Mahlkönig E64 WS in review: Grind by Weight with electronic grind adjustment

Mahlkönig is packing the technology of its E65S gastro grinder into a compact home unit – including Grind by Weight, electronic grind adjustment in micron increments, and a portafilter detection that you won't find in other grinders at this price point. The E64 WS costs 999 EUR, is manufactured in China, and shares its grinding chamber with the well-known Mahlkönig SD64. We purchased the grinder and tested it through multiple iterations.

By now, the third Mahlkönig E64 WS is on our test bench. And slowly, the potential of this small grinder is becoming apparent. Model number three is positioning itself to become the most interesting entry-level espresso grinder for home use. If you're willing to invest 1,000 euros and if the grinder's full feature set really interests you.

A small note: we tested the grinder on its own and synchronized it with the Mahlkönig Sync Scale. In the future, we'll also be looking at synchronization with the Mahlkönig Xenia.

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Design & Workmanship

The E64 WS weighs just under 6 kg at 39 cm in height and stands stably on the counter. The housing feels solid, the portafilter suspension is high-quality and has been redesigned from the first models. The bean hopper holds 250 g.

What's negative: The buttons feel somewhat wobbly, especially compared to what we've seen in other grinders at this price point. And the outlet – actually a feature because it's height-adjustable – still sags slightly at the highest setting. Better than the first models, but not quite perfect.

An important point: The original flapper from the first shipments is worthless. The static is enormous, coffee sprays in all directions. Mahlkönig now supplies a metal flapper as a replacement – be sure to order it from your 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 results, few clumps. Without it, decent operation is barely possible.

Grinding Mechanism & Technology

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

What sets the E64 WS apart from all other grinders at this price point is the electronic grind adjustment. There's no dial, no ring – everything is controlled internally by a motor, managed by the display. Adjustment happens in microns, and the precision is impressive: a single micron? Barely a second difference in grind setting.

We recommend calibrating, or zeroing, right after purchase. In the "Maintenance" menu, you bring the grinding discs together until you hear the grinding point, and you set the zero point. Then all E64 WS units work in comparable micron ranges – which allows us as roasters to give you concrete grind recommendations you can use as a starting point. We set our Compadre to 95 microns, for example. You should find the right grind setting with +/- 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 timer fumbling, no fluctuations from changing grind settings. This is the central advantage over timer-based grinders and the reason we think this category is the future of home espresso. Setting the right grind becomes a pleasure this way.

The portafilter detection deserves special mention: You can save different portafilters; the grinder recognizes which one is inserted by weight and automatically adjusts the recipe. No other Grind-by-Weight grinder at this price point has this. Practical if you sometimes work with a single-shot and sometimes with a double-shot basket.

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

Our result: In two to three brews, we were in the target range for every coffee. That's impressive. Particularly clever: The grinder anticipates the retention. It knows that after a grind adjustment, old coffee from the previous grind setting is still in the chamber, and it corrects proactively.

But – and this is important – there are unfortunately (still) software limitations: You can't set less than 40 g brew weight for a double shot. That's a problem for anyone working with 36 or 38 g. The input amount is also limited to a maximum of 19 g – if you use a 21-basket, you're out of luck. Mahlkönig has announced they'll fix this via an update. Over-the-air updates are possible, which is good news.

Grinding Speed & Noise

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

During operation, we measure 85.1 dB(A). This is the upper-middle range – audible, but not bone-conduction level. For context: a vacuum cleaner is around 80 dB, and the E64 WS is just above that. Still acceptable for the morning kitchen, but if you're noise-sensitive, you'll 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 the good range – no thermal stress, no problem even with multiple brews in succession.

0.067 g standard deviation across consistency measurements. That's 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 temporary and only 0.3 g permanent. The low permanent residue is positive: barely any coffee sticks permanently in the grinding chamber.

But 3.8 g of temporary retention – that's quite noticeable for home use. For an 18 g portion, that's over 20% of the total amount that is one generation older than the freshly ground coffee with each grind. When you pull your first espresso in the morning after the night break, these 3.8 g were ground yesterday. You can taste that.

For comparison: Grinders like the Zuriga or Acaia Orbit are at 0.5–0.7 g. The Fiorenzato Allground is around 6 g. The E64 WS is in between – not catastrophic, but not a highlight either. Retention becomes particularly relevant in conjunction with the Grind-by-Sync function: the grinder is supposed to adjust automatically, even after hours of pause. But if there's still almost 4 g from the old grind setting in the grinding chamber that hasn't been ground out in the meantime, the anticipation becomes more complex. The software solves this surprisingly well – but less retention would make it easier.

Single-Dosing Performance

The E64 WS is not a single-dosing grinder. It's designed as a hopper grinder with Grind by Weight. The 3.8 g deviation at 18 g input is exactly the temporary retention – the grinder simply doesn't output everything that goes in at the top. This is by design and not a fault.

