The Graef CM800 is frequently cited as THE entry-level grinder for the world of espresso. At just under 130 euros / 150 Swiss francs, it also beats many other products currently on the market in terms of price.
But what is the little grinder actually capable of, the one recommended by many forums and receiving decent to good reviews?
We tested the Graef CM 800. After the first few hours with the grinder, our impression was not good. Frankly speaking: we swore, we were frustrated, and the coffee did not taste good.
When a device performs poorly or partially poorly in one of our tests, the following happens:
- we test even more intensively to substantiate our impression objectively.
- we look for ways to resolve the weaknesses of a piece of equipment or provide you with 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 back on our table and was tested by us in a comparison with 24 other home espresso grinders. Both tests have been incorporated into this report and two videos.
Why do we test and why do we test at all?
Before I dive deeper into the grinder, I would like to briefly preface why we test coffee machines and grinders at all. Die Kaffeeschule is a coffee school. We also roast, manage a coffee farm in Nicaragua, and run two cafés in Basel. This grinder test and all others come directly from our coffee academy.
Our goal is that as many of you as possible can drink good coffee with simple means. We are convinced: if many coffee drinkers drink good coffee, the willingness to spend more money on good coffee beans increases, and the producer benefits from this. As long as espresso machines, grinders, or water limit the quality of the coffee (or ruin it), no good coffee will be used.
So, if we recommend a machine to you, it is because we believe you can make good coffee with it. And if that requires some tips, we provide them. Unlike many review portals, we do not make our living from you buying the machine through an affiliate link.
If you compare our articles, comparisons, and tests with classic review portals, it becomes clear that our tests are much more multi-layered. We don't sugarcoat anything just so you end up buying bad equipment.
We tested the Graef CM800 in good company. On one hand with the La Marzocco GS3 and on the other alongside a Cimbali M100.
Overall impression of the Graef CM 800
The greatest strengths of the small Graef CM 800 are its price and size. With a depth of just 13.5 cm, a width of 23 cm, and a height of 39 cm, it fits into any kitchen nook. With its aluminum housing and a weight of around 2.6 kg, it also seems quite solid.
Anyone who manages to adjust the grinder well can also make espresso with the Graef CM800! This grinder is an espresso grinder, unlike many other grinders in the sub-€200 range. Most grinders from Tchibo, Melitta, Rommelsbacher, and co. are filter coffee grinders and cannot be set fine enough! Do not let misleading reviews steer you off course here.
Our conclusion on the Graef CM 800 up front
- Can you make espresso with the Graef CM 800? Yes, it is possible.
- Is it easy to use? No. If you are not lucky and the grind range is somewhat correct, the Graef is very laborious to operate.
- Who is this grinder suitable for? Not for sensorially demanding coffee drinkers. You should also be able and willing to handle a screwdriver.
- The Graef CM800 is sensorially suitable for beginners and technically for advanced users.
Grinding espresso fresh with the Graef CM800
Freshly ground coffee is always better than pre-ground. Within just 15 minutes, a large portion of the coffee's volatile aromatic components has vanished. Therefore, the first step towards better coffee is to get a grinder that allows for minute-by-minute grinding.
Generally, one distinguishes between espresso grinders and filter coffee grinders. Espresso grinders allow for a finer grind setting. 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 is why it is very important to ensure when choosing a coffee grinder that it 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 most affordable 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 so cheap be delicious?
We put many hours of work into the test of the Graef CM800. This was due to the complex grind size adjustment and the fact that we were not satisfied with the taste result.
I tested the grinder first. Afterward, professional barista and vice-barista champion Michel Aeschbacher worked with the grinder. Although we brewed espresso, none of them really convinced us. To rule out that the taste result was limited by the espresso machine, we worked with a professional espresso machine as expensive as a small car (La Marzocco GS3/Cimbali M100). The espresso was our Standard Coffee Dreispitz, which we serve in our Kaffeeschule Café at Basel train station.
The espresso was bitter on one hand and at the same time had a higher proportion of aggressive acidity. We brewed the espresso with a classic brew ratio of 1:2.5. 18 grams of coffee in the portafilter yielded two espressos of 22.5 grams each with a brew time of 25 seconds.
To verify the result, we compared the espresso with the same parameters against 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 identical in taste and one is different. The different cup is marked from below, invisible to the taster.
The test subject has the task of finding the different cup in each case. In this case, we doubled the test series and set an additional task: to state which cup tastes worse.
Across all 6 sets, I found the different cup in each case and selected the ones that tasted worse as the extractions from the Graef CM 800.
But why does the Graef CM 800 have trouble keeping up with the other grinders in terms of taste?
