The Technician’s Guide to Espresso Grinder Selection: How to Help Inform a Cafe Owner’s Grinder Purchase
/By Chase Lemos
Espresso grinders are an important factor in any coffee setup. The purpose of the following article is to help espresso techs learn what kinds of espresso grinders are appropriate in certain settings. This will elevate the value of a technician to a new or growing cafe.
To start, should your customer have a doser grinder or a doserless grinder?
The purpose of a doser on an espresso grinder is to allow high volume accounts to pre-grind coffee allowing them to make it through a rush without having to stop to grind coffee for each shot. This way, the shop can pump out the maximum amount of drinks and keep the espresso machine running at full capacity.
The tradeoff can be the flavor of the coffee. Pre-grinding the coffee increases the time the surface area of that coffee is exposed to ambient air and oxidizing the now exposed coffee oils. The process of oxidization will take about 20 minutes to become noticeable. The effect is a ‘flattening’ of the coffee flavor.
As long as the cafe is able to use all of the pre-ground coffee before it spoils, a doser grinder can be a real benefit to the cafe. Any left-over coffee after the 20 minute mark should be thrown away in the name of flavor. Failure to do so will result in an espresso shot with a muted flavor profile and very little crema.
The other type of grinder is a doserless or on-demand grinder. The advantage of using an on-demand grinder is low waste and fresh-ground flavor associated with every shot. Especially as modern grinders get faster and quieter, more and more cafes are choosing to go doserless for these reasons.
One grinder, the Quality Espresso Q10 has a unique blend of being both a doser grinder and a doserless grinder. The grinder has a chute that can be programmed (by means of the touchscreen), allowing the barista to choose to:
- Save a dose in the chute to be distributed when the microswitch is depressed and then the grinder grinds another dose and stores it in the chute for the next need – doser
- The grinder does nothing until the barista depresses the microswitch. Once the switch is activated, the grinder grinds and distributes a shot - on demand
- The grinder does nothing until the barista depresses the micro switch. Once the barista presses on the switch, the grinder will grind until the switch is released and distribute the ground coffee.
This grinder is the only one I know of to blur the lines between a doser grinder’s speed and a doserless grinder’s ability to provide fresh ground coffee with every shot. Another advantage is that when in the ‘doser grinder’ setting, the maximum amount of coffee wasted is one dose.
Should you recommend flat burrs or conical burrs?
This can be a tricky question to address. Both types of burr have the ability to produce exceptional coffee.
Flat burrs spin faster causing them to spit out the coffee faster, but they also heat the coffee (and grinder as a whole) faster. This can make them a good fit for a small to medium cafe that needs coffee to grind quickly when they hit the button and doesn’t mind the added noise.
Conical burrs spin slower, causing them to spit out coffee more gently with less heat created. For this reason, conical burr grinders are typically geared for a medium to high volume cafe. When you need to grind ten pounds of espresso in an hour, it takes specialized equipment to be able to keep up with the volume and keep any charred flavor out of the ground coffee - queue the conical burr.
When looking at a cafe and attempting to judge which burr would be preferable, keep in mind that while daily pounds of coffee needed is important, you really need to look at the peak amount of coffee ground in a given hour. Let’s say that a cafe only goes through 6 pounds of coffee a day. They want to purchase a Mazzer Super Jolly but have been told by their roaster that they need to purchase a Mazzer Robur. At first glance, it would appear that 6 pounds of coffee a day is a fine load for a Super Jolly - but upon asking the owner about their morning rush, he informs you that 5 pounds of that load happens between 7am and 7:45am. Well, to help the owner purchase the best piece of equipment for their needs, think about a Super Jolly. 64mm burrs, grinding 5 pounds of coffee in 45 minutes - that is 6.67 pounds of coffee an hour, or .11 pounds of coffee a minute - almost 50 grams of coffee every minute. If the coffee shop is pulling an 18g double shot, that is 3 shots pulled every minute. Can a Super Jolly maintain a rate of 3 shots per minute for an hour? It probably could if it had to, but the grinder will get hot and may not perform up to the cafe’s standards in that situation.
This doesn’t make the Super Jolly a bad grinder, but it does (likely) mean that you should not recommend that the cafe owner purchases a Super Jolly because of their peak load. A Kony or Robur would be better suited for this cafe, even though they will be severely underutilizing it for the majority of the day. If the cafe insists on purchasing the smaller grinder, they can expect to go through a few motors, perhaps some capacitors and a whole lot of burrs. (They would need new Mazzer Original burrs every 133 days. More on this later).
How large should the burrs be?
Flat
- For home use or a small cafe, 50mm flat burrs are just fine. (Serving less than 25 coffees a day). In Mazzers, this is the Mini (58mm burrs).
- For a small to mid-size cafe, 64mm flat burrs should be fine (less than 8 pounds a day spread over the course of the day). In Mazzers, that would be the Super Jolly.
- For a mid to large size cafe you should look in the 83mm range for flat burrs. (8-15 pounds spread over the course of a day with bursts mixed in there). In Mazzers, this would be the Major.
