The quest for espresso - Volume II

Dany Marquis

Or on Apple podcast: Historical overview

The Quest for Espresso - Volume 2

Coffee is one of those products that is not easy to consume if you want to enjoy it. It is for this reason that the relationship between roasters and consumers is special. It’s truly a special relationship. Unlike a beer that you uncork and immediately taste what the brewer has created, coffee requires you to prepare it. And this preparation requires technique and knowledge of the product. It's still quite simple, but it requires an investment of energy if you really want to taste what coffee has to offer.

Moreover, we notice two strong trends in the industry:

On the one hand, the race for simplification, for immediacy, I would even go so far as to say the infantilization of consumers, with canned coffee, in capsules, with 100% automatic espresso machines, pressurized sleeves, etc.

Moreover, the development of residential machine technologies took place around this point.

Make espresso as simple as possible.

And if you look closely, communications from equipment manufacturers are almost the same as fad diets.

A result worthy of a professional, effortless and hassle for less than $500.

I have to say that this strategy works well, you just have to look at the popularity of capsule machines.

But I can understand that the equation of effort invested vs. result obtained is not interesting for everyone.

It's a bit like baking, making a cake from eggs, flour, butter, making a ganache for creaming, etc., or a Duncan Hines box with 3 eggs and half a cup of oil.

In short, you understand that this is not my camp but I can understand that we sometimes lack time to make a recipe from scratch.

But, I remain a big foodie and for me, the effort will be rewarded.

But to better understand these two major trends, here is a little history.

Where does espresso come from?

In fact, behind every invention there is a problem to solve, or as we say so well in the world of R&D, a technological uncertainty.

Preparing coffee can take a long time. If we want to shorten the contact time, nothing could be simpler, we just have to grind it more finely.

There is, however, a limit and a very fine grind will no longer allow water to pass by gravity at a certain level of particle size, we must give it a boost otherwise the water will stagnate above the grind.

And it is this preparation time which has created the need to prepare coffees more quickly. This desire arrived at the same time as the industrial revolution.

It was in France that the first patents were filed and that we saw the first “on-demand” coffee maker innovations around the 1850s.

Large coffee shops like those found in train stations in large cities were constantly on the lookout for methods to produce coffee faster and on demand. If there are no customers, no pot of coffee sitting on a stove. And if there is a line of 30 people, we will serve them as quickly as possible.

And since we were in the age of the steam locomotive and the use of steam as a solution was current, the idea of ​​using water pushed by steam through a very fine mass of coffee was then put forward.

It was at a time when the fashion for drinking coffee in public establishments was asserting itself, and when speed was becoming the main representation of modernity. Slow methods were considered outdated and from another era.

Manufacturers therefore set out to produce machines capable of meeting the tastes of a clientele in love with speed and instantaneousness.

And the history of the development of espresso coffee makers is punctuated by numerous patents which allow us to trace its evolution over time.

So these were the first machines using technology to push water through a bed of ground coffee that was too fine for gravity to do.

In terms of chemistry, we will speak of an extraction: either extracting a substance present in a solid to pass it into a liquid solvent.

There are other methods to do the same thing: maceration , infusion and decoction technique. These are all solid-liquid extraction methods that can be used to prepare a cup of coffee, which can be experimented with with the filter, full-immersion methods and the many preparation accessories.

But the majority of these methods take time, and what we wanted was to speed up.

So using steam to speed up extraction was a very ingenious technical innovation. And it was faster.

Was the coffee good?


Water that was too hot gave a very bitter coffee with a burnt taste, probably also coming from deficient roasting methods and unsubtle processing of the coffee beans. But we had found a way to speed up the process.

This steam method was used for several years with more or less modifications, because the principle was quite simple.

A heat source that heats water and raises the pressure in a tank, a kettle, with valves to modify the pressure of the kettle, a bit like an autoclave type cooker, or a presto, and another valve that projected the water through the ancestor of the filter holder which contained the ground coffee.

Therefore, we can consider that France was at the origin of this innovation even if we find traces of similar development in Italy with the Bezzera, Pavoni and Victoria Arduino companies.

But this method caused many discontent, because the coffee did not meet the criteria of good taste and finesse that could be found in other beverages and in other areas of gastronomy.

Because as I said in my preamble, we can agree that tastes are in nature, but there are still common cores in terms of good taste.

Steam was a good way to propel water through the coffee mass,

Steam coffee maker explosion

but the pressure was limited. Not to mention the danger of explosion if we wanted to increase it.

In short, we are now moving to Italy.

Always with a view to gaining speed, Giovanni Achille Gaggia registered a patent on September 5, 1938, which would revolutionize the preparation of coffee.

This is why we often associate the invention of espresso with Italy, because what Mr. Gaggia did is actually the basis of modern espresso. While French inventors have rather evolved the percolator.

What Mr. Gaggia did was use a mechanical system, a spring, to increase the pressure.

A lever allowed you to load a cylinder with very hot water and compress the spring, then release the lever and let the spring propel the water through the mass of coffee.

