. Now the coffee is very fine, almost powder.
The morning coffee process being more organic, I cannot guarantee it is actually 20 minutes - it may be less, like 10-15.

In "the multi variable optimization space that is espresso coffee" there are so may variables/parameters that I would need seriously controlled experiments to be able to really make conclusive statements about impact on taste.

Regards
Peter

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another_jim
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#7: Post by another_jim »

Very cheap naturals are better stale, since their fermented and rioey tastes and aromas dissipate, while the generic cocoa and nut flavors, along with the caramels and sugars, are shelf stable. In other words, completely stale coffee is not "off," but a nondescript, mildly pleasant and inoffensive drink, much like slightly sweetened cocoa. That is is why many people like year old Italian espresso and gladly pay $15 per pound for it.

Terroir put on a demo where they cupped a flawless coffee ground 24 hours before against a baggy, past crop version of the same coffee ground fresh. The flawless stale coffee won. The moral they drew was that flawless coffee was so much better that it could even be ground a day ahead and still win. It took me a long time to figure out that had the baggy coffee been ground the day before too, it would have tied the flawless coffee, since the bad aromas would have dissipated from one, and the good aromas from the other.

Staleness is an equilibrium state in which all coffees are equally mediocre, no matter how good or bad they were to start out. If you are selling generic coffee, making it completely stale is a great way to ensure consistency and to cut raw material costs. Since most Italian espresso is generic, they stale it as a matter of course.

It takes about a week for ground coffee to stale completely; although since it's an exponential process, a day post grind (espresso fineness) will take care of a lot of the funk (or good aromas, if they are there). The problems is that the coffee sits in the doser far less long.

As for ground espresso getting noticeably worse in 5 minutes, or even 15 ... That's mostly US coffee pros doing their princess on the pea, more sensitive than thou, spiel. If they recommend to rest a coffee post roast for several days, grinding it and letting it sit for several hours does the same thing. The idea that resting whole bean coffee can sometimes be good, while resting grinds is always bad, is nonsense from the get go.

Abe and I put this to the test. A medium dark roasted espresso a few days post roast with robusta, aged coffee, or sumatra, i.e heavy on the roast flavors, improved when left to sit for an hour ground. A fragrant lightly roasted Yrg degraded.

However, all this doesn't change the fact that the amount of time coffee spends in the doser is entirely determined by the traffic in the cafe. So to say that the doser is engineered to provide some predictable measure of grind exposure has to be BS. Mostly, in Italy, doser time is not an issue, since the coffee is well staled before it is ground.

But that, of course, doesn't mean that the espresso manufacturers haven't been making claims like you report. The whole topic of coffee freshness is almost entirely made up of empty assertions, posturing, and obscurantism. Coffee is a market with lots of niches; each niche has its own freshness and storage practices, and each niche claims theirs is optimal. Therefore the claims contradict each other, and none make much sense.
Jim Schulman

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Whale

#8: Post by Whale »

Great post Jim, very thoughtful and thought provoking.

Although there are a few generalisation that I do not readily accept.

Italian coffee is not generic (at least to my differently educated palate) . There are tremendous differences in the taste of the varied Italian offering. They may all taste the same to some, on the basis of that what they give or what they do not give, is not what one is looking for. Even writing this, I cannot believe that anyone would perceive that a blend from the North and from the south taste the same.

Italian coffee is not stale by design. Although it is possible that some coffee producers are, if, as Jim eloquently report, staleness is purposefully used to reduce the aromatic effects of defects. But, certainly, based on the incredible demand from the public there, not ALL coffee served in Italy is ground from age old coffee. There a Italian consumers that do like fresh roasted coffee, and there are offerings that cater to them.
another_jim wrote:Abe and I put this to the test. A medium dark roasted espresso a few days post roast with robusta, aged coffee, or sumatra, i.e heavy on the roast flavors, improved when left to sit for an hour ground. A fragrant lightly roasted Yrg degraded.
Unless I am misunderstanding the above statement, it would imply that robusta, aged coffee or Sumatra are sub-premium coffee and that heavy on the roast flavor is a defect. While this may very well be true to a lot of espresso enthusiasts, the fact these types of coffee are in high demand and command a significant price is an indication that there are a few that actually believe that what they bring to the cup is desirable. The same argument could be made for darker roasting.

