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By Boutique Limoilou

Avoid bitterness with an Italian coffee maker, is it possible?

Invented in 1933 by Alfonso Bialetti, the Italian coffee maker, commonly known as themoka pot, seems, at first glance, so easy to approach. Affordable and requiring only a few basic manipulations before arriving at a result, this method of preparation has spread in homes. If it tends to produce tight and very bitter coffees, the Italian coffee maker requires a little more work to achieve a cup with more balanced flavors.

Some of you have rediscovered the Italian coffee maker after watching the recentvideos by popularizer James Hoffmann. We are made to realize that the Italian coffee maker is a much more complex tool than expected, that it is easier to achieve a bitter cup than a balanced one, given the design of the device. The Société des Cafés team has decided to offer you an overview of this preparation method, which is one of the most emblematic in Italy.

What are the reasons for bitterness?

Cup bitterness can be caused by 21 different sources: caffeine, certain acids and proteins, and chlorogenic acids. When one or more of these elements are over-extracted, they overpower the sugars and flavors, which turns your cup into an astringent, unbalanced and, according to many, unpleasant in the mouth coffee. Bitterness can come from roasting, but also from certain manipulations carried out during the preparation of the coffee:

  • During the roasting process, a reaction can be particularly damaging to the organoleptic qualities of a coffee, i.e. when the chlorogenic acids contained in the green beans break down into quinic and caffeic acids. While quinic and caffeic acids give the cup a so-called pleasant bitterness, prolonged contact of the beans with high heat transforms them into much more bitter compounds: phenylindanes. These are found in high concentrations in dark roast coffees, often giving them a very toasty, not to say ashy or burnt profile. Although we associate the bitterness of a coffee with its dark roast, under-roasted beans can also give off a more grassy bitterness, which can become just as unpleasant.
  • Flats during the preparation can also be the source of this imbalance in the flavors. If you grind your beans too finely, use water at too high a temperature, or extend the contact time between the coffee and the water, these elements will make your cup possibly more bitter. The reason is simple: too many bitter compounds have literally been squeezed out of the beans and are now ending up in your brew.

Thus, the two main causes of poor cup bitterness are the use ofoldbeans, of poor quality or very dark roasted as well as over-extraction of the coffee during preparation. Bitterness is not negative as such. It can bring depth and complexity to the cup, rounding out flavors and balancing acidity. It is therefore a desirable characteristic when measured.


How the Italian coffee maker works?

Contrary to popular belief, the Italian coffee maker does not prepare espressos. It produces within its system onlya pressure of 1-3 bars, while an espresso machine produces one of 8-10 bars ideally. However, it is not wrong to refer to espresso in order to describe the intensity of the flavors and the high concentration of the coffee produced by themoka pot. Indeed, a coffee produced with an Italian coffee maker generally has a ratio of 1g of coffee for 10g of water. For espresso, we are talking more about a ratio of 1g to 2g. Thanks to the metal filter that lets more oils slip into the cup, you can also obtain a very textured coffee, thicker in the mouth. More often than not, the result is robust, woody, full-bodied.

For example, for the Italian coffee maker 3 cups, we are talking about 14 grams of coffee for 140ml of water so that there is water under the exhaust valve.

Its device is made up of three distinct chambers. The lower one is used to contain water; the middle one, to put the ground coffee and the last one, to collect the infused liquid. Under the heat of the stove, the water vapor accumulates and the air expands in the lower chamber. The pressure increases and allows the hot water to rise through a channel towards the coffee to end up in the upper container.

If all you need is a heat source, water and ground coffee to achieve a result with the Italian coffee maker, its manufacturing material (aluminum or stainless steel) tends to retain as much heat as possible, which causes the temperature of the water to skyrocket and influences the compounds that are extracted from the coffee. The precipitous increase in temperature precedes the bubbling phase (when bubbles come out of the channel in the upper chamber of the Italian coffee maker), which is also to be avoided. The challenge with the Italian coffee maker is to maintain a moderate temperature, but sufficient to pass as much liquid as possible through the coffee before the inevitable bubbling phase.

What are the tricks to avoid excess bitterness during extraction?

Let's assume you're using fresh beans that are light to medium rather than very dark roasted, which will up a notch your chances of getting a nice balance in the cup. Very dark roast beans will tend to develop robust and bitter flavors, extracting such coffee with the Italian coffee maker will push these characteristics forward. Once the grains have been selected, here are some tips for obtaining a good extraction:


  1. Heat some water (not to boiling point) before putting it in the bottom reservoir of your Italian coffee maker up to the exhaust valve. This additional step reduces the contact time of the coffee with the water and avoids over-extracting the coffee. The Italian coffee maker tends to get very hot (above 100°VS), which promotes the appearance of acrid, even burnt notes.
  2. Fill the basket with freshly ground coffee, but above all do not tamp it with a coffee press. By compacting your coffee in this way, you increase the pressure in the lower chamber and the water has a harder time passing through the coffee. The safety valve will then be very useful. For the Italian coffee maker to work at its best, we suggest simply forming a flat surface with the ground coffee..
  3. Put the ring on low heat. This keeps the pressure and the temperature more stable during the preparation of the coffee, without these two variables increasing exponentially. As soon as the liquid appears in the upper container, put the fire at the lowest possible intensity. If the flow at the outlet becomes faster and faster, remove your Italian coffee maker from the heat. On the contrary, if the flow tends to slow down, slightly increase the intensity.
  4. Keep the lid up during the extraction, so you can have the right time on the progress of the extraction.
  5. Quickly turn off the extraction, once the bubbling phase begins. Run cold tap water over the lower reservoir or wrap the Italian coffee maker in a damp towel. Immediately pour the coffee into your cup so as not to leave it in contact with themoka potwhich is, no doubt, now burning hot.

The Italian coffee maker can prepare excellent coffees, whether you take them like this, lengthened with water or covered with frothed milk or any other vegetable drink. With these few tips, we think you can really take your cup results up a notch by eliminating the intensity of the bitterness that is produced from the start.moka pot, and thus, discover the other flavors that are hidden behind. In addition, if you are a latte lover, with Bialetti's manual milk frother, it is possible to achieve a considerably creamy milk froth manually.


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Research and writing: Chloé Pouliot


Garrett Oden, 7 Common Moka Pot Questions Answered, inJava Press.
Garrett Oden, How To Taste Coffee: Bitterness, in Java Press.

James Hoffman,The Moka Pot (Episode #1-2-3).

Sophie L. Rovner, Tweaking Coffee’s Flavor Chemistry, inChemical & Engineering News.

Sara Marquart, The Art and Science of Roasting: Bitterness, inEuropean Coffee Trip.