Some thoughts on dosing

Beginner and pro baristas share tips and tricks.
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RapidCoffee
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#1: Post by RapidCoffee »

Dose, along with grind and distribution, is one of the seminal elements in puck preparation. There's been active discussion on dosing recently, so perhaps it's time to start a new thread on this important topic.

One school of thought, championed by Ken Fox, believes that a dose of exactly 14g is best for all coffees, all grinders, all (double) baskets, all espresso machines. At the opposite end of the spectrum, we have folks like Chris Tacy, who disclaim the notion of a "traditional" double, spurn any and all general rules, and believe that every coffee, every basket, every grinder, every espresso machine has its own optimal dose.

My views lie somewhere between these extremes. I do not believe that a single fixed dose produces optimal results for all coffees and gear, nor do I disdain the notion of general dosing guidelines. Besides personal experience, several observations have influenced my thoughts:

I'm a big fan of Andy Schecter's brew ratios. The coffee:water proportion is a major contributing factor to the pour, and Andy has given us a simple, effective tool for describing this ratio. Coffee dose alone is not sufficient, especially when you look at lever machines, with their fixed water volume per pull. For example, to brew a traditional double on my Gaggia Factory lever machine, I use a 14g dose. That's because a full stroke of the lever nets ~28g liquid, for a brew ratio of 50%. On pump machines, I stop the pour by color (blonding), but typically strive for a brew ratio in the normale double range.

Puck headspace, as Dan Kehn has noted, is another important factor in determining dose. This is highly dependent on the espresso machine, and how far down the dispersion block extends into the basket. Jim Schulman has proposed other espresso machine considerations, such as the evenness of water delivery to the puck.

Given that all coffees and all machines are different, are there any measurable dose factors that can be used to formulate general principles? I spent some time this morning, carefully weighing the natural dose capacity of each of my dozen+ filter baskets. From top to bottom, left to right:
QuickMill single, Rancilio? single, Gaggia Factory 51mm single, Gaggia Factory 51mm double (2)
Marzocco 57mm double (2), QuickMill double, Spaziale 53mm pod basket, Spaziale 53mm double (2)
ridgeless "14g" Synesso double (2), ridgeless "18g" Synesso double/triple (2), ridged Rancilio? triple (2)
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By natural dose capacity, I mean the amount of coffee that naturally fits in the basket. No tapping, just fill the basket and groom it level. I used the same ground coffee (Cuvee Meritage blend) for each weighing, and did my best to follow exactly the same dosing regimen for each basket.
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Here are the results:
QM single: 12.4g
Rancilio single: 13.6g
GF single: 11.9g
GF double: 14.8g, 15.0g
LM 57mm double: 17.4g, 18.4g*
QM double: 17.1g
Spaz pod: 9.3g
Spaz double: 17.5g, 17.9g
Synesso 14g: 18.6g, 19.0g
Synesso 18g: 21.3g, 21.4g
Rancilio triple: 21.0g, 21.2g

* the only baskets that showed so much variance in capacity

A couple of observations:
Within each basket class (single, double, triple) there is significant variation in capacity. The basket capacity is likely to be of greater significance than the class label. The exact weight will vary a bit with the coffee used, but the relative capacity proportions are independent of anything but the basket size and shape. To achieve a desired brew ratio, you can use the natural basket capacity to estimate the target water volume when e.g. programming an automatic espresso machine.

The so-called "14g" double basket is a fiction, and the "7g" single even more so. To achieve these doses, you must carefully weigh the grinds, or adjust the grinder doser (or timer) to deliver this amount. The coffee grinds will not reach the basket rim, which makes levelling a challenge. Only the 51mm lever double basket approached 14g (really 15g), and none of the singles came close to 7g.

