We're passionate about single-serve espresso grinders. Our review of the Niche Zero was accordingly positive. However, the Niche – and not just since Brexit – eats a large €800 hole in your wallet. We were hoping for similar performance for less money. And that's a heads-up. The G-Iota, which is also sold in many places as the DF64, fills exactly this gap. The DF64 costs half as much as the Niche Zero, but its performance is no slouch.
The current review of the DF64 Generation 2.
In our review, we explore the grinder in all its facets, offer a few tips, and even offer a preliminary comparison with the 23 other espresso grinders we're currently testing. Here's a comparison with grinders in the same price range.
In the meantime, we've published an upgrade video for the G-Iota . We've tried a few things. Among other things, we installed SSP multipurpose burrs, which do a really good job. This makes the DF64 even better.
For Austria and Germany, Bohnendealer* is the importer of G-Iota. Unfortunately, there is no official importer in Switzerland.
Single portions or single dosing – what is that?
Espresso grinders are currently experiencing their second evolution, which has now also arrived in the home market. The first evolution was the step from the "storage container" or "dispenser" to the direct grinder or "grind on demand." Instead of pre-grinding large quantities of coffee and storing them in the dispenser, the coffee was ground directly into the portafilter. The result was a first step toward more freshness and less oxidized coffee.
Today, we're undergoing the second evolution, with the move to single-serve grinders. A large portion of the coffee still sits in the bean hopper, exposed to oxygen and light. The single-serve or single-dosing principle is permeating the market, and it works like this: a home barista weighs the desired amount of coffee, places it in the receiving area at the top, and grinds it directly into the portafilter.
This makes it possible to switch between coffees. For guest A, a decaf can simply be brewed, while guest B prefers a fruity espresso. The coffee stays fresh longer because it's stored in the perfect container. For the home barista, weighing the coffee reveals the connection between the brewing ratio and opens up the possibility of experimenting with recipes.
This is what a single-portion grinder must be able to do:
The mill should have no dead space and spit out all the ground material.
The brewing recipe must be easy to adjust and the grind should produce the same particle distribution even after adjustment, when returning to the same marking areas.
In short, consistency and precision are important!
The bellows of the DF64 ensures that the mill has no dead space.
DF64 as a single dosing grinder
The DF64 fulfills the criteria required for a good single-serve grinder very well. It uses a few tools, such as the bellows, but ultimately, the grinder achieves its goal.
If the DF64 is used without the bellows, it has a dead space of 1.5 grams of coffee. While this is a good result compared to many conventional grinders, it is not acceptable for a single-serve grinder. By using the bellows, the dead space can be reduced to almost 0 grams. We recommend that after grinding the main amount of coffee, you remove any remaining coffee grounds from the area behind the flapper with a few blows of the bellows. Caution: this can result in a powerful blow, which also causes some coffee grounds to scatter on the table. However, we have generally been able to avoid this by using gentle blows. This reduces the residue in the grinder ( dead space or grind retention ), and the 18 grams of coffee added, for example, are consistently ground out.
The grinder also impressed us with its precision. We were able to easily adjust the grind and return to the same setting. The grinder does lack a clear grind indicator. Creative minds have developed markers for 3D printing that work well and can be ordered from portals like Etsy *.
A corresponding update could further improve the grinder or make it easier to use. However, we had no problems setting the grinder back to the same grind setting. In fact, the grinder was more precise when setting and resetting than many other grinders in our test series.
We can therefore attest to the DF64 or G-Iota's ability to deliver everything that makes a good single-dosing espresso grinder!
Espresso performance of the DF64
We enjoyed the espressos from the DF64. They were well-balanced, and different accents were easily brought out. The grinder's particle distribution was solidly average.
Espresso data (T4):
- X50: 318.30 microns
- Fine peak: 20.78%
- Main peak: 247.58 microns
Operating the DF64/G-Iota
We've already covered the operation of the DF64 in the chapter on single-serving capability. Generally, the grinder can be adjusted precisely and easily. The large grinding adjustment wheel rotates very smoothly and allows for continuous adjustment. The large diameter has a slow gear ratio for effective adjustment of the grinding level. This is very positive, in contrast to grinders like the Eureka Specialità , where the small adjustment wheel often overshoots the setting.
The grinder doesn't have any other settings. There's an on/off button. That's it.
Aligning the espresso grinder is not part of the traditional "adjustment" and operating procedures. Some users report that their DF64 was delivered with burrs that were not perfectly aligned. This results in a less precise particle distribution in the ground coffee and also causes the burrs to become dull more quickly. The position of the burrs can be checked and adjusted independently. We will be shooting a video on this. However, there are already several instructions online under the keyword "Grinder Alignment." In our DF64 model, the burrs were perfectly aligned.
When using the bellows, we recommend careful and controlled pressure to ensure the grinding level is not altered.
Side view of the G-Iota with transparent dosing cup that fits directly onto the portafilter.
Size, weight and appearance
Elegant, slim, and heavy—that's how the G-Iota compares to our Decent Espresso . It's available in various colors. We purchased and tested a black and a white model (like all grinders, we also purchased these grinders ourselves for testing purposes). The grinder is one of the heavier grinders in the price range up to €500. Weighing in at 13 kilograms, the grinder is very sturdy and solid. 30 mm high, 130 mm wide, and 225 mm deep create a harmonious look.
The grinder comes with a transparent dosing cup. The dosing cup fits snugly into the portafilter. Our cup developed a small crack when I tapped it out. Benjamin and Michel disagreed on the cup's assessment. While Michel would replace it with a metal one, Benjamin appreciated the transparent design. The transparency is particularly useful for learning and training purposes, as it makes it easy to see how the coffee grounds are distributed in the portafilter.
Not only does the dosing cup fit into the mount, but so do all standard portafilters from companies like Rocket, La Marzocco, and Slayer. Portafilters with larger side ridges tend to wear out the rubber seals. However, these can be easily replaced.
Conclusion on the DF64 - G-Iota
The G-Iota is a truly excellent grinder, impressing in almost all categories in our test. Only in terms of speed is it one of the slower grinders, with only 19.1 grams of output in 10 seconds.
The grinder's noise level is mid-range at 83.2 decibels. It's easy to operate and very precise. The bellows reduce dead space to zero. This makes the grinder excellent for more than just single-dosage grinding.
In terms of value for money, the G-Iota impresses with a purchase price of around €400. As you can see from our video, we're very impressed with the DF64. A truly excellent espresso grinder and a very interesting choice as a single-serve grinder.
And that's not all: if you want to further improve your grinder, you can achieve even better grinding results by using the 64-tooth SSP burr. We'll provide you with the results and video below to let you know whether this is necessary and whether we can tell the difference in a blind tasting. A direct comparison with Niche Zero and Eureka Single Dose is also planned.
Upgrade video for the DF64 G-Iota
► SSP Red Speed Burrs at Bohnendealer *
► G-Iota grind indicator on Etsy *
► Beveled Improved Dosing Cup Holder for DF64, G-IOTA on Etsy *
► G-Iota Dosing Cup Holder 51 mm on Etsy *
*This is a commission link. If you order through this link, it won't cost you any extra. However, we receive a small commission. This helps us purchase additional test materials and publish new tests. Thanks in advance! We also link to a shop we know well and know to provide good service.