- For a large size cafe, you will need a 100mm+ flat burr. (This would be a cafe in the 15+ pounds per day - per grinder).
Conical
- For a mid-size cafe, 63mm conical burrs are fine. (8-15 pounds of coffee a day with heavy rushes). In Mazzers, this would be a Kony.
- For a Large size cafe, 71mm burrs are fine. (15+ pounds of coffee a day with very heavy rushes).
**I used Mazzer grinders as an example because Mazzer SRL is a well-respected brand in the coffee industry and is one of the widest used coffee grinder manufacturers on the market. The hope is to use a grinder that the most technicians will be able to relate to.**
When should a cafe change burrs?
Short answer – when they are dull. When is that? It will vary from account to account. The coffee used will affect how quickly the burrs will wear. Darker roasts are easier to grind because they are softer but can cause increased clogging in some grinder burrs - lighter roasts are harder to grind because they are denser and have more water retention. The burr installed will have an impact on how quickly the burrs will dull. Burr geometry and burr steel will both be a factor here, look for an article on this in the coming months!
A typical 64mm flat burr will grind around 800 pounds of coffee before it dulls. A typical 83mm flat burr will grind around 1400 pounds of coffee before it dulls. To test burr sharpness, drag the top of your thumb nail over the top of the ‘teeth’ in the direction they cut, if the burr begins to cut into your finger nail, it is sharp. If the burr does not cut into your nail and instead your nail just skids across the ridges in the burr, it is dull.
Stepped vs Stepless
Coffee grinders can be what is known as stepped or they can be stepless. To tell which is which, look at your grind adjustment. Does the grinder have a pin that has to be pulled out or a lever you have to push to adjust the grind? Does the grind click into place when you have set it? If so, you have a stepped grinder. These grinders have preset ‘steps’ that you can use to adjust your grind. The advantage is they don’t move unless you move them - meaning that your grind will stay just where you want it until you decide to change it. The disadvantage is that you can only adjust your grinder in increments. You can set it to point A or point B, but not the space between A and B. You give up some measure of control for reliability. In most modern grinders, the steps are so close together that you may not even be able to tell the difference between A and B and so working about the space in the middle may not be worth your time.
Stepless grinders have infinite adjustability. You can get exactly the particle size that you want because the machine doesn’t stop you. This can be a major boon for the coffee guru who is in search of the perfect cup of espresso. The tradeoff is that the vibrations of the grinder or an accidental bump of the grind adjustment wheel can cause you to lose your perfect setting.
Does this matter to your cafe? Maybe, maybe not. If you are talking to the cafe owner and she is very excited about being able to dial in her espresso to be just perfect, you may want to recommend a stepless grinder so that she can have the control she is looking for. But if you are talking to a cafe owner and she is more concerned with preparing the required number of drinks and as long as the espresso is good, she is happy - you may want to go with a stepped option. Different strokes for different folks!
The cafe decided on a doser grinder, should I get a Manual, Timer or Automatic?
This can be a matter of preference. Manual grinders have a simple on/off switch and the fill the doser when they are turned on and they stop when they are turned off. There aren’t many moving parts and so they have a tendency to run for a long time before needing to be replaced. The cafe owner does need to be aware that they will have to actively monitor the grinder when in use, however, because the grinder will be happy to grind an entire hopper worth of beans without a second thought!
A timer grinder has a knob (generally) that you turn to make the grinder go. You turn it to, say; 45 seconds and the grinder will chug away for 45 seconds and then turn off. The advantage is (since you decided on the dosing model over the doserless) that you can make the grinder go, and turn back to the espresso machine, cash register or any other task because you know the grinder isn’t going to over fill the doser. Then, you have coffee ready and waiting when you come back to click out a dose of coffee.
An automatic doser is a nice feature for the very busy cafe. The doser has a micro switch that you can adjust to maintain a level of coffee (say two inches) in the doser at all times. This means you never have to fiddle with a switch, simply dose your coffee and the grinder will take care of the rest. Just make sure to throw away the first doser full of coffee in the morning because coffee that has been ground all night is sure to taste flat. The problem can arise when the cafe hits a quiet time and isn’t using a doser worth of coffee every 20 minutes because the coffee will taste stale.
By considering all of these factors any technician can provide valuable insight to a cafe owner about one of the core pieces of equipment they will rely on every day. Sometimes cafe owners are hesitant to spend money on an espresso grinder with the capacity to suit their needs. Be patient and try explaining that when you recommend a grinder, you are putting your reputation out there. As such you want to recommend the right tool for the job to ensure their equipment makes their cafe and their coffee live up to all of the expectations of their customers. If they insist on purchasing something that won’t suit their needs, perhaps you can convince them to spread the load across several espresso grinders (maybe a one with light roast and one with dark roast) or maybe, just maybe, they won’t budge and get a grinder that is too small despite your best efforts. In that case, with time, they will see that you were honest with them and that they should have listened to your expert advice which will help your overall relationship with the cafe and help ensure that you are the tech they call when their machine is on the fritz.