But this is not really an issue, unless you insist on a 14g dose. Unlike some, I have not experienced channeling problems when dosing over 14g. There is plenty of headroom, even at much higher doses. On the 53mm Spaziale S1, the natural basket capacity of 17.5g yields a puck that tamps well below the ridge line:
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I don't see how this could possibly be termed overdosing, and it does not lead to channeling:
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I'd also like to propose a terminology change. The terms "overdosing" and "underdosing" imply you have done something wrong. I prefer "updosing" and "downdosing", which reflects a purposeful attempt to vary the dose, rather than a mistake. "Overdosing" might be reserved for cramming so much coffee in the puck that locking in disturbs the puck integrity and causes channeling... but didn't Paul Bassett win the 2003 WBC in this way? I'm not even sure what "underdosing" is supposed to mean. Perhaps when you can no longer grind fine enough to get proper flow.

So far I've been focussing on the mechanical aspects of puck preparation. Taste is another issue entirely. Like Chris, I do not believe that all coffees are created equal. Some respond better to updosing with a coarser grind, others to downdosing with a finer grind, just as higher or lower brew temps may bring out the best taste profile of certain beans and roasts. But every espresso machine has different brewing characteristics, and baskets have significantly different capacities. So I prefer to use updosing and downdosing relative to a given basket capacity, rather than some ideal 14g standard.

OK, enough for now. Let the fun begin...
John

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GC7
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#2: Post by GC7 »

At the risk of coming off as totally ignorant which in the world of coffee I am close :roll: , I have thought about this a bit and production of espresso reminds me of a complicated form of batch column chromatography. That is something which I am somewhat competent to discuss.

If one assumes that the ground coffee is the general matrix packed into the column (in this case the basket) and attached to the matrix are small solids and a very large number of components of differing solubility in water at different temperatures. Those components that are either eluted or left behind in the matrix (puck) make up the favorable and unfavorable tastes and viscosity (mouthfeel?) that make up the drink. Different coffees will have variable components to extract as well as slightly different matrix components comprising the finished puck perhaps influenced by hardness of the bean and other factors. This too will affect what comes through into the drink under seemingly identical extraction conditions. In fact, this might be where different grinders and the shape and surface of the grinds could affect taste too. The degree of roast obviously greatly contributes to this as well as will the volume of water used in the extraction. More volume more "stuff" coming through but at lower overall concentrations.

By varying the dose you obviously make a highly significant change in the concentration and/or total mass of materials that can and will wind up in the drink and this must have a great influence on the ultimate taste. Obviously anyone with a high school chemistry course will also realize that temperature will affect solubility to a large degree to determine what winds up in the cup as well. Sweet tasting compounds, fruity tastes, bitters and so on will be affected as well and on top of that the threshold effects of taste receptors on the tongue come into play. We could also get into individual genetics of taste receptors but then I would be going too far here.

While I personally have found that 14 gm generally tastes good to me as a starting point I would have to agree with Chris (I think) that things can not be that simple AT LEAST FOR OPTIMAL tastes of different coffees or blends. In a generic sense I believe that 14 gm can probably get you in the ballpark of good drinks nearly every time, however, from a scientist's point of view that is not necessarily optimizing the potential of a given coffee sample.

I hope that makes sense but if not then feel free to "roast me".

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shadowfax

#3: Post by shadowfax »

John,

Thanks for bringing this up and relating some initial work on the topic. Your post is well-informed and characteristically balanced and rational. In connection with the recent discussion of Cuvée Coffeee's Meritage Blend, I discussed a bit about some of the ideas about updosing that I've read here. I hope he won't mind being quoted here:
Mike McKim wrote:I have heard some of the negative noise about updosing, but I guess I don't get it. If up dosing makes it harder, then shouldn't you focus on your barista skills? My thought is that if you focus on your barista skills, your options for coffees are much greater...both in the risk/reward department and also choice of coffees. I do understand that the equipment we use and the "average" home barista equipment might have something to do with it, but trying to mask it with philosophy is just BS. Anyway I could go on about that for hours, but back to sample roasting!
I suppose you could take his comments amiss, but I agree with him wholeheartedly, as a home-barista that's always glad to have pointers on barista skills, especially from guys like Mike, Dan and Clancy. Yesterday I happened to pick up 2 lbs. of their coffee, and I stayed around for about an hour. Dan made me an "honorary taste judge" while Clancy practiced his USBC championship presentation. Dan and Clancy were both working on a Mahlkönig K30 and their tricked out, paddle group Linea--Actually, if I recall correctly, Dan was also prepping baskets out of a Super Jolly. With their heavy 20g doses, I was not tasting any evidence of side channeling, and I don't believe they were even taking advantage of the preinfusion on the groups.

