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Grinder & beans

Grinders & beans

An espresso machine can be as well thought out as possible, but when the wrong beans are used and the grinder is not adjusted correctly, good coffee cannot be produced. The following explanation will help you understand why. At first glance it may sound a bit complicated. However, it is only described in detail. If you manage it once, it will appear perfectly logical.

This is only one way to explain it. In whole or in part you will find other useful recommendations you can follow.

Beans

The roast of the beans must be specifically for espresso machines. Beans for filter coffee or fully automatic machines do not work well because they tend to produce sour tasting espresso. As explained below, getting a good result from pre-ground coffee will depend a lot on luck.

If the beans are too old then your effort will be in vain. It is generally not easy to define “old”, but at 3 months or more it starts to become questionable. Regarding this issue, you are in good hands with smaller coffee roasters. What you should never try: practice with old or cheap coffee. That’s like learning to cook with spoiled ingredients.

Some roasters offer so-called 3rd-wave roasts, which should have a “fresh acidity”. This is not suitable for everyone and is far from the espresso you may know from Italy. It is not recommended to start with such beans.

At the beginning you may consider to choose pure Arabica roasts because Robusta is often considered as having a heavy taste. But Robusta beans are not inferior coffee, and Arabica is not a sign of quality. They are just different.

The grinder

Good grinders have a stepless adjustment (or in very small steps). Grinders with timers are also useful as they allow one to grind consistent quantities.

If a grinder is new, it can produce odd results. You can skip this irritating phase quite well by grinding 500–1000 grams of cheap beans on medium-fine level (see below for explanations about the coarseness setting).

Coarseness

It is not easy to find the right coarseness setting at the beginning, which also varies from roast to roast. But it is also not so difficult and the following explanation should give you a good idea.

If you set the grinder to ‘very fine’, it will become blocked. This should be avoided, even though grinding discs made of steel will probably not be damaged. If you slowly change the coarseness while grinding to “finer”, you may hear a slight metallic sound before blockage occurs. It means that you have found the finest coarseness; now turn it back a bit so that the discs do not come in contact.

At this setting, the grinder will produce many lumps. The lumps may have a size of ~5 mm. If you pulverise the coffee between your fingers, it feels quite soft and you can hardly feel the coffee grinds. Even if it feels and smells great, this is too fine for any pump. But it’s a good starting point to find a suitable coarseness.

From now on, we adjust the grinder to a bit coarser. As a grinder has a so-called “dead space”, it always contains a few grams of ground coffee of the previous coarseness. This means that after changing the coarseness it will take a few seconds of grinding until you can notice a change. Continue to adjust the coarseness until you find only very few of these lumps in the portafilter; 1 or 2 mm lumps are perfectly fine. You will also notice that you can feel very small crumbs between the fingers.

The result may look like this (you might have even more coffee scattered around the portafilter due to trying to find the right coarseness):

Now you can stop adjusting the coarseness.

Some final tips:

To remove remaining lumps, simply stir it with a toothpick

Before tamping the coffee, knock the tamper against the portafilter to distribute the coffee.

 

Grind volume

The coarseness setting and bean roast are only 2/3 of the way to success. The following explanation helps to understand why the volume (of coffee) in the filter is of great importance.

Here is the set-up if too little coffee is filled. With the portafilter mounted, the ground coffee is designated in brown; the shower screen of the brew group is grey. Between both is some free space.

When you start pulling the shot, the water first fills the gap between the brew group and coffee, which then starts to bloat the ground coffee.

This may continue to get worse, and if you’re unfortunate, channelling may occur in which much of the water will flow directly through. This can be recognized when the coffee turns out very watery, and the flow from the portafilter is “dancing” and not quiet (which looks like the tail of a mouse).

After dismounting the portafilter you will see many holes on the surface of the coffee grounds, which will look wet and muddy.

But if you have the right volume of ground coffee, then the situation described above can be avoided and water will penetrate the coffee grinds very evenly:

Of course it is difficult to estimate the volume in a mounted portafilter. It’s roughly 5–8 mm from the surface of the tamped grounds to the upper edge of the filter. After pulling a shot and dismounting the portafilter you should see a light imprint from the shower screen in the coffee (with or without the imprint of a screw in the centre).

There is still a factor that influences a positive result: Tamping of the ground coffee. * The amount of pressure doesn’t play as important of a role as the equal distribution of the coffee grounds. It may be useful to tap the tamper 2 or 3 times against the filter to loosen clots and distribute the grounds. Whether you tamp the coffee with 5 or 15 kg (11 or 33 lbs.) of pressure doesn’t really matter.

