If you're looking for the best espresso grinder to start your journey into the world of espresso, there's no way around the Delonghi KG521. The Kaffeemacher is already available in Switzerland for around 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.
However, affordable often has its limits, and with grinders at the lower end of the price scale, the limit often shows itself in the grind size. Many grinders advertised as espresso grinders don't grind fine enough and therefore only deserve the stamp "coffee grinder" and not "espresso grinder".
How does the Delonghi KG521 perform here, which is considered 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 coffee powder that's too coarse?! The Delonghi KG521 doesn't grind many coffees fine enough!
What does not fine enough mean? A typical espresso requires a brewing 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 couldn't get beyond an extraction time of 19 seconds with any coffee. In some cases, the coffee shot into the cup in under 15 seconds. Is that bad? Well, it tastes that way. 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 we didn't get any further by overdosing either. A higher dose, e.g. 19 grams of coffee instead of 18, increases the resistance - but didn't help us here. With our grind size 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 standard configuration.
Tricks, Reasons, and Possibilities
The question remains why the Delonghi KG521 is still popular among espresso beginners. There's a reason for that! The grinder is sold as a counterpart to the Delonghi Dedica EC685. We find this small espresso machine interesting too. 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 basket. The basket itself creates the resistance that in classic baskets and espresso machines is created by the particle distribution of the coffee powder. The entire espresso must be forced through a tiny hole in these "fake baskets".
The basic idea of these baskets is to be able to prepare bad, old, or pre-ground coffee and still build espresso crema through excessive artificial pressure. These baskets 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 cannot achieve an espresso grind size. However, with the help of the double-walled basket, 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 still tastes bad.
So we recommend a different trick. For once, we're not going lower but higher.
Tuning the Grinding Mechanism - Raising the Cone
The Delonghi Dedica is a coffee grinder with a conical grinding mechanism. A lower cone protrudes into an upper grinding ring. The higher the cone pushes into the ring, the finer the grind size. To reduce the distance, we install a washer under the lower cone. We assume no liability if you rebuild this modification. Modifications are at your own risk and may result in 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 size is set beyond coarse - this allows the upper cone to be removed as for cleaning (see grinder manual).
A cloth is placed on the cone to prevent scratches when touching it with the pliers. Using pliers, the grinding disk is now carefully loosened by turning it clockwise. For us, this loosening was relatively easy once we had a good grip with the pliers.
The cone is unscrewed as well as the subsequent plastic suspension and the felt washer. Below that are two thin washers, which are also removed.
For our grinder upgrade, we bought a third washer at the hardware store. (If anyone finds an online link to an appropriate washer, please send it. Thanks!) A washer with the same diameter that is overall 1/3 thicker than the existing washers will also work. The installed washers have an inner diameter of 10mm and an outer diameter of 13.5 mm. They are so thin that our caliper couldn't provide an accurate result. It's approximately 0.4 mm.
We put the three washers back in, reassembled the remaining removed parts, and tested the grinder. It's important not to immediately use the finest grind size, but to approach it slowly. The grind size range now shifts overall towards finer. If you quickly switch to the finest grind size, you risk metal rubbing on metal and the grinder becoming dull.
How does the espresso taste after tuning?
Quite remarkable: a tiny washer brings the Delonghi KG521 back into play. The double espresso, pulled with 18 grams of finely ground coffee and 45 grams of Apas Espresso (try in Germany or in Switzerland) in the cup scored 10 points higher on our rating scale.
Retention, Speed, and Consistency
Tuning doesn't suddenly turn the Delonghi KG521 into a really good espresso grinder. But it becomes an option in the entry-level espresso range and at a relatively low price.
Several arguments further support the grinder. At 86.2 decibels, the KG521 belongs to the category of grinders with medium loudness. In terms of retention, the grinder performs well with only 1.4 grams. With a difference of only 0.2 grams when single-dosed and ground for over 30 seconds, the Delonghi KG521 is even suitable as a grinder for single dosing/single portions. However, with a coffee output of 17.1 grams in 10 seconds of grinding, the grinder is one of the slower espresso grinders.
The impression also remains poor in terms of consistency and especially usability. While the consistency with a standard deviation of 0.28 grams of coffee matches the average pull, it is often impossible to program the desired amount of coffee.
The dosing adjustment on the rotary dial on the outside right of the grinder only allows coarse adjustments in four to six gram steps. 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 grind amount of 18.2 grams. If the desired amount had been 19 grams, achieving it with the coarse grind amount 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 one hand, we hadn't yet discovered the modification option. On the other hand, we initially tested all grinders and espresso machines in their as-delivered condition, because that's how you receive the equipment. In our view, the trip to the hardware store or specialty shop and the improvement of a grinder with tools and non-included accessories should not be expected of customers.
Our grinds were correspondingly coarse and the fine particle content was correspondingly low compared to other grinders. But as written, this was due to the limited adjustment capability of the grinder. However, we could draw one insight 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 again to the finest grind size. Now we expected that the grinder would spit out the same particles relatively precisely again and a corresponding particle distribution curve. After all, we could simply set the grind size slider back to 1 or the finest grind size. But the curve taught us better. There was a surprisingly large difference between the two curves, which results in poor precision across multiple pulls.
Delonghi KG521 Coffee Grinder Conclusion
We're looking for an espresso grinder to recommend in the lowest price category. The Delonghi KG521 is not that grinder. In factory delivery, the grinder does not achieve the desired grind range even at the finest grind size. The grinder grinds too coarsely. Only through the performed upgrade does espresso-fine grinding become possible.
So the grinder can only be recommended if the home barista has the desire and joy to take out the pliers and search for a suitable washer. Then the Delonghi KG521 is indeed an option in the range of affordable espresso grinders.
We particularly like that the grinder does a good job as a single-portion grinder. That's a nice option for home use. The usability and setting of the coffee amount is impractical, but plays a lesser role when using it in the single-portion range.
To all other tests and the other espresso machines in the 80 - 150 euro price range.