At home, my adjustment to a new brew group and total lack of preinfusion on my new old Elektra has been eye-opening. I've enjoyed 13.5 gram shots and 17 gram shots (in LM ridgeless double), and many in between. I see more evidence of channeling on the Elektra than I did on Vetrano at all doses I've tried; frankly, I attribute this to my newness to the machine, and ultimately the increased difficulty associated with an utter lack of preinfusion on the Elektra, which Ken discussed (in the context of the Cimbali Jr.) in another thread this morning. That being said, Dave Stephens has a wealth of experience with the same machine as me, using a wide variety of grinders which includes the one I am using, and He's not complaining about the issues that I've been having during the first week of ownership.

So, I come full circle to what Mike said. At the end of the day, well-practiced, consistent skills are what you need, and what most home baristas who're having problems with their coffee are lacking. Issues of "optimal" dosing ultimately boil down to a matter of taste, and I really don't think there's any arguing that one can make a huge variety of doses work, and work exceptionally, given the proper skills (which include selecting the right coffee for the dose, or more accurately the other way around). And in the end, it seems best to develop the skills that keep your options most open, or at least the skill that lets you properly prepare the type of shots you prefer.

Like Mike, I think most of us could go on all day about this seminal topic, and since most of us probably don't have sample roasting to get to, I suspect we'll all have a lot more to say on it. :mrgreen: I know I have plenty more to say, but I think I'll have to leave it at this for now...
Nicholas Lundgaard

tomax

#4: Post by tomax »

Neat scale. Where does one purchase such a thing?

Ken Fox

#5: Post by Ken Fox »

RapidCoffee wrote:
One school of thought, championed by Ken Fox, believes that a dose of exactly 14g is best for all coffees, all grinders, all (double) baskets, all espresso machines.
I'm not going to take the bait and try to defend a position I haven't taken.

To rehash, as briefly as I can, there are three aspects to this.

(1) Dose at which virtually all espresso machines will function in a straightforward manner without the need for "fancy stuff" or complex basket preparation. That dose is certainly "on the low end," because you simply can't put 20g of coffee into the basket of any machine, push the PF up on the grinder's built in tamper, and expect to pull a decent shot. If you own an espresso machine that can do this, please point out the error I've made by not considering your machine :mrgreen: On the other hand you can put 12 or 14 grams of coffee into the basket of most decent espresso machines, do almost nothing to it, and expect to pull a technically decent, unchanneled shot. This is not surprising, as these machines (generally) come from Italy, and this is how they do things in Italy.

(2) Dose of a given coffee that produces a shot that pleases you. Without a doubt that depends on who "you" is, & what his or her personal taste is. There is no doubt that the well known "marquee" blends are generally designed to be dosed on the "heavy" side; when dosed lightly, they are completely uninteresting.

(3) It is possible to simply not like espresso produced from an 18 or 23g dose, finding it "too much of a good thing," or conversely to find any and all shots made from ~14g to be thin and uninteresting. Whether one habitually puts their espresso into milk, or drinks it straight, is going to be a big factor in this.

ken
What, me worry?

Alfred E. Neuman, 1955

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Martin

#6: Post by Martin »

An observation I've been "saving" for the Dalla Corte thread on the Bench, but seems to fit here: Both the DC and La Spaziale offer a choice of dispersion blocks--relatively thinner or thicker. I've been experimenting with the DC Mini, and it's clear that the "proper" dose is not entirely dependent on the basket size (I've done doubles and triples.) To state the obvious, a thinner block allows a fuller (higher pack) basket.

