Question on dosing quantity versus grind

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SinkShot

#1: Post by SinkShot »

Hi, I am very new to this forum. I have digested just about all the barista tips as I could on this and other sites, but I still could not find a discussion on the trade-offs of dosing quantity versus grind.

The general ("golden") rule is to obtain about 45ml (1.5oz) for espresso in approximately 25 seconds using a tamp pressure of 30 pounds. And, this seems to be for either a single shot or a short double (ristretto). I am interested in the trade-offs between the quantity of coffee used versus the fineness of the grind, when pulling a short double. Technically, 14g of coffee should be used for a double, but almost everyone here seems to be using 16-20+ grams of coffee, and even using triple baskets. I know many say they only volume dose and don't care, but there are quite a few people who actually weigh their beans to get this larger amount of coffee.

In any case, one can achieve the 45ml shot in 25 seconds using 14g of coffee at grind "x", or achieve the same 45ml volume of coffee using something like 17g of coffee at grind "y". And, of course there is probably a profile of bean weight/volume versus grind for a given coffee (of course at various temperatures and pressures as well, but for this discussion, we assume these are already fixed).

So, I don't exactly understand why more bean weight/volume is being used by so many people. Does more coffee really improve the quality of the shot? And if so, how much is enough? (e.g., a quadruple basket?) Why don't people seem to fix the weight of doubles to the "standard" 14g?

Thanks.

Ken Fox

#2: Post by Ken Fox » replying to SinkShot »

The thing is that you are getting off into an area of "personal preference" that is not the same thing as simple barista skills. In order to develop simple competent barista skills you need to keep everything more or less constant and only manipulate 1 variable. What this would mean is that you would have a machine with say, standard single and double baskets for your machine. You would learn how to dose each of these baskets to produce an appropriate volume for each basket for the drink you want to make. For example, you would try to produce about 1.5 oz from the single and 3.0 oz. for the double, to make standard "North American Length" singles and doubles. These should take about 25, maybe 30 seconds to produce. If you are trying to make ristrettos, you would be trying to make about 0.75 oz. from the single and 1.5 oz. from the double. The ristrettos would take longer to make, maybe 35 or perhaps even 40 seconds. Since the shots take longer to produce and are of smaller volumes, the grind must be finer in order to accomplish this. Dosing in the baskets should be approximately the same. In order to keep things simple you would perhaps want to use a straight edge to sweep off the top of the PF, ensuring a constant volume.

Once you become competent at producing these sorts of shots, and what you have to do to accomplish this becomes reflexive, then you can tinker around the edges and play with how much coffee you put in the basket and other basket sizes (such as triples). The drink volumes I've given are approximate and many here (myself included) make smaller drinks than even the ristretto volumes given above, and as you note we often do it with more coffee in the basket, which is to say that we "updose." If you updose then the grind will by necessity have to be a little coarser to produce the same volume over a set period of time.

But we didn't just start out making 1.25 oz. doubles from 18g of coffee after a week spent with our espresso machines and grinders. Whatever it is that we do, if we have been doing it for a while, evolved over a period of time when we tried out a whole bunch of ways of doing this and then we settled on what worked best, for us. In all cases this would have been a personal choice based on personal experience and taste.

You can't do any of this stuff competently until you can reliably make the standard drinks while alternating only the grind to deal with such things as changes in humidity, age of the coffee, type of the coffee, etc., the things that crop up every day and several times a day on some days, that make consistent espresso making a challenge to even those who are experienced in trying to make it.

No one here can tell you what sort of tinkering around the edges of shotmaking is going to make the sort of shot that you prefer. Once you get the basic skills down pat, which will take practice, practice, practice, then you can discover for yourself by trial and error how you like your espresso made. Using more coffee does make a "richer" shot, but then maybe it is "too" rich for your taste. I played around with triple baskets for a couple of weeks when I finally had a bottomless PF that could take a triple, but after two weeks of experimentation I decided that triple baskets made coffee too rich for my own taste; I no longer use them. But for you they might be exactly what you are seeking. And to be honest, I might change my mind on triples next week, I just don't know.

ken
What, me worry?

