The craft of coffee - Part 2: Science and experimentation | PDD

The craft of coffee – Part 2: Science and experimentation

By Marko

on May 8 2024

The second part of our coffee series looks at how science and technology have allowed professional coffee makers to fully understand the volatile process of making the perfect cup of coffee, tuning machinery and techniques to get the best out of the coffee bean.

The last decade has seen a boom in number of new devices and tools used to prepare quality coffee, as well as the revival of old methods. The common theme has been processes that do not rely on pressure – gentle, patient brewing to extract delicate, subtle aromas and flavours. And there are a lot of these: Hario V60, Clever Dripper, Kalita Wave, Chemex, AeroPress, French Press, Espro Press, Syphon Brewing… The list goes on – and that’s not even mentioning any of the products on Kickstarter and similar websites which grow daily.

But it is espresso – the most intense, the moodiest, and teenage-like of all preparation methods that always captures the attention and best encapsulates the current state of specialty coffee. Simply put, espresso is coffee making on a knife edge. High temperatures, high pressures and little time give very small room for error and a slight change in any of the variables can turn a proverbial elixir into poison. This fine balance of science, art and ‘voodoo’ is what makes it so captivating from both a consumption and brewing perspective.

Traditionally Italian-style dark roasted coffee represented espresso: powerful, often bitter and full of caffeine kick, they would usually feature a healthy proportion of the less sought-after but hardier (and therefore commercially viable) Robusta coffee species. The drink was invented in Italy to energise working people on the go rather than something that would be savoured and analysed. In the mornings, the kick would be dampened with the addition of milk for a softer start to the day with one’s pastry and newspaper – hence the existence of the Cappuccino and its milk based relatives (and no, don’t order them after 11am when you’re in Italy…).

These days the increasing use of lighter, Arabica coffees for espresso has opened up numerous flavour and aroma dimensions but also made that knife edge even more perilous (Arabica is the more flavoursome but lower yielding and disease susceptible of the two coffee species).

The respected UK roaster, HasBean, sells an espresso blend called Jabberwocky inspired by the fierce creature from Lewis Carroll’s poem. It typifies the current approach to espresso: “this blend should challenge the palate and not be an easy option, needing hard work to get the best from it. Get it wrong and it will have claws that catch and jaws that bite, but your rewards for slaying this blend shall be plentiful.”

However, science and technology have allowed professionals to fully understand this volatile process, tuning machinery and techniques to get the best out of the raw materials. Modern espresso machines have increasing levels of technical complexity to offer more control and stability to the barista – tuneable brew temperatures controlled by multiple microprocessors, adjustable pressure profiles, integrated weighing scales that work to 0.1grams – all designed to minimise guess work and extract exactly the flavour that is desired – and as the roaster intended.

Analysis equipment that would have been the preserve of laboratories a decade ago is now not only attainable, but pocketable for on the spot coffee forensics. Paired with a smartphone, the VST refractometer allows the barista to precisely analyse their coffee and adjust the brewing variables to obtain the flavour that they want. Many agree that we are now in the midst of the “fourth wave” where the industry is driven to new heights by a scientific approach, much like avant-garde restaurant cuisine and “new cookery” did over the last few decades (just don’t call it molecular gastronomy).

And this approach isn’t solely the preserve of professionals. Coffee aficionados have long relied on the stability and control of commercial equipment at home to achieve that ultimate or “god shot” but the technology to facilitate this control and experimentation in our own environments is becoming more accessible and more usable. Australian home appliance manufacturer Breville and its Dual Boiler Espresso machine for example, allows the user to precisely control the temperature, volumes and pre-infusion pressure to brew the perfect cup. As an interesting aside, Breville markets this machine under the Sage: By Heston Blumenthal” brand in the UK.

The latest buzz in the industry surrounds the current darling of the speciality coffee world – a seemingly rather unglamorous grinder which has been around for decades. Manufactured by the German company Mahlkönig, the EK-43 was originally designed to grind very high volumes of coffee and spices for large distributors and warehouses. However, enterprising and visionary baristas have re-appropriated its use as they have discovered that this tank-like piece of industrial machinery can grind coffee in such a refined and consistent manner (consistency = control = good coffee) that it has redefined the pinnacle of espresso. When used correctly, the grinder allows baristas to create espressos with some 20-30% more of the coffee solids and oils extracted from the beans than average (around 20% is common, with the EK-43 24% is consistently achieved). The difference in flavour is appreciable –sweet, rich, multi-dimensional coffee that simply cannot be made with other equipment.

The EK-43 has also allowed cafes to start using their espresso machines in unintended and un-envisaged ways to brew lighter style coffees that were the preserve of the more gentle methods mentioned before, but generally commercially unviable because of the time and effort needed to prepare the drinks. A completely new drink called a “coffee shot” has been developed that allows cafes to serve filter style coffees with far more efficiency and control and thereby offer the consumer even more choice.

A few percent here and there might not seem ground-breaking, but there is a more important aspect to these advancements when we consider the bigger issues at hand. Rising global temperatures have dramatically impacted coffee production over the last few years. All of the coffee-producing countries of Central America, for example, have experienced drops in production of 30% or more in each of the past two years, and the general consensus is that this unfavourable situation is only likely to get worse. Coffee yields are likely to keep dropping, prices are likely to keep rising, and the cost of what is already an expensive drink will follow this trend. Even more importantly, the livelihood and sheer existence of millions of people involved in the coffee industry around the world is at stake.

We therefore have a need and indeed, duty, to minimise waste of an increasingly precious crop whose success directly impacts the well-being of countless people.

Quality coffee, much like quality design, is a labour of love – from start to finish. And even with the increasing amount of equipment and technology involved, it is fundamentally about people – at the start, at the finish and throughout the process. So, Will and James – thank you, I look forward to my next visit to Mother’s Milk (with my loyalty card in tow of course).

In Part 3 of this series we will have a look at some of the highlights from the London Coffee Festival.