Some people advise not to fill the filter completely, but to leave a very little bit of space. You can do that, but it’s difficult to be certain whether only 2 mm of space is remaining. On the other hand, the imprint of the screen can be easily checked after pulling a shot and dismounting the portafilter.

What is more often a hindrance than help is the so-called ideal amount of 7 g (or 14 g) per espresso. Normally more grounds are filled into the portafilter and that is also highly dependent on the type of roast. So this isn’t exactly doctrine — the main thing is that it works and tastes good. At a later point when you feel very familiar with your machine, it’s ok to try to approach the ideal 7 grams step by step.

Cup and portafilter

The cup should be thick-walled and have a round bottom. It should have already been well heated (if it was on the heating tray of the machine or filled with hot water). And before pulling your first shot, the portafilter should be mounted and empty at least 15 minutes after switching on the machine. The reason for this must-do is simple: there are only 25 ml (up to 60 ml) of water for an espresso, which cools very quickly on cold surfaces. The result will be an espresso that tastes dull or sour, which could be easily avoided.

In conclusion, here are a few details that could be useful in certain circumstances:

A new bag of roasted coffee (even the same kind) may require a new coarseness setting.
Changing weather conditions may also require an adjustment to the coarseness.
By adjusting to a finer coarseness, the grinder takes more time to get the same volume — and vice versa. That’s important to know when using a grinder with a timer, which should be adjusted accordingly.
As already mentioned, a grinder has a dead space. After adjusting the grind coarseness, you will not notice any significant difference. If you keep compensating immediately, it won’t be long before men in white coats come to take you away — or at the very least you’ll waste large amounts of coffee.
Changing the coarseness should be done only in very small increments.
If the grinder is scattering the coffee, the reason may be the type of roast.
Sample packages (with small amounts of roasted beans) are a good idea, but whoever can nails the right coarseness and volume with only 250 g could be considered a natural born barista.
If all of this is taken into consideration, the coffee puck will be quite dry and will fall out like a cake after extraction (more or less in one piece). The extraction will be steady, and after 15-25 seconds the coffee comes out increasingly brighter. In about 25 seconds a normal espresso is ready and you should have around 25 ml (double espresso: 50 ml) in the cup. Espresso should taste neither acidic nor bitter, but intensely tart.
* Concerning the tamper: It is not necessary to use a luxury model for 30 € or more. Generally, tamping would work with the open hand or the bottom of a nearly matching water glass (about 58 mm diameter). But if you look at the tamper as jewellery, then you can spend a lot of money. If you’re on a budget, a 10 € tamper will do you just fine. And who knows? Maybe one day you’ll get a beautiful tamper as a gift.

Finally, some details that may be helpful:

• A new bag (even of the same roast) may require an adjustment to your coffee grinder’s setting.
• The same is true during significant changes in the weather.
• If you change your grind setting in the direction of “finer”, it has to grind longer to achieve the same volume. That’s important to know when using a timer, which should then be adjusted.
• As stated above, some grinders have a dead space. After grinding one portion, no significant difference will be noticed. If you immediately change the grind size again, you’ll be on your way to the madhouse, or at the very least waste a lot of coffee.
• Always adjust the grind setting in small increments.
• If the grinder is scattering a lot, this could be due to the roast or the beans.
• Sample packs (small amounts of different roasts) are well intentioned, but if you can manage to get something out of 250 grams before it’s almost gone, then you’re a natural born barista.

If you’ve taken all of this into consideration, your brewing experience should resemble the following description:

• The coffee will pour out evenly. After about 15 seconds the colour should become increasingly brighter. A normal espresso is finished after about 25 seconds, leaving you with approximately 25 ml (0.9 fl oz) for a single shot (or 50 ml [1.8 fl oz] for a double).
• After extraction you should be left with a very dry coffee puck in the basket, which should fall out more or less whole.
• The taste of the espresso is neither sour nor bitter, but rather very tart.

* Regarding the tamper: It doesn’t have to be a deluxe piece for 30 or more Euros. You could just as effectively tamp with the heel of your hand or the bottom of a water glass (approx. 58 mm in diameter). If you view the tamper as an ornament, then you can spend that amount. But if money is tight, you will do just as well with a 10-Euro tamper. Let someone buy you your dream tamper as a gift.

For more detailed information, click here. Some things may be described differently, but there are also many roads leading to Rome.

 

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