Graef CM800 - Espresso Grinder for Beginners in Test

The Graef CM800 is repeatedly called THE entry-level grinder into the world of espresso. At just under 130 euros/150 francs, it also beats much of what else is floating around on the market in terms of price.

But what can the little grinder do, which is recommended by many forums and comes out quite well to well in test reports?

We tested the Graef CM 800. After the first hours with the grinder, our impression was not good. To be frank: we cursed and were frustrated and the coffee didn't taste good.

When a device scores poorly or partially poorly in one of our tests, the following happens with us:

1. we test even more intensively to substantiate our impression factually.
2. we look for ways to eliminate the weaknesses of a device or give you tips and tricks to still achieve good results with the device.

Our test was first published on January 27, 2020. Two years later, the Graef was on our table again and was tested by us in a comparison with 24 other espresso grinders for home use. Both tests have been incorporated into this report and two videos.

Why we test the way we do and why we test at all?

Before I delve deeper into the grinder, I want to briefly explain why we test coffee machines and grinders at all. The Coffee Makers are a coffee school. We also roast and operate a coffee farm in Nicaragua, as well as two cafés in Basel. This grinder test and all others come directly from our coffee academy.

Our goal is for as many of you as possible to be able to drink good coffee with simple means. We are convinced: if many coffee drinkers drink good coffee, they are also more willing to spend more money on quality coffee beans, and the producer benefits from that. As long as espresso machines, grinders, or water limit (or spoil) the quality of the coffee, good coffee won't be used either.

So when we recommend a machine to you, it's because we believe you can make good coffee with it. And if that requires some tips, we'll provide them. Unlike many test portals, we don't live off you buying the machine through an affiliate link.

If you compare our articles, comparisons, and tests with classical test portals, you'll notice that our tests are significantly more nuanced. We don't gloss anything over so you later buy bad equipment.

Wir have tested the Graef CM800 in good company. On the one hand with the La Marzocco GS3 and on the other hand alongside a Cimbali M100.

Overall Impression Graef CM 800

The greatest strengths of the small Graef CM 800 are price and size. At just 13.5 cm deep, 23 cm wide, and 39 cm high, it fits into any kitchen niche. With its aluminum housing and around 2.6 kg weight, it also looks quite solid.

If you can handle the grinder's adjustment well, you can also make espresso with the Graef CM800! This grinder is a Espressomühle, different from many other grinders in the sub-200 € range. Most grinders from Tschibo, Melitta, Rommelsbacher and co. are filter coffee grinders and cannot be set fine enough! Don't let misleading tests lead you astray here.

Our Conclusion Up Front on the Graef CM 800

• Can you make espresso with the Graef CM 800? Yes, that is possible.
• Is it easy to use? No. Unless you're lucky and the grinding range is reasonably correct, the Graef is very cumbersome to operate.
• Who is this grinder suitable for? Not for sensory demanding coffee drinkers. You should also be able and willing to handle a screwdriver.
• The Graef CM800 is sensory suitable for beginners and technically for advanced users.

Grinding Espresso Fresh with the Graef CM800

Freshly ground coffee is always better than pre-ground. Already within 15 minutes, a large part of the volatile aroma components of the coffee have evaporated. That's why the first step to better coffee is reaching for a grinder that allows grinding by the minute.

In general, there's a distinction between espresso grinders and filter coffee grinders. Espresso grinders allow for finer grinding settings. This is necessary to build resistance in the portafilter of the espresso machine.

If you don't grind fine enough, the brewing water slides through the coffee too quickly. If an espresso is brewed in less than 20 seconds, the coffee is under-extracted. The espresso tastes sour, aggressive, and watery. That's why it's very important when selecting a coffee grinder to ensure the grinder grinds fine enough for espresso.

The Graef CM 800 does exactly that. It grinds fine enough and is therefore also suitable for preparing espresso. It is the cheapest espresso grinder we have tested so far. The espresso tastes much better with the Graef CM 800 than when using pre-ground coffee powder.

But how does the quality of the espresso compare to other espresso grinders?

Can Something This Cheap Taste Delicious?

We put many hours of work into testing the Graef CM800. This was due to the laborious grinding adjustment and because we were not satisfied with the taste result.

First, I tested the grinder. Then barista professional and vice-barista champion Michel Aeschbacher worked with the grinder. We did brew espresso, but none of it really convinced us. To rule out that the taste result was limited by the espresso machine, we worked with a professional espresso machine that costs as much as a compact car (La Marzocco GS3/Cimbali M100). The espresso was our Standard-Kaffee Dreispitz, which we serve in our Coffee Makers café at Basel train station.

On the one hand, the espresso was bitter and at the same time had a higher proportion of aggressive acidity. We brewed the espresso with a classic brewing ratio of 1:2.5. 18 grams of coffee in the portafilter resulted in two espressos of 22.5 grams each with a brewing time of 25 seconds.

To verify the result, we compared the espresso with the same parameters using three other grinders (Sage Smart Grinder Pro, Eureka Mignon Perfetto, Niche Zero) using the triangle method. In the triangle method, 3 cups are compared with each other. Two of these cups are the same in taste and one is different. The different cup is marked invisibly from below for the taster.