If you want to switch between beans, you need to grind out the retention – around 4 g. That works, but is significantly more cumbersome than a pure single-dosing grinder.

Particle Distribution

We analyze particle distribution in cooperation with 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 probably the flapper. In hopper mode, the weight of the beans forces the ground coffee through the discs differently than in a single-dosing grinder, where only 18 g without pressure from above is fed. We also know this effect from the gastro grinders E65S and E80: when 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 fine fraction is similarly high at 32%, which provides body and density – but the broader main peak means less homogeneous extraction.

What does this mean in the cup? The E64 WS plays to its strengths with medium to dark roasts: body-forward, dense, with integrated sweetness. For these coffees, the particle distribution is good. But if you're looking for maximum clarity and transparency in the very light specialty range, you'll get the narrower, more homogeneous grinding result with the SD64. For the target audience of the E64 WS – a grinder with assistance features designed to ease entry – this is hardly problematic. Most coffees you'll grind with it will fall in the medium roast spectrum. And it delivers there.

Grind Setting Replicability

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

The x50 value deviates around 34 µm between T4 and T7 (289.8 vs. 256.0 µm). The fine fraction also shifts from 32 to 35%. That's more than we'd expect from a grinder with electronic micron adjustment. However, we can only back up this result with one measurement series. So 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 pause with no adjustment: 46 ml with the same recipe. Only with larger adjustments (103 microns and back to 95) do outliers appear – 53 ml instead of the expected 46. The next pull then settles back in.

The grinder replicates overall well, but not as well as you'd expect from electronic grind adjustment. Occasionally, the micron display shows a different value after power-off and power-on than before. Occasionally there are unexplained deviations. Maybe that's exactly what happened during our particle distribution measurement.

This is a weakness at the current software level. In everyday use, it means: After larger adjustments, it's worth checking the first pull and readjusting if needed. For small adjustments in the espresso range, replicability is not a problem.

Software & Operation

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

Boot time is around 30 seconds – an eternity when you want your espresso in the morning. The display responds with noticeable latency. Settings you've stored in a recipe are occasionally not applied. A grind setting is assigned, but the grinder doesn't drive to it. That's frustrating.

The WiFi connection to the optional scale (Mahlkönig Sync Scale, around 200 EUR extra) works, but the setup forced us to a chair, quite literally: grinder to WiFi, scale to WiFi, assign scale to grinder, set mode on the scale. There are Mahlkönig videos for this, and once you understand it, it works. It's not intuitive.

The scale itself offers multiple modes. If you already have a scale, the added value is limited. The automatic time measurement starts with the first drop in the cup, not at the brew start. So you're forced to stop time yourself anyway, along with the machine. The scale transmits this information automatically to the grinder when connected. And in Sync mode, the grinder then adjusts itself and compensates for the espresso pull, adjusting the grind setting accordingly.

Mahlkönig can push updates over the air. Much of what's buggy now is software – and therefore solvable. But as of today, you're buying a grinder that still needs to mature in some places.

Tasting

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

Dialing in espresso is surprisingly quick with the guided dial-in: two to three shots, then the recipe is set. That's faster than most of us manage manually. If you normally need eight attempts to dial in a new coffee, you'll appreciate that.

Conclusion

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

Strengths:

• Electronic grind adjustment in micron increments: precision that doesn't exist elsewhere at this price point
• Guided dial-in with intelligent algorithm that anticipates retention
• Portafilter detection with recipe storage
• Excellent dosing consistency (0.067 g std. dev.)
• Particle distribution versatile for use – light to dark

Weaknesses:

• Software still buggy: latency, occasionally ignored settings, long boot time
• 4.1 g retention – noticeable for home use, especially with first pull after breaks
• Software limitations in recipe input (min. 40 g brew weight, max. 19 g ground coffee)
• Flapper on earlier versions (must be ordered), now comes as standard with new shipments
• WiFi setup cumbersome

For whom? For home baristas who want a weighing grinder and don't want to manually adjust the grind. Especially for beginners who feel unsure about dial-in – here the grinder really takes work off your hands. And for anyone 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? If you want Single Dosing and change beans daily, you're better served with the SD64 or other single-dosing grinders. If you expect a grinder that functions completely polished on day one, you may be frustrated. And if you expect perfect workmanship down to the last button at 999 EUR – the buttons show where corners were cut.

Price-to-Performance: For 999 EUR you get gastro technology in home format: GbW, electronic grind adjustment, portafilter detection, OTA updates. No one else offers that at this price point. The question is how much patience you have with software that's still maturing. We're at 85 percent. And we'd buy the grinder anyway.

This grinder won't be our last encounter. We're 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 reads: assisted brewing. A grinder that guides 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 the design of this grinder, a genuine statement – and already almost where it could be.

Technical Specifications at a Glance