Grind particle distribution as a reason for bad espresso
The assumption was that the distribution of the grain size of the ground coffee is very different. Every coffee grinder has a spread of particles of various sizes. This is also the case with the Graef CM 800. The only question was how pronounced the number of different sizes is. The better a grinder is, the larger the number of particles in the desired range. If many fine particles and, above all, many coarse particles are present alongside the main peak, these extract differently than the desired particle size.
Depending on the particle size, it is easier or harder for the brewing water to effectively extract the grounds. Finer particles extract much more easily than coarse particles.
It is much easier for the brewing water to penetrate the coffee grain and extract everything in small particles. For coarser particles, the effort is significantly greater, and only a low extraction is achieved.
We are talking here on a macro level about under- and over-extraction! It's not about whether a whole cup of coffee tastes over- or under-extracted, but rather how many particles as a whole are well-extracted. 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. Didn't we write that earlier today? Exactly, further up in the taste description of the espresso we brewed with the Graef CM800.
Particle distribution of the Graef CM800The curve above illustrates the particle distribution curve of the Graef CM 800. The X-axis shows the particle size in microns and the Y-axis shows the volume of the corresponding size in percent. It is typical for a grinder to have a distributed curve. This usually manifests in two main peaks – a fine one and a coarser one.
Before we go into more detail about the curve, a quick note on our further procedure. We do not have the possibility in our coffee academy to perform particle analysis via image or laser analysis. These devices are incredibly expensive, in the six-figure range. However, there is a simpler method, namely a laboratory sieve. Michel Aeschbacher examined the proportion of the finest and coarsest particles with two micron sieves of size 800 and 400.
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 clarify the situation. The typical espresso peak lies somewhere between 300 and 600 microns. With the Graef, there is still quite a lot that is coarser. Some particles are really as large as grains of sugar. While fine particles definitely have a task in the range of espresso extraction, coarse grains are a real problem. Fine particles sit between the larger ones and help to build up sufficient resistance.(1) Coarse particles cannot be successfully extracted in the short brew time of espresso extraction (approx. 25 seconds) and therefore contribute strongly to an unpleasant under-extraction acidity. In addition, they facilitate channeling, as they make a compact coffee bed difficult.
Front left coarser than 800, right between 400 and 800 and back finer than 400. Espresso extraction time: 25 seconds, 50 grams.
Grind size analysis via laser and image acquisition
After the sieve test, we wanted to have our results externally verified. Coffee professional and roaster Benjamin Schütz helped us with this.(2) I also spent a day with the company Symphatec and compared very different grinders and grindings. This helped me personally to better understand the specific surface area of ground coffee.
I adjusted the espresso on six grinders so that it yields 50 grams of final weight in the cup in as close to 25 seconds as possible using 18 grams of coffee. At this grind level, I ground 200 grams of coffee as a sample from the following grinders.
Anfim Practica as a professional benchmark, Eureka Mignon Perfetto, Macap M2D, Sage Smart Grinder Pro, Sette 270wi, Graef CM800.
The grounds analysis yielded the following picture:
Comparison of particle distribution of 6 espresso grinders.
May be used when linking 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 largest proportion of coarse particles.
This visual representation explains quite well what we experienced sensorially with the grinder. The measurements of the extractions in comparison also substantiate the low extraction evaluation.
Lowest strength and extraction evaluation with the Graef CM800
Using the values mentioned above, I adjusted the espresso, took the grind samples, and of course also carried out a comparison of strength and extraction.
Strength is the concentration of dissolved particles 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 quantity (volume of espresso in grams * TDS % / amount of coffee powder used).
I came to the following results.
| Grinder Name | Powder Amount | Time | Volume/g | TDS | Extraction |
| Sage Smart Grinder Pro | 18.00 | 24.50 | 49.8 | 7.50% | 20.75% |
| Graef CM 800 | 18.00 | 25.50 | 49.6 | 6.52% | 17.97% |
| Eureka Mignon Perfetto | 18.00 | 25.50 | 49.8 | 7.10% | 19.64% |
| Macap M2D | 18.00 | 24.50 | 49.6 | 7.64% | 21.05% |
| Sette 270 | 18.00 | 25.00 | 49.4 | 6.95% | 19.07% |
| Anfim Practica | 18.00 | 24.50 | 49.2 | 7.88% | 21.54% |
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 manifests sensorially just the same: the espresso tastes waterier and less creamy and mouth-filling in comparison to the other espressos. The lower extraction manifests in the already described more pronounced acidity.
