Mahlkönig E64 WS reviewed: Grind by weight with electronic grind size adjustment

Mahlkönig packs the technology of their commercial E65S grinder into a compact housing for home use – including grind-by-weight, electronic grind size adjustment in micron steps, and portafilter recognition, a feature otherwise unseen in this price range. The E64 WS costs 999 EUR, is manufactured in China, and shares the grinding chamber with the well-known Mahlkönig SD64. We purchased the grinder and tested it through several iterations.

The third Mahlkönig E64 WS is now on our test bench. And slowly, the potential of this small grinder is becoming apparent. Model number three is shaping up to be the most interesting entry-level espresso grinder for the home, provided you are willing to invest 1000 euros and the full range of the grinder's features is genuinely interesting to you.

Small note: we tested the grinder both on its own and synchronized with the Mahlkönig Sync Scale. In the future, we will also take a look at the synchronization with the Mahlkönig Xenia.

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Design & Build Quality

The E64 WS weighs almost 6 kg at a height of 39 cm and sits stably on the counter. The housing feels solid, the portafilter rest is high-quality and has been revised compared to the first models. The bean hopper holds 250 g.

What stands out negatively: The buttons feel a bit wobbly, especially compared to what we have seen on other grinders in this price range. And the chute – actually a feature because it is height-adjustable – still sags slightly at the highest setting. Better than on the first models, but not yet perfect.

An important point: The original flapper from the first shipments is no good. Static is immense, coffee sprays in all directions. Mahlkönig has since provided a metal flapper – definitely reorder this from the dealer if you have one of the older versions. Newer shipments come with the revised flapper as standard. With the new flapper, the grinder is in a different league: clean, powdery grinding result, few clumps. Without it, proper work is hardly possible.

Grinder & Technology

The heart of it: 64 mm flat parallel burrs – the same grinding chamber as the Mahlkönig SD64. No RPM control, the motor runs fixed at around 1,950 rpm at idle.

What sets the E64 WS apart from all other grinders in this price range is the electronic grind size adjustment. There is no dial, no ring – everything is controlled internally by a motor, managed via the display. The adjustment is made in microns, and the precision is impressive: A single micron? Hardly a second of difference in grind size.

We recommend calibration or zeroing directly after purchase. In the menu under "Maintenance", you run the burrs together until you hear the chirp, and then set the zero point. Then all E64 WS grinders operate in comparable micron ranges – this makes it possible for us as roasters to provide you with specific grind recommendations that you can use as a starting point. For example, we dialed in our Compadre at 95 microns. You should find the right grind size within +/- 10 microns.

Grind by Weight & Guided Dial-In

The E64 WS is a weighing grinder: Insert the portafilter, the integrated scale tares, and the grinder grinds to the set weight. No fiddling with timers, no fluctuations due to changed grind settings. This is the central advantage over time-controlled grinders and the reason why we believe this category is the future of home espresso. This makes dialing in the right grind size a pleasure.

The portafilter recognition deserves special mention: You can save different portafilters, the grinder recognizes which one is inserted based on the weight and automatically adjusts the recipe. No other grind-by-weight grinder in this price range has this. Convenient if you alternate between single and double baskets.

The guided dial-in is the feature we were most curious about. You enter whether your coffee is light, medium, or dark, set the target recipe and brew time – and the grinder adjusts itself. You tell it how long the shot actually ran, and the grinder corrects its grind setting.

Our result: In two to three brews, we were in the target range for every coffee. This is impressive. Especially clever: The grinder anticipates the retention. It knows that after a grind size change, old coffee with the previous grind size is still in the chamber, and it compensates proactively.

But – and this is important – there are unfortunately (still) software limitations: You cannot set less than 40 g brew weight for a double shot. This is a problem for anyone working with 36 or 38 g. The input amount is also limited to a maximum of 19 g – anyone using a 21 g basket is out of luck. Mahlkönig has announced that this will be fixed via an update. Over-the-air updates are possible, which is the good news.

Grinding Speed & Noise Level

27.3 g in 10 seconds – a medium speed. For 18 g, the grinder takes 7.5 seconds, which is fast and fun in everyday life.

