Scottie Callaghan Dosing Tools Explained
Originally, I developed these dosing tools for myself, in preparation for competition, it was just to solve a problem or more importantly to help me find a solution. I have found other people to be increasingly interested in them and they are always asking me what are they for or how do they work? Interestingly enough I have also noticed some forums with photos of my dosing tools with an inaccurate explanation on how to use them. So the following includes how to and why on the subject.
You have probably noticed a lot of baristas out there using different devices to sweep with: rulers, barmans blade, butter knife, usually when I see this I dont think the Barista seems to understand the importance of consistent dosing.
I developed the dosing tools to give the user flexibility, control and/or a reference point when dosing with fresh coffee and grinding fresh or to order, for baristas who have found the need to adjust their dose depending on the variables they want to control.
When I was learning how to pour espresso I was taught to learn how to dose consistently and the importance of grind particle distribution at the same time. Doing this then gives you the control to be able to adjust the grind to achieve what has been perceived as a good pour. This learning experience took place for me about five years ago and since then I have grown substantially in my understanding of espresso extraction.
I have discovered through much trial and error that it is, I believe given the drastic nature of coffees varying substances due to its volatility, impossible to say espresso should look like this and be made under these particulars - that would be to put coffee in a box. The question I ask you is what if great French chefs never experimented? Or what if wine (which coffee is so often compared to) was never taken outside of the boundaries in which people thought it should stay in.
My point can be made quite simply if you will undertake a simple experiment, make four espresso with the same coffee, with different dosing but the same extraction speed. So make the first with say 22gms in a double, the second with 18, and the third with 14 and the last with 12. Adjust the grind for each so you achieve the same amount of liquid in the same time frame and taste the results trying to be as objective as you can in the tasting process. If you can, do it blind, with tasters in a separate room to the barista. It is hard to measure between each with speed and adjust the grind as you go. This is why I came up with my dosing tools. What you will find is that somewhere in this experiment there is a dose and grind setting that is best for that coffee on that machine. But use a different coffee on the same machine and you will need to start again to find a dose and grind setting that is best for that coffee. Likewise if you were to take the same coffee and pour an espresso on a different machine you will find that the dose and grind setting will be different on a different machine.
I have discovered that the same experiments can be done with pour speed and volume, lets say you have coffee A and coffee B, coffee A might taste best dosing 14 grams in a double achieving 20 mls in 20 seconds. While coffee B might taste best dosing 22 grams achieving 15 mls in 45 seconds.
I could document substantially more info on this maybe I will one day, these are observations that I have made over the last few years, I have been fortunate enough to have people around who have educated palates to taste what I bring them to taste. They have not seen how I poured the espresso and I do not tell them until after they taste and they have often been surprised at what I tell them they are tasting after they have tasted.
A brief description
A set of my tools comprises of thirty pieces of plastic numbered 1 through 30. Number 1 is flat, number 2 has a very slight curve, number 3 has more of a curve than 2 but still slight, each piece has an increase in the curve from the previous up to number 30 which has quite an exaggerated curve. Most people use this standard set but some baristas have ordered different things like 1 through 35 with .5 increments so 70 pieces in all, the guys at Mecca have numbers 1-40.
Later on, I will go into more depth with my explanation of the tools, but first up I will give an explanation of their most practical application in the broader market. That is the control they give you when grinding fresh (that is assuming you already understand the importance of grinding fresh relating to the coffees accelerated degassing once ground, if you need to understand the importance of this just dial in your grinder, pre grind 50 grams of coffee sit it aside for 20 mins then taste the two side by side, one espresso from coffee ground 20 mins ago and one espresso from coffee ground to order)
In a nutshell, you must be able to dose consistently in order to assess the grind. To dose consistently when grinding to order, create a consistent method for each step as you will see below and then sweep with a designated number, say with #10. So long as each step in your process is consistent and you dont have a technically challenged machine you should be seeing consistency from shot to shot, the main purpose of this is to give you control when adjusting the grind. That is if you are trying to adjust the grind while dosing inconsistently you will have no more luck than a blind man in a dark room because you have no benchmark. Begin with achieving a consistent dose before adjusting the grind.