The subject's task is to find the different cup each time. In this case, we doubled the test series and as an additional task asked which cup tastes worse.

Across all 6 sets, I found the different cup each time and selected the ones tasting worse as the extractions of the Graef CM 800.

But why does the Graef CM 800 have trouble keeping up taste-wise with the other grinders?

Grinding Consistency as the Reason for Poor Espresso

The suspicion was that the distribution of particle size of the ground coffee is very different. Every coffee grinder has a scatter of particles of various sizes. This is also the case with the Graef CM 800. The question was just how pronounced the number of different sizes is. The better a grinder, the greater the number of particle sizes in the desired range. If there are many fine particles and especially many coarse particles alongside the main peak, they extract differently than the desired particle size.

Je by particle size, it's easier or harder for the brewing water to effectively extract the grounds. Finer particles extract much more easily than coarse particles.

Brewing water has much easier access to small particles to penetrate the coffee bean and extract everything. With coarser particles, the effort is much greater and only minimal extraction is achieved.

So we're talking here at the macro level about under- and over-extraction! It's not about whether an entire coffee cup tastes over- or under-extracted, but how many particles have the same size overall. The fewer particles that have the same size, the more under- and over-extracted coffee particles we have. Under-extracted tastes sour, over-extracted tastes bitter. Haven't we written that today already? Exactly, up above in the taste description of the espresso we brewed with the Graef CM800.

Partikelverteilung of the Graef CM800. The above curve illustrates the particle distribution curve of the Graef CM 800. On the X-axis, the particle size in microns is given, and on the Y-axis, the volume of the corresponding size as a percentage. It's typical for a grinder to have a distributed curve. Usually this manifests itself in two main peaks—a fine one and a coarser one.

Before we go into more detail on the curve, a brief note on our further procedure. At our coffee academy, we don't have the ability to perform particle analysis via image or laser analysis. These devices are incredibly expensive, in the six-figure range. But there's a simpler method: a laboratory sieve. Michel Aeschbacher examined the proportion of the finest and coarsest particles using two micron sieves of 800 and 400 size.

He put 50 grams on the sieves. His result looked like this:

• 19.06 grams – Coarser than 800 microns
• 20.69 grams – Coarser than 400 microns and finer than 800 microns
• 8.28 grams – Finer than 400 microns

The rest got stuck somewhere in the sieve. But the numbers already illustrate the point. The typical espresso peak lies somewhere between 300 and 600 microns. With the Graef, quite a lot that's coarser comes through. Some particles are really as large as sugar crystals. While fine particles in the range of espresso extraction certainly have a role to play—coarse particles are a real problem. Fine particles sit between the larger ones and help build enough resistance.(1) Coarse particles cannot be successfully extracted during the short brewing time of espresso extraction (about 25 seconds) and therefore contribute greatly to an unpleasant under-extraction acidity. In addition, they facilitate channeling because they make a compact coffee bed difficult.

Vorne left coarser than 800, right between 400 and 800, and back finer than 400. Espresso extraction time: 25 seconds, 50 grams.

Grinding Degree Analysis via Laser and Image Capture

After the sieve test, we wanted to have our results verified externally. Coffee expert and roaster Benjamin Schütz helped us with that.(2) Additionally, I spent a day with the company Symphatec and compared various grinders and grinds. This helped me better understand the specific surface area of ground coffee.

On six grinders, I set the espresso so that it would produce exactly 25 seconds with 18 grams of coffee resulting in 50 grams final weight in the cup. At this grinding level, I ground 200 grams of coffee from the following grinders as a sample.

Anfim Pratica as a professional benchmark, Eureka Mignon Perfetto, Macap M2D, Sage Smart Grinder Pro, Sette 270wi, Graef CM800.

The grind analysis produced the following picture:

Vergleich Particle distribution of 6 espresso grinders.
May be used when linking to this article.

In this image, it becomes clear that the Graef CM800 (dark blue) has the lowest peak of all grinders checked. It is also the broadest and, together with the Sette 270wi, shows the greatest proportion of coarse particles.

This visual representation explains quite well what we experienced sensorily with the grinder. The measurements of extractions in the comparison also support the low extraction yield.

Lowest Strength and Extraction Yield of the Graef CM800

With the above-mentioned values, I adjusted the espresso, took grinding samples, and of course also made a comparison of strength and extraction.

Strength is the concentration of dissolved solids and is expressed in TDS% (total dissolved solids). Strength can be measured with a refractometer .

If you know the strength, you can calculate the extraction based on the amount of coffee used and the weighed espresso amount (volume espresso in grams * TDS % / amount of coffee powder used).

I came to the following results.

The Graef CM 800 shows the lowest strength and extraction. This also corresponds to the sensory description I determined in the tasting. The low strength presents itself sensorily the same way: the espresso tastes more watery and less creamy and mouth-filling compared to the other espressos. The lower extraction manifests itself in the already described more pronounced acidity.