During operation, we measure 85.1 dB(A). That's in the upper mid-range – audible, but not bone-shaking. In context: A vacuum cleaner is around 80 dB, and the E64 WS is just above that. Still acceptable for the morning kitchen, but those sensitive to noise will notice it.

Grinding Temperature & Consistency

After five consecutive grinds (18 g each, 20 seconds pause), we measure an average grinding temperature of 32.52 °C. This is in a good range – no thermal stress, no problem even with several shots in a row.

0.067 g standard deviation across the consistency measurements. This is excellent. The scale works precisely: 18.0 – 18.1 – 18.0 – 18.1 – 18.2 g. For a grind-by-weight grinder, exactly what we expect. This is where the gastro-DNA of the E65S shows.

Retention

The retention is 4.1 g absolute – of which 3.8 g is temporary and only 0.3 g is permanent. The low permanent residue is positive: Barely any coffee permanently sticks in the grinding chamber.

But 3.8 g of temporary retention – that is noticeably high for home use. With an 18 g portion, that is over 20% of the total amount that is one generation older than the freshly ground coffee with every grind. If you pull the first espresso in the morning after the night break, those 3.8 g were ground yesterday. You can taste that.

For comparison: Grinders like the Zuriga or the Acaia Orbit are at 0.5–0.7 g. The Fiorenzato Allground is at about 6 g. The E64 WS is in between – not catastrophic, but no masterpiece either. The retention becomes particularly relevant in interaction with the Grind-by-Sync function: The grinder is supposed to automatically readjust, even after hours of pause. But if there is still almost 4 g of old grind in the chamber that isn't purged in between, the anticipation becomes more complex. The software solves this surprisingly well – but less retention would make it easier for it.

Single-Dosing Performance

The E64 WS is not a single-dosing grinder. It is designed as a hopper grinder with grind-by-weight. The 3.8 g deviation with 18 g input corresponds exactly to the temporary retention – the grinder simply does not output everything that is put in at the top. This is due to the design and not a defect.

Anyone wanting to switch between beans must purge the retention – about 4 g. This is possible, but significantly more cumbersome than with a dedicated single-dosing grinder.

Particle Distribution

We analyze the particle distribution in cooperation with the ZHAW using the Retsch Camsizer X2.

The E64 WS shares the grinding chamber with the Mahlkönig SD64 – but the results differ. The reason: bean load and presumably the flapper. In hopper operation, the weight of the beans pushes the coffee differently through the burrs than in a single-dosing grinder, where only 18 g is added without pressure from above. We also know this effect from the commercial E65S and E80 grinders: If the bean hopper is almost empty, the extraction behavior changes.

For comparison – the SD64 in single-dosing mode reaches a main peak of 209 µm at T4. The E64 WS is significantly broader at 265 µm. The fines content is similarly high at 32%, which provides body and density – but the broader main peak means a less homogeneous extraction.

What does that mean in the cup? The E64 WS plays to its strengths with medium to dark roasts: body-rich, dense, with integrated sweetness. For these coffees, the particle distribution is good. However, anyone looking for maximum clarity and transparency in the super-light specialty range will get a narrower, more homogeneous grinding result with the SD64. For the target group of the E64 WS – a grinder with assistance functions meant to facilitate the entry – this is not very problematic. Most coffees you grind with it will be in the medium roast spectrum. And it delivers there.

Grind Size Replicability

In the adjustment test: Espresso (T4), Ristretto (T5), Lungo (T6), back to Espresso (T7). The grinder was visually reset to the initial marker of T4.

The x50 value deviates between T4 and T7 by about 34 µm (289.8 vs. 256.0 µm). The fines content also shifts from 32% to 35%. That is more than we would have expected from a grinder with electronic micron adjustment. However, we can only substantiate this result with one measurement series. Therefore, we measured again.

In the practical test with fixed extraction time, a more nuanced picture emerges: At 95 microns and 27 seconds, the grinder reliably delivers 44–48 ml in the morning. After adjustment to 50 microns (Ristretto) and return to 95 microns, the result remains stable. Even after a three-hour break without adjustment: 46 ml with the same recipe. Outliers only appear after larger adjustments (103 microns and back to 95) – 53 ml instead of the expected 46. The next shot then levels off again.

Overall, the grinder replicates well, but not as well as one would expect from an electronic grind size adjustment. Occasionally, the micron display shows a different value after switching off and on than before. Occasionally, there are inexplicable deviations. Perhaps that was exactly the case with our particle distribution measurement.

