UK Barista Championship finalist and senior barista at WatchHouse, Evangelos Koulougousidis, chats to Imogen Phillips about the purpose of crema and its future in the world of espresso brewing.

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From the sound of the boiler forcing water towards the grouphead, to the swirling streams of thick, syrupy coffee pouring out of the filter, brewing espresso is akin to an art.

And, once in the cup, the espresso has one final trick: the crema, a mesmerising tan-coloured foam that settles on the surface of espresso straight after brewing.

Chemically speaking, crema is formed by excess gas which, no longer able to be held by the liquid espresso, is released to form a light foam.

Essentially, it’s a raft of tiny bubbles created when hot water emulsifies the soluble oils present in coffee, and as such, some coffees produce more crema than others.

For example, robusta, a naturally oilier coffee, often produces more of a velvety, distinctive crema than espresso extracted from arabica.

Evangelos Koulougousidis is Senior Barista at WatchHouse in Tower Bridge, London. His background in mathematics impacts his attitude to coffee, allowing him to perceive through the lens of science.

“The topic of crema hasn’t been researched extensively by scientists,” he explains.

He recalls a quote from a 1989 research paper by M. Petracco, who found that when there is an absence of crema, “some bitterness and astringency can be perceived”.

For years, many coffee professionals have held many such beliefs regarding crema, with some maintaining that it’s a good indicator of espresso quality.

However, modern coffee experts assert that a velvety, thick, layer of crema isn’t an absolute sign of coffee quality at all. In fact, this association may have come about because of the perceived superiority of espresso over filter coffee.

In the specialty coffee industry, this is known to be a misconception, as different brewing techniques have their own pros and cons. Ultimately, however, crema is an inevitable byproduct of the espresso extraction process. But does that make it essential?

How can crema contribute to espresso’s characteristics?

When drinking espresso straight, crema makes up much of the first sip. As such, it leaves a prominent first impression, which is why the “perfect” crema should be pleasing, creating a soft mouthfeel. Over the years, this first impression has reinforced the perceived importance of good crema.

“When serving espresso to customers, there is the impression that the thicker the crema on the espresso, the heavier the body of the espresso is,” Evangelos says. “This verifies the fact that first you ‘eat with your eyes’.”

He explains that this “perfect” crema should be smooth and have a fine balance between acidity and sweetness. In many cases, crema may taste bitterer than the espresso beneath it, leading some people to advocate for stirring the crema into the coffee. In theory, this ensures that all the flavour profiles are combined and can be tasted in each sip.

Aside from taste, mouthfeel, and body, Evangelos says, crema acts as a barrier that prevents volatile aromatic compounds from escaping the cup, while also keeping the espresso hotter for longer.

Over time, the thin film forming each bubble – known as the lamella – loses stability and collapses, ultimately exposing the coffee below along with all its aroma compounds. This typically occurs two to three minutes after brewing.

For a barista, this is useful, as it gives them time to get the drink to the customer while it’s still hot and before the inevitable “aroma burst”.

However, it’s crucial to note that in an industry where darker roasts are no longer held as the be-all and end-all of coffee, the role of crema may be diminishing.

“Different species as well as lighter roasts have been introduced, making us more open minded on how things look, while paying more attention to the flavours of the coffees,” Evangelos adds.

Is it really necessary?

Regardless of changes in coffee preferences and the impact of crema on espresso characteristics, one thing is indisputable: crema is essential to latte art, and subsequently, it remains a necessary aspect of espresso brewing.

According to Tasmin Grant, barista and managing editor at Perfect Daily Grind, crema helps to create a contrast between the espresso and the milk, making designs look sharper and cleaner.

“The crema is like the canvas for latte art,” she continues. “I would assume the tiny air bubbles and oils in the crema help to support the microfoam as you’re pouring, which helps to create latte art.”

Aside from its role in latte art, however, crema has perhaps been historically overvalued as an indicator of the quality of espresso. This has had significant repercussions for the coffee industry, leading many consumers to believe that crema is incredibly desirable or that it’s a sign of a good barista.

The net result is that for many coffee shops and cafés, crema is still absolutely necessary, if only to satisfy these misconceptions.

Nevertheless, as the range of available coffees and their corresponding roast levels and flavours have diversified, it’s possible that less emphasis will be placed on crema going forward, especially if baristas play an active role in consumer education.

“That doesn’t mean that the crema of the espresso doesn’t play a role in the drinking experience at all,” Evangelos notes, adding that customers may instead begin to acknowledge that the presence of perfect crema doesn’t guarantee delicious tasting coffee.

Rather, they’ll recognise that a coffee roasted darkly enough will still create a beautiful crema, but that this all comes down to extraction and personal preference – and not the quality of the coffee.

That being said, Evangelos asserts that baristas should continue to stay abreast of crema techniques and trends and use the best equipment available.

“If a coffee always produces a thick and luscious crema, but for some reason the espressos are coming out with thinner crema that isn’t lasting as much as it should, we might need to look deeper into it,” he explains.

“This might come from a change in the roasting process, a fault in our coffee equipment, or we might even need to polish our espresso making technique.”