Grinder Test 2022 - Graef CM800 Under the Microscope Again

As part of our current espresso grinder test series, we were in the lab again with seven grinding samples of the Graef CM800. The result confirmed our previous measurement. Across the entire field of 24 espresso grinders, the Graef CM800 achieves the third-broadest coarse peak and a correspondingly lower peak. This is an expression of the large scatter and shows how difficult the Graef has with precisely grinding coffee particles.

In another category too, the difficulty in handling the Graef becomes apparent. In principle, the particle distribution curve shown above displays the same grinding setting four times. In effect, the grinding setting differs significantly each time.

The following list reflects the data that led to the graph shown above. In all four key measurements, the numbers jump from reference to reference.

In the context of all other grinds, the following graphic also shows the Graef CM800 falling behind the field of better grinders.

Operation and Grinding Adjustment of the Graef CM800

So far I have intensively described the results of the grinder, but haven't yet addressed the grinding adjustment. This is a very important function because the adjustment of the grinding level can also control the flow time of the espresso. The finer the grind, the greater the resistance to the brewing water and the longer the espresso runs. The coarser the grind, the faster the water shoots through the ground coffee and the faster the espresso is in the cup.

Mahlgradverstellung of the Graef CM800

The Graef CM800 has a grinding adjustment of 0-40. That doesn't mean much at first. The central question is how much the grind can actually be adjusted with it. The outer adjustment is very easy to perform and can be done by any user without difficulty.

However, we had the problem that we couldn't achieve an acceptable result with the 40 settings. Our espresso ran through in less than 12 seconds even at the finest grinding level. This could be because, for example, a Kaffee light roasted coffee or due to the altitude of cultivation has a different density. In any case, the espresso ran way too fast.

The solution is to set the internal adjustment of the grinding discs finer. For this, the grinder must be opened. Then you can remove two small screws from the upper grinding disc insert and adjust it finer or coarser accordingly. Best check out our video for this.

Because otherwise you'll experience what happened to us during the first adjustments. If you don't reinsert the grinding disc insert correctly, the grinder will not only not implement your desired adjustment—it's running on a completely different level (much coarser).

We couldn't figure out the function from the instructions themselves. A YouTube video from Graef itself then made the function clear to us. In our opinion: the whole adjustment of the grinding mechanism is really a no-go. The outer adjustment option is easy to use. But if you don't happen to land exactly in that range, then the screwdriver work begins.

That's really not well solved at all. Other devices, such as the Sage Barista Express , sometimes require adjustment of the grinding mechanism. But there it works without a screwdriver and, above all, the insertion of the cone is self-explanatory.

In any case, our mood after adjusting the grinder wasn't great, and we've really adjusted many grinders. For these reasons, we don't recommend the grinder to anyone new to making espresso. The frustration potential here is, in our view, too great. We opened and unscrewed the grinder a total of 4 times before we were satisfied with the basic adjustment of the grinding level.

The Graef CM has an on/off button and grinds continuously. The grinding time cannot be programmed. That's why the ground coffee must be weighed manually.

"Dead Space" for Coffee Powder

Many other reviews also address this point—but for us it's almost incidental compared to what's mentioned above. Dead space is the coffee powder that is not dispensed after grinding. It backs up in the outlet of a grinder and is only pushed out by the coffee powder pushing from behind during the next grinding.

This powder is then not fresh and thus affects the taste. Depending on how long the last grinding was, the coffee tastes with slight aging notes.

The Graef CM 800 exhibits a large dead space through its relatively large nose in the dispensing area. Depending on the grinding level, up to 8 grams of coffee powder accumulated there (the finer the setting, the more). This can also lead to uneven extraction.

By tapping forcefully against the grinder, however, you can remove the coffee from the dead space before or after grinding.

Conclusion on the Graef CM800 and Who Is This Grinder For?

As already mentioned at the beginning: the Graef CM800 grinds espresso-fine. No other grinder can do that for the price. That's the biggest pro of the little grinder. But it's a problematic grinder for beginners.

If the preset outer grinding range doesn't match the coffee beans you're using, adjusting the grinder becomes very laborious. If you like to try changing beans, then good luck.

You can make espresso with the Graef CM 800. Compared to other grinders and what the coffee beans we tried can do, the grinder clearly doesn't tap the potential of the coffees.

Especially for high-quality, more complex coffees, we rather don't recommend the grinder. These already bring quite a bit of acidity with them, which is further amplified by the under-extraction acidity.

Due to the price, the Graef CM800 is the logical counterpart to the Delonghi Dedica EC 685, which many use as a beginner espresso machine. Of course, you can make espresso in the combination. But we predict a difficult relationship because neither partner really gives the other support.

Especially if you're new to the espresso world, it's important that your equipment does its job. Only then can you be sure you did everything right. For this reason, we especially recommend, in combination with an espresso machine like the Dedica EC 685, a grinder that runs solid and reliably.

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Footnotes:

1) In modern espresso preparation, sometimes there's deliberate avoidance of fines and instead work with a higher main peak. The prerequisite then is also fewer boulders.
2) Thanks at this point to the company UCC, whose equipment Benjamin was allowed to use for the analysis.