Any comment about quality rests on empirical cuppings that I have no business reporting. However, I've settled on the thinner disperser because a) I prefer the shots and b) the thinner is much easier to clean out around the pf lock.

(I like Ken's work, but can we really trust someone who suggests that more is not better? :D)

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shadowfax

#7: Post by shadowfax »

Ken Fox wrote:(1) Dose at which virtually all espresso machines will function in a straightforward manner without the need for "fancy stuff" or complex basket preparation. That dose is certainly "on the low end," because you simply can't put 20g of coffee into the basket of any machine, push the PF up on the grinder's built in tamper, and expect to pull a decent shot. If you own an espresso machine that can do this, please point out the error I've made by not considering your machine :mrgreen: On the other hand you can put 12 or 14 grams of coffee into the basket of most decent espresso machines, do almost nothing to it, and expect to pull a technically decent, unchanneled shot. This is not surprising, as these machines (generally) come from Italy, and this is how they do things in Italy.
Are you laying down stock baskets as a requirement to this, or are you claiming that you don't know of a machine you can do this with using a large 18/21 gram Synesso/LM basket?
Nicholas Lundgaard

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malachi

#8: Post by malachi »

Ken Fox wrote:... because you simply can't put 20g of coffee into the basket of any machine, push the PF up on the grinder's built in tamper, and expect to pull a decent shot. If you own an espresso machine that can do this, please point out the error I've made by not considering your machine :mrgreen:
LM Linea (OEM ridged double basket)
LM FB80 (OEM ridged double basket)
LM GB/5 (OEM ridged double basket)
LM GS3 (OEM ridged double basket)
Mistral Series 1 (LM ridged double basket)
Mistral Series 2 (LM ridged double basket)
Synesso (OEM double basket)
"modifed" Grimac Mia (LM ridged double basket)

Those are the ones I've had personal experience with (ie where I've dosed at 20g in a double basket and had excellent results). Given that this leaves only three machines out of my experience (Bricoletta, unmodified Mia and Astra) and that two of those (the Bricc and the Mia) worked fine at 19g - you can see why I continue to have problems with your claims at universality.
"Taste is the only morality." -- John Ruskin

Ken Fox

#9: Post by Ken Fox » replying to malachi »

In this situation, is it your standard procedure to dose the coffee into the basket, to tamp perfunctorily in 3 seconds, lock, load, and pull the shot?

ken
What, me worry?

Alfred E. Neuman, 1955

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RapidCoffee
Team HB

#10: Post by RapidCoffee »

Ken Fox wrote:I'm not going to take the bait and try to defend a position I haven't taken.
Please forgive me if I've misinterpreted your many posts on this subject, starting with the classic Basket Overdosing thread. Just trying to give credit where due. :wink:
Ken Fox wrote: (1) Dose at which virtually all espresso machines will function in a straightforward manner without the need for "fancy stuff" or complex basket preparation. That dose is certainly "on the low end," because you simply can't put 20g of coffee into the basket of any machine, push the PF up on the grinder's built in tamper, and expect to pull a decent shot.
My grinder doesn't have a built-in tamper, and if it did, I'd remove it. Just because this approach is the norm in busy Italian commercial establishments, does not make it optimal or even appropriate for the home barista.

It is possible that your experience is colored by Cimbali HX espresso machines, which are atypical of home equipment - and apparently unforgiving of sloppy technique. From Dan's review of the La Cimbali Junior DT1:
I partially blame my lazy habits acquired from years of using prosumer equipment, especially E61s, which are more forgiving of imperfect technique (see Espresso Machines 101 to learn more about the E61 group design). To reach Junior's potential, I needed to raise my barista skills to the next level.
So there's an alternate approach, suggested by both Dan and Mike McKee (quote in post above). Rather than advocating 12-14g doses, improve your barista skills so that you can manipulate dose effectively, without fear of channeling. That gives you another parameter to manipulate when trying to extract the most out of a coffee.
John