Alfred E. Neuman, 1955

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another_jim
Team HB

#3: Post by another_jim »

This is an excellent question.

There are two hidden variables here:
1. the concentration of coffee to water
2. the amount of coffee extracted from the puck

on 1: If you make a 45 mL espresso from, say 12 grams of ground coffee it could be half as concentrated as the one made from say 24 grams of ground coffee. Quite simply, the higher dose can make the coffee stronger.

However, this is not always the case; and this brings us to 2, the more interesting "hidden variable" in this story: Suppose on the 12 gram shot, the spent puck, after being dried, weighs 8 grams, and suppose the 24 gram puck, after drying, weighs 20 grams. Then four grams worth of coffee went into the cup from each puck, and the coffees are equally strong. Will they taste the same?

They won't. When brewing coffee, one is aiming for an extraction of 20%. By that standard, the 12 gram puck was overextracted by 13%, while the 24 gram puck was underextracted by 3.3% What does overextraction taste like? Like instant coffee (instant coffee is produced by a several day long brewing process that dissolves around 50% of the ground coffee). What does underextraction taste like? Like toddy coffee (cold brewed coffee), mild and sweetish, lacking in aroma and flavor.

If you look at the numbers and the description of the flavors you begin to see why people favor overdosing. The bigger the puck, the less a fixed weight of over or underextraction deviates from the ideal percentage (the 12 gram puck was 12% over, while the 24 gram was only 3.3% under). Moreover, overdosed shots tend to err on the side of underextracted, which certainly tastes better than the overextracted variety (unless you prefer instant coffee to sweet and inoffensive).

The best guide I know to getting a proper extraction is to watch the flow of the espresso. Stop the shot when it begins to look watery and transparent, no matter what the time or volume. Also if you choke a shot, that is, if the coffee takes an unusually long time to appear, let the first few drops go into the driptray -- these will be overextracted from the overly long infusion.

However, please don't think this answer is even close to authoritative. There are no good studies on how dosing, grind, flow color and shot time variations impact the extraction; and nobody is even close to figuring out how fast or slowly each of the hundreds flavor chemicals in coffee extract. What I'm saying is based mostly on many experienced people's long but unverified tasting experience combined with their conjectures. It's informal know how, but not yet science.
Jim Schulman

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HB
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#4: Post by HB »

SinkShot wrote:So, I don't exactly understand why more bean weight/volume is being used by so many people. Does more coffee really improve the quality of the shot? And if so, how much is enough? (e.g., a quadruple basket?) Why don't people seem to fix the weight of doubles to the "standard" 14g?
As Jim said, a very good question!

Speaking in general terms, when first learning about espresso machine X, I pay careful attention to the puck-to-dispersion screen clearance. For most machines, a few millimeters of clearance (between the thickness of a dime and nickel) allow enough room for water to spread out evenly across the puck's surface. As the coffee expands, the puck's surface presses firmly against the dispersion screen, reducing the chances of outer edge channeling. For espresso machines that have very fast pressure ramps, I experiment with downdosing to increase the dwell time and enhance the evenness of the water dispersion (e.g., the Cimbali Junior and Elektra A3 responded well to strictly standard dosing of 14-15 grams). Sometimes it helps, sometimes it doesn't; it depends on the particular espresso machine.

As Jim said, the extra coffee does offer a larger margin of error too, but only up to a point. For example on my machine, 17-18 grams is the extraction "sweet spot" for evenness. Above 19 grams, the margin of error for distribution faults and grind setting becomes smaller, even for a triple basket (related article). In other words, "more is better" isn't always true. As Ken said, it's very difficult to offer specific suggestions unless we have the same equipment, coffees, and similar taste profile preferences.

