If you're looking for the best espresso grinder to get started in the world of espresso, there's no way around the Delonghi KG521. The coffee grinder is already available in Switzerland for 120 francs and is offered in Germany from 140 €. This makes the Delonghi KG521 one of the affordable grinders in our large espresso grinder comparison.
But affordable often has limits, and with grinders at the lower end of the price scale, the limit often shows in the grind size. Many grinders advertised as espresso grinders don't grind fine enough and therefore only deserve the label "coffee grinder" and not "espresso grinder".
How does the Delonghi KG521 perform here, which is marketed as the logical counterpart to the entry-level espresso machine Delonghi Dedica EC685? We cover this and much more in our espresso grinder test and coffee video. And of course, we also provide important tips and tricks to get the most out of your grinder.
The Limits of Grind Size
Let's not beat around the bush - or should we say - the too coarse coffee powder?! The Delonghi KG521 doesn't grind many coffees fine enough!
What does not fine enough mean? A typical espresso requires a brew time of 25 seconds. Many coffees should even be brewed longer to achieve the best possible grind size.
We ultimately tried three different coffees and didn't get past an extraction time of 19 seconds with any coffee. Sometimes the coffee shot into the cup in under 15 seconds. Is that bad? Well, it tastes like it. Such a short extraction time leads to a strongly emphasized, unpleasant acidity in taste. In technical terms, a quick pull is also referred to as underextraction.
And overdosing didn't help us either. A higher dose, e.g. 19 grams of coffee instead of 18, increases resistance - but didn't help us here. With our grind setting, we were already at the finest possible grind size of the espresso grinder.
In other words: the Delonghi KG521 failed as an espresso grinder in its basic configuration.
Tricks, Reasons and Possibilities
The question remains why the Delonghi KG521 is still popular with espresso beginners. There's a reason! The grinder is sold as a counterpart to the Delonghi Dedica EC685. We also find this small espresso machine interesting. So far, we haven't found a better, cheaper espresso machine that we can recommend for beginners.
The Delonghi Dedica EC685 comes with a double-walled shower screen. The screen itself provides the resistance that classic screens and espresso machines create through the particle distribution of the coffee powder. The entire espresso must be forced through a tiny hole on these "fake screens".
The basic idea of these screens is to be able to prepare bad, old or pre-ground coffee and still build up espresso crema through excessive artificial pressure. These screens do their job, but are not suitable for brewing really good espresso. We've dedicated a video to the upgrade of the Delonghi Dedica.
The Delonghi KG521 coffee grinder alone doesn't achieve an espresso grind. With the help of the double-walled screen, however, a slow extraction can be created that looks as if the espresso is well adjusted. But this trick only works for the clock and the eye. Bad always tastes bad.
So we recommend a different trick. For once, we don't lay it deeper but higher.
Tuning the Grinder - Raising the Cone
The Delonghi Dedica is a coffee grinder with a conical burr. A lower cone protrudes into an upper burr ring. The higher the cone penetrates into the ring, the finer the grind size. To reduce the distance, we install a shim under the lower cone. We assume no liability if you rebuild this modification. Any modifications are made at your own risk and may result in a loss of warranty for your espresso grinder.
First, we remove the bean hopper after the remaining beans have been ground. The Delonghi KG521 is disconnected from power. The grind setting is set to coarse - this allows the upper cone to be removed like for cleaning (see grinder manual).
A cloth is placed on the cone to avoid scratching when touching with pliers. Using pliers, the burr is now carefully loosened by turning clockwise. For us, this loosening went relatively easily once we had good grip with the pliers.
The cone is unscrewed as well as the subsequent plastic bracket and the felt washer. Below that are two thin shims, which are also removed.