Grinder Test 2022 - Graef CM800 under the magnifying glass again
As part of our current espresso grinder test series, we were back in the lab with seven ground samples from the Graef CM800. The result confirmed our measurement from back then. In the entire field of 24 espresso grinders, the Graef CM800 comes in with the third-broadest coarse peak and a correspondingly lower peak. This is an expression of the large scatter and shows how hard the Graef struggles to grind coffee particles precisely.
The difficulty in dealing with the Graef also shows in another category. In principle, the particle distribution curve shown above displays the same grind setting four times. Effectively, the grind settings differ significantly every time.
The following list reflects the data that leads to the graph shown above. In all four essential measured values, the numbers jump from shot to shot.
In the context of all other grindings, the following graphic also shows that the Graef CM800 falls out of the field of better grinders.
Operation and grind adjustment of the Graef CM800
Up to this point, I have already intensively described the results of the grinder, but I have not yet gone into the grind adjustment. That is a very important function, because the run-out time of the espresso can also be controlled via the adjustment of the grind size. The finer the grind, the greater the resistance for the brewing water, and the longer the espresso runs accordingly. The coarser the grind, the faster the water shoots through the coffee grounds and the faster the espresso is in the cup.
Grind adjustment of the Graef CM800
The Graef CM800 features a grind adjustment of 0 – 40. That means little at first. The central question is how much the grind can be effectively adjusted with it. The outer adjustment is very easy to perform and can be done by any user without further ado.
However, we had the problem that we did not get an acceptable result with the 40 levels. Our espresso ran through within 12 seconds even at the finest grind setting. This can be, for example, because a coffee is lighter roasted or it has a different density due to the cultivation altitude. In any case, the espresso ran way too fast.
The solution is to adjust the inner grind disc setting to be finer. For this, the grinder must be opened. Afterward, two small screws can be removed from the upper grind disc insert and it can be set finer or coarser this way. It's best to watch our video for this.
Because otherwise, what happened to us during the first changes will happen to you. If you don't reinsert the grind disc insert correctly, then the grinder not only fails to implement your desired adjustment – it is completely operating at a different level (much coarser).
We didn't get smart from the manual itself. A YouTube film from Graef itself then made the function clear to us. We think: the entire adjustment of the grinder 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 screwing starts.
This is really not solved well at all. Other devices, such as the Sage Barista Express, sometimes make it necessary to readjust the grinder. But that works without a screwdriver, and above all, the insertion of the cone is self-explanatory.
In any case, our mood was not upbeat after setting up the grinder, and we have really set up many grinders already. For these reasons, we do not recommend the grinders to anyone who is new to making espresso. The frustration potential is too great here in our view. We opened and unscrewed the grinder a total of 4 times until we were satisfied with the basic adjustment of the grind size.
The Graef CM has an on/off button and then grinds continuously. The grinding time cannot be programmed. Therefore, the grounds must be weighed manually.
“retention” for coffee powder
Many other reviews also address this point – but for us, it is almost secondary next to the ones mentioned above. retention is the coffee powder that is not dispensed after grinding. It accumulates in the exit of a grinder and is only pushed out during the next grinding by the coffee powder pushing from behind.
This powder is then just not fresh and thus influences the taste. Depending on how long the last grinding was, the coffee then tastes like slight aging notes.
The Graef CM 800 exhibits a large retention due to its relatively large nose in the output area. Depending on the grind setting, up to 8 grams of coffee powder accumulated there (the finer, the more). This can also lead to an uneven extraction.
However, by vigorously tapping against the grinder, the coffee can be removed from the retention before or after grinding.
Conclusion on the Graef CM800 and who is this grinder for?
As already said at the beginning: the Graef CM800 grinds espresso-fine. No other grinder for the price can do that. That is the biggest pro of the small grinder. But it is a problematic grinder for beginners.
If the preset outer grind range does not match the coffee beans you are using, then adjusting the grinder becomes very laborious. If you want to try changing beans, then goodnight.
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 does not call up the potential of the coffees.
Especially for high-quality, more complex coffees, we rather do not recommend the grinder. These already bring quite a bit of acidity with them, which is 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 an entry-level espresso machine. Of course, it is possible to make espresso in this combination. But we predict a difficult relationship, because neither of the two partners provides real support.
Especially when you are new to the espresso area, it is important that your equipment fulfills its task. Only then can you be sure that you did everything right. For this reason, we recommend a grinder that runs solidly and reliably, especially in combination with an espresso machine like the Dedica EC 685.
Footnotes:
1) In modern espresso preparation, fine particles are sometimes deliberately omitted, and instead, work is done with a higher main peak. A prerequisite, however, is fewer bolders.
2) Many thanks at this point to the company UCC, whose device Benjamin was allowed to use for the analysis.