Espresso making at home involves constant tinkering around the edges, but that's part of what keeps me interested. Recently Karl (Microcasa a Leva) and Jim (Semiautomatica) have extolled the virtues of single baskets. I never would have considered the possibility were it not for them. Now I plan to dust off the singles... once I find one and a tamper that fits. ;-)

Image
Bucking the trend (from archived polls)
Dan Kehn

SinkShot

#5: Post by SinkShot »

What a great forum! These are excellent, well thought out replies to my query.

So, based on HB and Ken's reply, I figured OK what the heck, I will just try some experimentation. I am proficient with my grinder to the point of being able to consistently bang out 45ml volumes in 25 seconds, producing perfect pucks, neither scorched nor soggy. First, down-dosing led to horrible results, and leaving soggy pucks. So, I started to updose the amount of coffee beans and play with the grind. What I found was that when the grind becomes too fine, the taste becomes just too bitter, at least for me, regardless of coffee bean quantity (even with a start dump). However, when I go from 14 up to 18 grams, and use a harder tamp, the coffee taste is much better (to my liking), but only when I grind to keep the extraction time down to about 27-28 seconds (ie, much coarser than Ken's recommendation for a 35-40 second flow).

Jim's post really got me going though. Now, I can't even look at my pucks without thinking how much coffee I have actually extracted. The idea of drying and weighing the pucks is so simple, that I am now saving my pucks to determine my extraction points. This will be interesting to see, but will take some time to build up enough data over time. This suggestion really helped me, as I was looking for a more quantitative method for understanding this. Thanks Jim!

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another_jim
Team HB

#6: Post by another_jim »

SinkShot wrote:
Jim's post really got me going though. Now, I can't even look at my pucks without thinking how much coffee I have actually extracted. The idea of drying and weighing the pucks is so simple, that I am now saving my pucks to determine my extraction points. This will be interesting to see, but will take some time to build up enough data over time. This suggestion really helped me, as I was looking for a more quantitative method for understanding this. Thanks Jim!
Thank you!! This has been one of those "someone should do it; but not me" experiments.
Jim Schulman

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cannonfodder
Team HB

#7: Post by cannonfodder »

HB wrote:For most machines, a few millimeters of clearance (between the thickness of a dime and nickel) allow enough room for water to spread out evenly across the puck's surface. As the coffee expands, the puck's surface presses firmly against the dispersion screen, reducing the chances of outer edge channeling.
I find that my best shots leave a dry puck surface with a slight imprint of the dispersion screen on the puck face. Once again, that is on my machine with my dose with my technique. Your tests may deliver a different personal preference.
Image

The tamper piston also plays a large part in the extraction (IMHO). Having had a week with the Tamper Road Show, I was able to try dozens of different dose to piston to machine combinations with some eye opening results. However you must learn to walk before you run. It took me a good year to get to the point I felt confident in my base skills before I started to experiment.
Dave Stephens

Shutterman

#8: Post by Shutterman »

I started to post this as a separate thread, but this seems to fit well here. I hope the OP doesn't mind me "piggy-backing" onto his question.

As one who's in their first year of "apprenticeship" also, dosing is one area I too have been struggling with. I've managed to become fairly consistent in my other techniques to the point where I'm at least now getting pucks that look similar to the one pictured above. I've also managed to get flows out of my bottomless portafilter that look similar to some of the espresso "porn" shots I've seen here and elsewhere.

However dosing and, frankly, when to end the shot, have left me perplexed. I'm using a double basket bottomless portafilter with my La Spaziale S1. I use a spare double basket to scoop out the beans and then grind for one double shot at a time. I generally fill the basket to the rim with beans as a rudimentary way to "volume" dose and, more importantly, to teach myself consistency in my routine. I then grind and use the Stockfleths method for distribution.

I'm usually getting roughly 1.75 oz in about 25 to 30 seconds. The thing is, I don't know if I'm artificially cutting my shots off too early. If my pour reaches the top of my 2oz shot glass, or if I run longer than 34 seconds or so, I end the shot.