For the upgrade of our grinder, we bought a third shim at a hardware store. (If any of you find a link to an appropriate shim online, please send it. Thank you!) A shim with the same diameter that is overall 1/3 higher than the existing shims will do the trick too. The installed shims have an inner diameter of 10mm and an outer diameter of 13.5mm. They are so thin that our caliper could not provide an accurate result. It's about 0.4 mm.
We put the three shims back in, rebuilt the remaining removed parts, and tested the grinder. It's important not to directly apply the finest grind size, but to approach it slowly. The grind size range now shifts overall towards finer. If you go too quickly to the finest grind size, you risk the metal rubbing on metal and the grinder becoming dull.
How Does the Espresso Taste After Tuning?
Quite remarkable: a tiny shim brings the Delonghi KG521 back into play. The double espresso, pulled with 18 grams of finely ground coffee and 45 grams of Apas Espresso (available in Germany or in Switzerland) in the cup tasted 10 points better on our rating scale.
retention, Speed and Consistency
Tuning doesn't suddenly make the Delonghi KG521 a good espresso grinder. But it becomes an option in the entry-level espresso range at a relatively low price.
Some arguments also speak in favor of the grinder. At 86.2 decibels, the KG521 belongs to the group of grinders with medium volume. In terms of retention, the grinder performs well with only 1.4 grams. With a loss of only 0.2 grams when dosed individually and ground for over 30 seconds, the Delonghi KG521 is even suitable as a grinder for single dosing. However, with a coffee output of 17.1 grams at 10 seconds of grinding time, the grinder is one of the slower espresso grinders.
Also in terms of consistency and especially usability, a poor impression remains. While the consistency with a standard deviation of 0.28 grams of coffee is in line with the reference average, it is often impossible to program the desired amount of coffee.
The dosing setting on the rotary dial on the far right of the grinder only allows coarse adjustments in four to six gram increments. With another "Light - Normal - Strong" scale, fine adjustments can now be made in two gram increments. With dial setting 5, we jumped to 22 grams of coffee in the bean hopper at the Strong setting. Normal resulted in 20 grams and Light led to a ground amount of 18.2 grams. If the desired amount had been 19 grams, achieving it with the coarse grind setting of this grinder would not have been possible.
Precision and Particle Distribution
We performed our particle distribution measurements with the grinder without tuning. On the one hand, we hadn't yet discovered the possibility of modification. On the other hand, we tested all grinders and espresso machines initially in their as-shipped condition, because that's how you receive the equipment. In our view, going to a hardware store or specialty shop and improving a grinder with tools and equipment not included should not be expected of customers.
Accordingly coarse were our grinds and accordingly low was the fine particle content compared to other grinders. But as mentioned, this was due to the grinder's limited adjustment options. However, we were able to draw one conclusion from the particle distribution measurements.
In test 4, we set the grinder to the finest possible grind size. Test 5 was the ristretto setting on other grinders, which was of course not possible with the KG521. In test 6, a café crème was set. In test 7, we set the grinder to the finest grind size again. Now we expected the grinder to spit out the same particles relatively precisely here and a corresponding particle distribution curve. After all, we could simply set the grind slider back to 1 or the finest grind size. But the curve taught us otherwise. There was surprisingly large difference between the two curves, which resulted in poor precision across multiple pulls.
Delonghi KG521 Coffee Grinder Conclusion
We're looking for a recommended espresso grinder in the lowest price category. The Delonghi KG521 is not that grinder. In factory condition, the grinder doesn't reach the desired grind range even at the finest grind size. The grinder grinds too coarse. Only with an upgrade is espresso-fine grinding possible.
Therefore, the grinder can only be recommended if the home barista enjoys pulling out the pliers and looking for a suitable shim. Then the Delonghi KG521 is indeed an option in the range of affordable espresso grinders.
We particularly like that the grinder does good work as a single-dose grinder. This is a nice option for home use. The usability and setting of the coffee amount is inconvenient, but plays a lesser role when used in the single-dose range.
For all other tests and the other espresso machines in the price range 80 - 150 euros.
