Coffee preparation guide: the 4 Ms of espresso

An essential concept for those who want to get the most out of the experience of tasting an espresso, the 4M concept is internationally recognized . It designates 4 important parameters to master when extracting an espresso.

• Miscela – The coffee blend
• Macinadosatore – The dosing mill
• Mano – The hand, the barista technique
• Machina – The espresso machine

These parameters are linked in such a way that a disruption of one of them will transform your exquisite beverage into a foul wine.

It is also faced with the adjustment of these elements that many espresso drinkers decide to opt for a simpler solution with full-automatic machines or a capsule aberration.

But be sure that there is only the manual method and mastery of the 4Ms to obtain a divine cup. We then talk about technique, art, sensation which, over time, will give you an extraordinary espresso.

Let's now look in detail at these elements that I like to present in this order:

Miscela – The coffee blend

A filmmaker who took images using a professional camera once told me: “A good video doesn't happen during editing but beforehand, when the images are taken. Shit in, shit out. Bad images when shooting cannot be improved during editing, at least it will represent a lot of wasted work. » So, in Japanese “ Shit in, shit out ” also applies to several principles, including espresso.

Even if at home you are equipped with a La Marzocco and a Malkhonig ProM, the entry of a bad coffee into the chain will only give you what the coffee can give. Because the equipment only expresses the aromas of the coffee.

Choose fresh roasted coffee , preferably within 2 weeks. This detail is sometimes difficult to know because many roasters hesitate to put the roasting dates on the bag. But as this criterion becomes a consumer requirement, many adapt and display it on packaging, including Brûlerie du Quai.

I would also say to be open to the idea of ​​taste profile, terroir and trying lighter roasts. We often confuse the notion of “espresso grain” with the espresso preparation method. In theory, you can use any coffee bean to make espresso. The result will then be an expression of the chosen grain. So there is no espresso bean, there are only coffees that have been blended to obtain a specific taste profile. And according to my philosophy, a coffee blend should include 3 to 5 coffee origins maximum.

Macinadosatore – The dosing mill

The mill is essential. So you need a mill. It must be millstoned. Leave the wings for the spices. Only a burr grinder splits the coffee beans evenly and allows for correct extraction. And be aware that conical type grinding wheels perform better than flat grinding wheels.

It is partly the grind which will determine the extraction rate. The finer the grind, the thinner and tighter the flow will be. The coarser it is, the faster the flow will be . The goal here is to achieve a flow rate of around 1ml per second, to have a beautiful crema, a honeyed, creamy texture enhanced with “tiger stripping” during extraction.

Once your grinder is properly adjusted, grind the coffee one cup at a time . The coffee grinder with the grain size of espresso promotes the evaporation and rapid drying of the aromatic oils contained in the coffee. So for espresso, grind the coffee no more than 15 minutes before preparation .

The coffee bean must be broken into particles in order to be able to extract the solid and soluble components.

Why is such a fine grind required?

• To erode or wash away a large amount of particles from as much coffee bean chip surface as possible;
• To break as many particles as possible in order to release the greatest number of soluble particles which will be transferred to the liquid;
• Allows the coffee to be packed into a denser and more uniform cake, which larger particles do not allow. Small coffee particles are easier to pack, thus clumping together into a dense mass.

The performance of the mill is crucial. A poor quality grinder under heavy use will heat the grounds, produce more dust and give uneven distribution of grounds in the portafilter. No espresso machine, even with all the optimal characteristics, can compensate for poor quality grinding.

The grinder is often the most overlooked element by new business operators, due to the price of a good grinder, preferring to invest in a more impressive espresso machine. The quality of the grinder is therefore a major element in the preparation of an espresso.

A good mill:

• Produces a uniform grind using standard or ideally conical (bimodal or trimodal) burrs;
• Is easily adjustable;
• Do not heat the coffee during grinding;
• Limits dust production;
• Has a good engine, quite strong and well ventilated;
• Allows the replacement of grinding wheels when they are worn (worn grinding wheels create dust, which modifies extraction)

Mano – The hand, the barista technique

Once the coffee has been chosen and ground, all that remains is to dose it into your filter holder and tamp it using a “tamper”.

The tamping step is essentially used to eliminate spaces inside the ground coffee, create a uniform cake and smooth the surface. Tamping also allows the barista to obtain information on the sensation offered by the grind, its distribution and the quantity of coffee in the filter holder.

The force applied to pack the grinds is less important than the adjustment of the grinds, and is the source of several erroneous information. The difference in the cup between light and forceful tamping is minimal. Once the cake is formed using the tamper, tamping more or less firmly will not significantly change the water flow.

• The majority of the pressure put on the grind with the tamper will be eliminated during the pre-infusion when the coffee is humidified.
• The 35-50lbs of pressure exerted by the arm is ridiculous compared to the pressure that will be put by the machine during extraction. (9 bar = 130.5 psi; 58mm portafilter (area = 4.09 sq in) 130.5 psi x 4.09 sq inc = 533.7 lbs)

It is best to adjust the grinder to a grind that will be lightly packed, allowing baristas of different sizes to operate without constantly adjusting the grinder. Too much pressure from the barista will place unnecessary stress on their wrist and shoulder, resulting in possible long-term injuries.

A tamper with the diameter adjusted to its filter holder, an adequate grind, and a light tamping force will facilitate bar operations.

There is also no point lightly hitting the filter holder with your tamper. Several arguments in favor of this step are without proof of their real effectiveness. A well-adjusted tamper will limit the coffee that will stick to the walls of the filter holder. It is these small coffee residues which are targeted by the striking stage. The coffee then falls onto the surface of the cake, forcing the barista to tamp it a second time. Given the force applied by the machine, this coffee is negligible due to its quantity. The strike also risks fracturing the coffee cake, thus creating a channel which will give the water an easy passage and limit the erosion of the overall mass.

Machina – The espresso machine

The purpose of the espresso machine is to send water through the ground coffee in a temperature and pressure profile. We recognize a quality machine when the temperature and pressure are constant with each espresso, even with intensive use. Many machines on the market are unable to achieve a stable profile, mainly due to a mechanical design similar to machines invented in the 1950s.

The number of kettles, the system used to control the water temperature (PID), the digital controller allowing you to adjust the parameters are characteristics allowing you to optimize and control the use of your machine.

If the machine is defective or poorly adjusted, your espresso will be of poor quality. However, this is perhaps the most reliable setting of the 4 and even with an entry-level residential machine, you will be able to get a decent espresso if the above settings are mastered.

And that’s it for the 4Ms of espresso

So, if you are a real one, and you are not afraid to face the 4Ms, you will be fully rewarded by obtaining a rich and aromatic cup. You will also have access to a very dynamic and unifying fraternity around your favorite beverage. Because this beverage will remain difficult to master, and you will end up falling into an alchemical trance worthy of Colonel Aureliano Buendia. On the other hand, you will end up emerging from solitude and inevitably meeting another espresso alchemist ready to exchange their secrets and techniques so that you too can turn the coffee bean into gold.

Danny Marquis