For dummies and objective consistentsy, in cafes that have a number of people on the machine on any given day, find the best number that suits your machine and achieves a reasonably dry cake. Keep this one next to the grinder and teach/create a consistent dosing method that everyone has to use.
Collapse, Sweep, Tamp
*Ill leave collapsing till last
This is the action of removing some measured amount of coffee from a mound of coffee you have dosed into the filter basket.
It seems a lot of people confuse how hard they tamp with dosing (how much coffee they put into the filter basket) inconsistencies, I do not think how hard you tamp plays as much a part in the extraction as how much coffee is in the basket. I do think you need to tamp firmly but I will say that I think in most cases when people think the extraction is different than the previous because of how hard you have tamped would in 90 percent of the cases have confused this with the dose and in actual fact the extraction is different because they are not in control of their dosing.
My method when I am using my Dosing Tool is to make every move consistent so that when you come to sweeping with your choice of number it will be consistent, i.e. if you were to dose two separate porter filters and on the first collapse once and the second collapse four times and sweep with SCDT #5 both times. Even though you are using the same number both times the latter would have more coffee than the former because of the inconsistent collapsing.
I am not sure who was the first to use the collapsing method, but some baristas choose to use it to achieve consistency in their dosing. This is to say that if you where to dose into your filter basket until there is a mound and sweep with your fingers, a knife, a ruler, my tools, whatever, with no collapsing it is impossible to measure your dosing consistency. This is because of the nature of coffee when it is fresh; it clumps in different amounts, leaves small air pockets. By knocking the bottom of your porter filter/group handle on a solid bench you can eliminate this variable, the coffee will sink into your filter basket and break up any possible inconsistencies, when doing this it is important to remember a few rules.
1. Collapse the same amount of times every time
2.Collapse with the same strength every time, that is dont collapse once softly and then harder.
3.Collapse in between dosing. So if you where to collapse six times all up fill up the basket 1/3 collapse twice then 2/3 collapse twice then full and collapse twice.
4.Dont collapse too many times. 10 times for instance would be overkill, this is time consuming and there is a point when you have collapsed sufficiently to achieve the result you are after. Collapsing too many times also causes uneven grind distribution. On the same token once wouldnt be enough.
5.You need a rock solid surface, something like a strong stainless bench, a block of marble or a grinder like a Mazzer Robur where you can collapse in the forks and on top of the dosing chamber.
My Dosing Process using a Mazzer Robur
Beginning with an empty dosing chamber,
1. Grinder on
2. Pull group handle out of group head
3. Knock coffee out in knock box
4. Clean/wipe out filter basket
5. Grinder off
6. Put group handle on grinder forks
7. Pull dosing chamber lever 4 times
8. Collapse on grinder forks twice
9. Pull dosing chamber lever another four times
10. Collapse on grinder forks twice
11. Pull dosing chamber lever four times
12. Collapse on top of grinder (given you are working on a grinder that has a metal casing for the dosing chamber) four times
A practical application
Lets say you are working with a grinder that has a stepped grind adjustment unlike the Mazzer say a BNZ.
You pour a shot where the grinder is set on #13 for example and the extraction is a little fast.
So you adjust the grinder to #12, which is one step finer, and the shot is a little slow.
Lets say you are working with SC dosing tool #20 and you need to adjust your dose to achieve a good extraction: - in this case you need to put a little less.
So you change from SC dosing tool #20 to #22 which takes a little more out and compensates for the grinder not capable of achieving a grind setting in between #13 and #12 on the grinder collar.
In this instance what the tools do is give you a reference point in adjusting your dose.
Another practical application
If you want to achieve a decent pour with a single basket and a double basket with the same grind you can with my tools.
Simply set the grind for the double,a 16-gram basket for example, and lets say you find SCDT #5 to be the best tool for the double. Now you simply work your way from #30 then #29 and so on with the single basket say 9 grams until you find the number that best suits the single basket. This is a good option for low volume establishments.
