Updated for 2021. Hello coffee and espresso lovers, today we’re getting into the nitty-gritty details of all things low-to-zero retention grinders. We’re starting out with what grind retention is and why it’s important and then trailing into the top 7 low retention grinders with some interesting test results, so keep reading.
What is Grind Retention and why is Grind Retention so Important?
Grind retention determines the grinder’s ability to dispense the same (or close to the same) amount of coffee that you put into the grinder. For example, if you add 18 grams of coffee beans to your grinder and it dispenses 18 grams of coffee grounds, then your grinder is a zero retention grinder.
Most of the time grinder won’t dispense the exact amount of coffee that you added—instead of dispensing 18 grams, it might dispense 17.78 grams of coffee. But, that’s still a heck of a lot better than a lot of grinders on the market that retain a lot of your coffee grounds.
If you don’t really care about the specific of grind retention then a zero retention grinder might not be for you, but if you really want our take on one of the key elements of getting good quality and consistent espresso, then here’s our thoughts on the top low retention grinders.
Top Low Retention Grinders
So our competing grinders in order from the lowest price to the most expensive.
We have the ROK manual. It’s an easy to use, hand-powered unit with a grind straight thru design and stepless adjustment.
Next the Baratza Sette 270. It grinds straight through like the ROK, but the motor makes it easier and super fast.
The Forte is similar to the Vario but uses a more powerful motor and has a more robust and durable full metal case.
The Mazzer Mini is an Italian grinder that’s been around for a while. I’ll be using the Electronic A version.
The ECM V-Titan 64 is made in Germany and features titanium coated burrs.
And last up is the Ceado E37S. Like the Mazzer it’s made in Italy. The E37S was updated for 2017 and features the largest burr set of the group at 83mm. It uses Ceado’s steady lock technology and is known for producing very consistent dosing weights.
To test the grinders I first dialed each into a grind size that produced a standard double espresso from an 18-gram coffee dose in twenty to thirty seconds from the first drip. Then I meticulously cleaned the grinders using a variety of tools, including brushes, some pokers, and a vacuum. Although laborious, it was relatively easy to do the cleaning and maintain the grind setting on all but 2 of the grinders.
How To: Basic Espresso Technique - Dialing in Grind Size
The ROK manual grinder was a breeze with its straight-through design and nothing to take apart. Same for the straight-through Sette 270 with an easy to twist out burr assembly. The Vario and the Forte were fairly simple with their top burr that twists out with a custom tool. On the Ceado, it’s just 3 screws and your in with no loss of grind setting.
Cleaning & Reassembling
With the ECM V-Titan and the Mazzer Mini, it was a little more challenging to open them up for cleaning and then reassemble while maintaining the grind setting. To do that, I made note of the grind setting, then found the zero grind setting by operating the grinder and turning the adjustment until the burrs touched. I then noted the angle of rotation made between my dialed in grind and the zero grind setting.
After cleaning and re-assembly I returned the grinders to their zero setting and backed them off by the angle of rotation noted prior to taking them apart. That all sounds a little complex but was actually much easier than it sounds.
With the grinders cleaned and set back to the dialed-in grind size, I weighed out 18 grams of beans accurate to 1/100 of a gram. At times, I was literally splitting beans to nail the 18 grams on the scale. Those beans were then single dosed into a grinder and the grinder was run until no more ground coffee exited the grinder. What came out was then weighed. This process of cleaning, calibrating, grinding and weighing was repeated 3 times on each grinder.
A couple of notes on the procedure. I used Maromas Arabea coffee from the same bag for the tests. When practical, any ground coffee that was easily accessible by a brush in areas like a chute was brushed out and included in final weights. And, if you try these tests at home you may see slightly different results based on variables like coffee type, humidity, static and other factors.
So here are the results showing the average weight dispensed for the three grind cycles done on each grinder. They’re ordered here from best to worst.
Taking top honors was the ROK Manual grinder with an average of 17.68 grams dispensed. The worst performer was the Mazzer Mini which dispensed an average of 14.8 grams, meaning it retained an average of 3.2 grams.
In this group, the Mazzer is a real outlier. Why is that? Well, it’s a design that’s been around for a while. In the Mazzer, there’s a lot of space between the burr and the walls of the grinding chamber and then a relatively long horizontal space between the chamber and where the coffee falls into the delivery cone. An anti-clumping screen helps to hold coffee back as well.
For the other six grinders, based on my testing, it’s fair to consider them all zero retention grinders for practical purposes. Keep in mind that a half gram of old coffee makes up only about three percent of an 18-gram dose. I challenge anyone to pick up a difference in flavor from that three percent in a blind taste test.
Factors to Consider
Now grind retention is just one measure of a grinder’s performance. Other factors include grind quality, dosing accuracy, ease of use, duty cycle, cost and more. For me, the big takeaway here is that with the exception of the Mazzer, you don’t need to grind out and throw away coffee to get a fresh dose from any of these grinders.
If you have any questions about zero retention grinders, be sure to give our experts a call or use the chatbox on our website, we’d be happy to help you out.