I realize one is supposed to be watching for "thin, watery blonding", but to be honest, I'm not sure if what I'm seeing is often the natural point at which the shot turns from a deep brown to a lighter color. It often changes color around the 15 second mark or so and, yes, on some pours I can see the stream get awful thin prior to my cutting it off...but I don't usually notice a great difference in color. This makes me wonder if I sometimes have cut the shot off too early.

If I try to put more coffee into the basket via some extra compression prior to doing the Stockfleths move, shots are no longer consistent and in most cases the taste seems to suffer. But at this stage of my apprenticeship, I don't know what variables to adjust.

While my shots will taste fine, I often wonder if I'm not getting all that the coffee is able to offer. I think my palate has started to become a tiny bit educated, because I can perceive the range of sour to bitter as I adjust the temperature. However, I'm still left wondering if I've gotten all I could from my shot as I'm not getting the flavor notes that some will mention for a given coffee...even when I've used a coffee that's supposed to have a particularly overwhelming note. Could be that my palate just needs further refining, or it could be my skills that need further development...I just am unsure.

Bottom line to all this is...will my current method for dosing eventually lead down the right road with enough practice, or do I need to completely alter what I'm doing? And...am I completely missing the boat as far as to when to cut off the shot?


Thanks,

Dean

P.S. Oh yes...I feel somewhat sheepish for asking this one other question, but when I see discussion of folks using a scale and doing weight measurements...are they generally weighing the grounds after distribution...before...or is it the weight of the un-ground beans? (I'm referring to the way most commonly mentioned for weight and not this special case of the dried puck...although this is an interesting idea.) I want to train myself to dose by volume, but just for my own knowledge as to how much I'm using, I bought a quality scale so I'll know what ballpark my doses are in.

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another_jim
Team HB

#9: Post by another_jim »

Heather Perry came up with a good trick for "teach yourself at home" blonding. When the shot goes blond, the place where the pour enters the glass leaves a white mark on the crema. When that happens, you've gone just beyond the normal "stop by color" point -- although this is still a good place to stop, especially with lighter roasts.

So take yourself a larger cup, watch the pour, and watch for the white mark on the crema. On your second try, say "now" when you think the time is right -- if you see a white mark form 1 or 2 seconds later, you were right.

If this "correct by color" pour was fast and/or has too much volume, you can updose a bit (for brighter shots) or grind finer (for more bitter). If the pour was slow and/or too little volume, down dose or grind coarser. If it was too fast and too little, get younger coffee; if it was too slow and too much, email me privately about the coffee you're using -- I want it.
Jim Schulman

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HB
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#10: Post by HB »

Shutterman wrote:P.S. Oh yes...I feel somewhat sheepish for asking this one other question, but when I see discussion of folks using a scale and doing weight measurements...are they generally weighing the grounds after distribution...before...or is it the weight of the un-ground beans?
I watched Abe Carmeli's technique at EspressoFest 2006. He had asked me to bring a Macap auto-tamper ("I have my own scale"). He weighed the basket after dosing and leveling, then tamped with the auto-tamper using a small scrap of sheetmetal as the basket's platform across the auto-tamper's portafilter rest. At the time I thought, "Sheesh, Abe has really gone overboard. I gave up on taring the basket weight ages ago. And an auto-tamper. Puh-leez, who can't tamp consistently?" Although I still think he's a wound a little too tight - even for me - one can't argue with results. He was firing on all cylinders at EspressoFest.

To your question: You should do what you're comfortable with. If I want to weight the coffee, I remove the portafilter retainer clip and "drop in" the basket after weighing. It's the most accurate. Weighing the beans and grinding until empty is darn accurate too, but measuring / dumping beans seems to add yet another step. Plus I wonder about grinder variability due to "popcorning". Hmm-m, now who's wound too tight... :oops:
Dan Kehn