Lets say you follow this technique using dosing tool #10, but find you are getting a lot of choking i.e. the pour starts off looking nice, slowly speeds up but towards the end while the colour is still good the pour goes back to dripping. (choking/pulling up) From here, using the same consistent method you can change to #13 (sweeps more out than #10) by doing this you are allowing more room inside the basket for expansion which might stop the choking, if not change to a higher number still all the time adjusting the grind and all the time tasting the difference in the coffee (dont be afraid to spit or you will die of caffeine overdose, or have some serious road rage on the way home)
Varying Extractable flavours method
Providing I keep consistent with each step I am going to end up with a consistent amount of coffee, which gives me control in adjusting the grind. I can then pour an espresso with the coffee I am working with at a few different speeds to asses the flavour and decide whether or not I need to change my dose. This is because some coffees taste better with a courser grind, more coffee in the basket ending up with a harder cake and other coffees taste better with less coffee in the basket a finer grind and softer cake.
This is basically because coffee has over 2000 substances in varying amounts depending on species of tree, farming methods, farm location (environment), processing, packing, date range till roasted, roaster used, roast profile, date range from roast date, packaging etc which results in different amounts of different extractable flavour groups and each of these flavour groups need different levels of water volume, water temp, pump pressure to be dissolved and end up in the cup, of course some of these flavour groups are desirable and others are not.
I will make a quick note here that another varying factor is the coffee machine you are working on as each make and model behaves differently in regards to thermal stability, pump pressure, flow rate, brewing temp etc and so the exact same coffee from the same roast batch extracted at the same time will need to be ground and dosed differently from one machine to the next.
Lets say you are working with a coffee 6 days from the day it is roasted, you are dosing with #5 so achieving a fairly hard cake. The pour is starting off fairly quick but because there is more coffee in the basket the restriction which comes from expansion stops the pour from speeding up too quickly so as to have resistance and hold its colour. For some this is an ideal pour, but with some coffees you will notice an offensive aftertaste despite top grade green beans and cutting edge roasting. Try changing to #15 fine up the grind so the pour starts of slower and speeds up a little quicker and taste it, whether you enjoy this more or less than the previous you should at least notice a substantial difference in flavour. This is because the different grind sizes and dose volume have allowed for different volumes of water to touch different levels of grind particle surfaces and so dissolving different extractable flavours.
So I encourage you if you choose to buy a set of my tools to do experiments like these, one experiment I encourage people to do is take 3kg of a good freshly roasted true specialty coffee. Get alone in a room with a grinder and an espresso machine. Start with #1 and work your way through the whole set to #30. Grinding and dosing different amounts with the control the tools give you and taste the results.
Time to Start Experimenting
So what goes on in my head to come up with such a thing? I guess the best way to answer this is to explain a bit about my experiments over the last six years, they are many and varied but come from a pursuit to understand this strange roasted seed we call coffee. My experiments started six years ago with trying to achieve consistency by using the dosing chambers on a grinder, measured on a volumetric machine with a stopwatch only to endless frustration. So this followed with training myself to grind fresh and sweep with my finger, from here I have experimented with and without a stopwatch, with different tampers, the old up dosing technique, under dosing, with coffee just out of the cooling tray so it hasnt had a chance to begin degassing, with nitrogen, with just vacuum sealing and no nitrogen. Now I could and hopefully will one day go into in more depth all the experiments I have conducted since then involving such things as varying roast profiles with the same single origin, different packaging with these same roasts and tasting on varying date ranges. Experimenting with different dosing techniques. On different machines with different grinders etc and all this while on my own in a room and my equipment at least one day a week every week for the last six years, on top of working as a barista/barista trainer.
So the point of this article is not to go into all that, but to explain that I have come to appreciate how incredibly different every coffee needs to be ground and dosed to get the best out of it. The more you learn about coffee the more you come to understand how varying and inconsistent the path from farm to cup is. And as a result the barista needs to be in control of the most minute details if they are to get the most out of the coffee they are working with, so this is why I developed my tools - to give me and now you control when trying to find the sweet spot with any given coffee on any machine.