This technique did not really make it possible to speed up the serving or the release of the coffee, but made it possible to use less hot water, and to grind the coffee even finer, which ultimately allowed the extraction of a good best coffee.

And the increase in pressure allowed the appearance of the famous cream, crema in Italian, which gave the drink a different aesthetic.

A small coffee, strong, intense, crowned with a layer of hazelnut-colored cream, that's what charmed us.

Because if the taste of the coffee was improved, the appearance of crema gave the beverage a unique personality.

A bit like the foam head of a beer.

Gaggia lift

Because by increasing the pressure, the water was able to dissolve more of the carbon dioxide present in the coffee after roasting. And when the water, now loaded with soluble and insoluble elements, found itself in the cup without the pressure, the gases dissolved in the water could no longer remain there and rose to the surface to form a layer of small fine bubbles. .

This layer of cream did not appear in previous versions since steam alone did not dissolve the carbon dioxide.

This is also why “moka” type coffee makers, like that of the Bialetti company for example, do not make crema. There is extraction, water is pushed through the coffee mass, but the pressure is insufficient to dissolve the carbon dioxide.

So no cream.

Since it has become a strong marker of its identity, crema has long been considered an ultimate quality factor for an espresso.

In fact the appearance of crema is simply an indicator of sufficient pressure to dissolve the carbon dioxide.

So, from a correct extraction.

Is this an indicator of good taste?

No not at all.

An espresso can be topped with a splendid hazelnut-colored crema and taste like old wet wool.

The presence of crema also makes it possible to determine certain factors such as the freshness of the coffee. A fresh coffee, say less than 1 month after roasting, will have a higher gas content than one that is 6 months old.

And the color of the crema will depend on the origins of the coffee used and especially the level of roasting applied. Darker coffees will make a darker crema, because non-soluble elements, such as very fine dust, will color the crema.

In short, Mr. Gaggia's invention was significant and was the start of a series of developments which lead us to what we have today.

Then, to replace the spring and the cylinder, there was the use of an electric, electromagnetic pump, which is still used today in small residential machines. There have also been numerous patents filed here, but it is with the Faema company that we associate the use of an electric pump to push hot water through the coffee mass.

We are then in 1961, also the date of the invention of the famous E61 group head. Technology still used today to keep your head warm.

In fact, the E61 head involves using water from the kettle to circulate hot water through the head. It's a technology that works well and variations of which are even found on the majority of modern commercial espresso machines.

We are then still using the same principle of propelling hot water over a mass of coffee to extract the soluble and non-soluble elements.

And then we reached a plateau in terms of the acceleration of the extraction process.

The race to go faster having ended, the emphasis on the taste of the beverage then took over.

How to control the settings to get the best possible brew?

And we started to innovate on the control side.

For example, controlling water pressure and temperature with the addition of a thermocouple type temperature probe.

Or the use of a pressure switch and a heat exchanger to evolve towards multi-kettle machines using PID (proportional, integral, derivative) regulators connected to microcontrollers.

And for dosage, we went from a simple timer connected to the pump, to physical volumetric calculators in the groups, and to feedback systems using scales to ensure ratios are respected.

And of the famous E61 group, several variants were created and high quality machines now use what is called a saturated group.

The innovations that followed mainly concerned the desire to control and optimize the extraction parameters in order to improve the taste.

Decent espresso

The evolution of technologies, electronics, and computing brings us today to highly configurable machines like those I use here, the La Marzocco Strada, or in the laboratory the Decent DE1XL.

And following the preamble to the first episode, I told myself that situating the evolution of espresso over time could guide the vision you have of the beverage and also understand where you are in your quest.

Are you looking for speed? The simplicity?

Or you want the ultimate tasting experience with perfect control of settings.

And therein lies the compromise.

Because today, the search for speed makes it possible to obtain a better quality espresso than those produced in 1910.

The speed and simplicity of a 100% automatic machine with an integrated grinder, or even the manual one with a pressurized handle, will not allow optimal extraction of a great vintage of coffee. You will therefore have to stay in what I call experience coffees, more raw, with a very coarse profile.

This is the same principle with capsule coffee systems.

Your quest is therefore based on this compromise and this compromise will be influenced by the choice of equipment, and by the same token, by the budget you want to devote to it.

Because certain equipment, despite what manufacturers may say, will not allow you to make an espresso worthy of a professional coffee bar operated by competent baristas.

However, whether you decide to follow me in the quest for excellence by perfectly adjusting your parameters or whether you keep your current equipment in order to improve your experience as much as possible, understanding coffee extraction will help you. will help to better understand what is happening and what may be influencing your cup.

And better guide your search for equipment.

See you for the next episode.


Volume 3 of The Quest for Espresso is out!

Find it here:

Find volume 1 here:

1 comment

  • Jean-Claude Soulard

    Tjrs aussi pertinent, précis, concis, soucieux du bien et du bon à tirer des grains provenant des pays et continents différents. Appréciable également de prendre le soin de vous lire lentement (je le fais à haute voix) afin de saisir tte la qualité de votre propos et de notre extraction de grains. Merci! Au plaisir de lire la suite-3. J-C. Soulard

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