With the current software status, this is a weakness. In everyday life, this means: After larger adjustments, it is worth checking the first shot and readjusting if necessary. With small adjustments in the espresso range, replicability is not a problem.

Software & Operation

To put it bluntly: the software of the E64 WS is not yet finished.

The boot time is about 30 seconds – an eternity if you want your espresso in the morning. The display reacts with noticeable latency. Settings that one has saved in the recipe are occasionally not applied. A grind size is assigned, but the grinder does not move to it. That is frustrating.

The Wi-Fi connection to the optional scale (Mahlkönig Sync Scale, around 200 EUR extra) works, but the setup literally forced us onto a chair: grinder into the Wi-Fi, scale into the Wi-Fi, assign the scale to the grinder, set the mode on the scale. There are Mahlkönig videos on this, and once you have understood it, it works. It is not intuitive.

The scale itself offers several modes. If you already have a scale, the added value is limited. The automatic timing starts at the first drop in the cup, not at the start of brewing. That is why you are forced to stop the time yourself anyway, together with the machine. If connected, the scale automatically transfers this information to the grinder. And in sync mode, it then adjusts itself and compensates for the espresso shot, i.e., adjusts the grind size accordingly.

Mahlkönig can roll out updates over-the-air. Much of what is currently snagging is software – and therefore fixable. But as of today, you are buying a grinder that still needs to mature in some areas.

Tasting

In the cup, the E64 WS delivers what the particle distribution promises: structured, clear espressos with distinct sweetness and beautiful creaminess. The versatility of the 64 mm burrs shows across different roasts – from our Apas Espresso to medium-light specialty roasts to darker blends, we achieved consistently positive results.

Dialing in the espresso goes surprisingly fast with the guided dial-in: Two to three shots, then the recipe is set. That is faster than most of us can manage manually. Those who usually need eight attempts to dial in a new coffee will appreciate this.

Conclusion

The Mahlkönig E64 WS is the most feature-rich grinder we have ever tested – and at the same time, one that is not yet completely finished.

Strengths:

• Electronic grind size adjustment in micron steps: Precision unavailable in this price range otherwise
• Guided dial-in with intelligent algorithm that anticipates retention
• Portafilter recognition with recipe memory
• Excellent dosing consistency (0.067 g SD)
• Particle distribution versatile – light to dark

Weaknesses:

• Software still buggy: Latency, occasionally ignored settings, long boot time
• 4.1 g retention – noticeable for home use, especially with the first shot after pauses
• Software-side restrictions for recipe input (min. 40 g brew weight, max. 19 g coffee grounds)
• Flapper in earlier versions (must be reordered), now comes as standard
• Setup of the Wi-Fi environment cumbersome

For whom? For home baristas who want a weighing grinder and don't feel like adjusting the grind size manually. Especially for beginners who feel insecure during dial-in – here, the grinder really takes work off your hands. And for everyone who finds Mahlkönig's vision of a connected chain of grinder, scale, and espresso machine (Xenia) exciting and wants to get in early.

Not for whom? Anyone who wants single dosing and changes beans daily is better served with the SD64 or other single-dosing grinders. Anyone who expects a grinder that works perfectly mature on the first day may be frustrated. And those who expect perfect workmanship down to the last button for 999 EUR – the buttons show where costs were saved.

Value for money: For 999 EUR, you get gastro-technology in home format: GbW, electronic grind size adjustment, portafilter recognition, OTA updates. No one else offers that in this price range. The question is how much patience you have with software that is still maturing. We are at 85 percent. And would buy the grinder anyway.

This grinder will not be on our table for the last time. We are testing the connection to the Mahlkönig Xenia and seeing what the next updates bring. The potential is there.

If everything Mahlkönig has set out to do here succeeds, then the E64 WS is an almost unbelievably good deal for this price. The offer is: assisted brewing. A grinder that accompanies you to the perfect espresso.

Manufacturers like Maro have done it at the espresso machine level. Mahlkönig is following suit at the grinder level. In its design, a real statement and almost where it could be.

We show how the E64 WS compares directly with other grinders with scales in our Grind-by-Weight comparison with seven models.

Technical Data Overview