For my part, Lightly roasted Yirgacheffe IS the type of coffee/roast that I have to let mature/age/stale/calm, whatever you want to call it, before I can truly ENJOY it.
another_jim wrote:So to say that the doser is engineered to provide some predictable measure of grind exposure has to be BS. Mostly, in Italy, doser time is not an issue, since the coffee is well staled before it is ground.
To go back on topic, I do not think that it is implied to be a "predictable measure of grind exposure" but maybe just a means to apply some aging if one would desire to do so.

If a barista tastes the few first shots in the morning and decides that he would rather age the grind a bit, say 30 minutes. He fills the doser and let it sit there for that time. He then starts to use the doser and based on regular demand (this the Italian coffee bars have), the auto-refill feature of the grinder will somewhat ensure that the sitting in the doser for a while is accomplished. Essentially delaying usage with controlled first in first out. For a cafe that has more demand and would empty the doser quicker there would be a need for more than one grinder available.

There are a lot of posts on this forum where people state that they let the coffee sit after ground, I assume to improve the taste.

Of course this is speculation on my part, but I can see that it could be possible for someone to have though of that in the design process. Although I do believe, as well that the doser were created mostly for dosing and not having to wait for the grinder when the barista needs the coffee.
LMWDP #330

Be thankful for the small mercies in life.

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michaelbenis

#9: Post by michaelbenis »

A great debunking post there, Jim.

Sylvain, having lived in Italy for 10 years I'd agree that most Italian bars serve "generic" espresso. It's not a gourmet affair for most Italians, it's just one facet of everyday life. You bump into a friend, want a quick chat, so you pop into a bar and have a coffee. Or you make the colossal mistake of arriving early for an appointment, so you pop into the nearest bar, read the newspaper headlines or play the lottery and have a coffee. etc. etc. It punctuates the day nicely or makes a small occasion, like - dare I say it? - lighting up a cigarette. :shock:

You get what you expect. Not too bitter, not too bland, with a caffeine kick and a lingering aftertaste to see you on your way. The beans are bought in bulk to keep costs down. They're never particularly fresh or stale. And there may be other advantages to older coffee, which I have a hunch tends to be less affected by the weather in terms of how it grinds, so there's less of a challenge to the high volume of baristas who churn through. Just a few thwacks and the usual light upward tamp with usual fine grind will get reasonably consistent, acceptable results. End of story. It's a system that works - like the half-cooked pasta that's held waiting in busy restaurants: it won't be "al dente" but it won't be mush either, and no one will be kept waiting. Italians don't like waiting... :wink:

Which is what the doser panders to - it puts a buffer between the grinder and the barista, so there's always ground coffee ready to go. And there's the side effect of less noise. The grinder only runs now and again, not every time someone wants a shot - which is all the time in many Italian bars. And that also gives the burrs and motor some time to cool down. Most of these bars are sooo busy that staling in the grinder never comes into it, as Jim points out.

Final comment: the funny thing is that the Italian system works. It may not yield what the very best coffee shops can produce worldwide, but its consistency is admirable. There is more than one roaster I can think of that produces what I consider superior beans/blends/roasts but is not able to find the staff to consistently produce a superior cup in the coffee house annnexes to their roasteries.

Cheers

Mike
LMWDP No. 237

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Whale

#10: Post by Whale »

Far from me to question you gentlemen but, doesn't generic mean "all and always the same", "without distinction" or at least something to this effect?

Possibly, and I have not been to Italy long enough to make any definite conclusion on this, regionally the espresso bars will have a typical flavour profile to appeal to the regional public.

But surely I have not been completely out of touch with my taste buds when I had a few espressos in Napoli that tasted a certain way and a few more in Positano that tasted different! And there is only a few hundred kilometers (if that) between the two cities. And this doesn't even involve the completely different tasting espressos that I had in Firenze and Sienna.

Agreed that the Italians walk in the bar have the espresso in a few minutes/seconds and walk out. They do not expect to have a taste epiphany every time they have an espresso and the baristas are chain producing the drinks in a manner that may be more efficiency-over-quality. Yes, I agree that the Italian systems works and it has attributes that are both good and bad.

I am very confused here. I have no doubts that everybody is in good faith, but regardless of taste preferences what is meant by generic?
LMWDP #330

Be thankful for the small mercies in life.