When you think about espresso, what’s the first thing that comes to mind? For many, the answer will be the crema – the enticing, red-brown foam sitting atop any beautifully made espresso.
This guide will examine what crema is and why it’s present in espresso. It will also investigate whether it is a good or bad element of espresso and whether you should keep or remove the crema before you drink your beverage.
How Espresso Crema Came About
In 1948, Achille Gaggia, the founder of Italian coffee machine manufacturer Gaggia, invented a pioneering piston (or lever) based espresso machine. The machine was unique because it could brew at far higher pressures than alternative brewing methods. However, that high pressure left a layer of strange, caramel-colored foam on the top of the espresso.
To begin with, the foam was unpopular. However, demonstrating a flair for savvy marketing, Gaggia began advertising the foam as the “crema naturale” of coffee. The rest is history – the foam gained acceptability, and Gaggia marketed itself as the brand that gave coffee crema to the world. Crema is now not only accepted but required of authentic espresso.
How Is Crema Formed?
Crema originates during the roasting process. When you roast fresh coffee, it creates carbon dioxide (CO2) as a necessary by-product of the bean’s reaction as it turns brown.
The CO2 is trapped in the fresh coffee bean, and the roasted bean still contains plenty of CO2 when you’re ready to grind it and brew your coffee. Next, you tamp the finely ground coffee and add them to your modern espresso machine before pulling a beautiful espresso shot. Hot water enters the filter basket and reaches the coffee puck. But why does crema appear in the espresso?
Water with nine bars of pressure emulsifies fresh oils from coffee beans and dissolves more CO2 into it. However, when the water leaves the filter basket, it moves into an atmospheric environment from a pressurized one. In other words, there is no longer pressure on the coffee. This means the water can no longer hold the CO2, so it is released as tiny bubbles that constitute espresso crema.
What Makes Crema So Important And Special In Espresso?
Crema is one of the first things coffee experts look for in an authentic espresso shot. But is it that important?
The first thing to note is that crema is a tell-tale part of authentic espresso. It’s so ubiquitous with high-quality espresso that you wouldn’t expect espresso without it.
Meanwhile, the caramel color is undeniably appealing, and the creamy texture elevates the mouthfeel of the shot.
The color has its origins in a couple of elements. It’s mainly related to the color of the liquid beneath it. So, the darker the roast, the darker your coffee – and the crema – will be.
Crema Is A Visual Feedback Of Your Espresso Shots
Crema acts as a piece of visual feedback on the nature and quality of your shot. How the crema looks doesn’t definitively tell you whether the espresso beneath it is high or low quality. However, it does indicate whether you have brewed the coffee at a slow enough pace for a satisfyingly dense crema.
You can look at it from the opposite angle, too – if your espresso doesn’t have crema, it is a sure sign that something hasn’t worked.
Understanding what a crema’s appearance means to the overall quality of the espresso is a skill that experienced baristas possess. An experienced barista in a coffee shop can distinguish over-extraction and under-extraction by the crema in the resulting cup.
Does Crema Affect The Espresso Flavor?
We now know that crema is an important – even vital – element of espresso. However, does it affect the taste?
Most coffee lovers would argue crema improves espresso’s flavor. However, in reality, this is open to debate in the coffee world. Some coffee experts don’t believe the flavor is enhanced by crema, and others go even further, suggesting you’re better off skimming off the crema before you consume your beverage.
If you pull an espresso shot, scoop some crema onto a spoon and sample it, you’ll notice it has a bitter, ashy flavor. Therefore, it follows that if you remove the crema, your espresso will be sweeter and less bitter.
So, which would you prefer? The most accurate way to determine this is to pull two shots using the same beans, grind size, and espresso machine. Then, remove the crema from one and try both shots so you can make a fair comparison. The chances are you’ll find they have surprisingly distinct mouthfeels and flavors.
With the crema removed, we noticed the beverage was significantly less bitter and had a sweeter taste. However, only you can be the judge as to whether crema improves (or otherwise) the taste of espresso because it is entirely subjective. If nothing else, it is an interesting – and straightforward – experiment.
One misconception is that more pronounced crema automatically means the perfect espresso, but that’s not the case. Indeed, you might find a fantastic shot of espresso that has far less crema. There are many factors that affect the quality of your espresso shots, check out our espresso brewing guide if you want to learn more about making espresso at home.
What Affects The Quantity Of Crema?
If you desire and enjoy the sight of rich crema sitting on an espresso, it’s worth learning what causes one espresso to have thicker crema than another. Then you will know how to increase crema in espresso. The following are all factors in determining how much crema an espresso shot has.
The fresher the roast, the more crema the espresso will have. As we explained earlier, crema is produced by CO2. Freshly roasted coffee beans are still gassing and contain more CO2 than pre-roast beans. However, while the crema content tells us how fresh the beans are, it doesn’t automatically make it a better drink. Indeed, many professional baristas prefer to let espresso beans rest for between one and four weeks after roasting because the CO2 can affect the extraction.
Usually, the darker the roast you use, the more crema your shot will have. That’s because darker roasts produce more coffee oils and CO2 than lighter roasts.
However, this doesn’t mean you need to use a very dark roasted coffee to achieve a thick crema. Some espresso beans have the optimum level of natural oils and dark roast degree to produce gorgeous crema. Some single-origin espresso with lighter crema and lighter body also satisfies coffee lovers.
Robusta Or Arabica Beans?
You may notice that many espresso blends contain Coffea robusta.
One of the reasons for this is that Robusta beans tend to cost less than Arabica beans. Another is that Robusta beans have lower acidity and a higher body. However, crucially, Robusta beans also produce more crema.
Studies demonstrate that Robusta beans have a higher CO2 content than Arabica beans after roasting . Meanwhile, they also have fewer lipids and fats.
To helo you understand how this affects the crema content, you can draw a parallel with baking. If you’re mixing egg whites, they will be less foamy if you add an egg yolk to them. The reason? Egg yolks are fatty, which results in less stable foam. In espresso, the more lipid content there is in the coffee, the less stable the foam will be. Therefore, Robusta beans produce thicker crema.
Type Of Filter Basket
Some filter baskets are pressurized, while some are non-pressurized.
Less expensive espresso machines use pressurized filter baskets to produce “fake” crema by forcing the coffee through a narrow hole. However, the resulting crema has a bubble-like consistency because of aeration rather than extraction process. This is why beginners can often achieve a bubbly crema regardless of grind size.
One example of a machine that produces bubbly crema rather than crema produced via extraction is the Nespresso Vertuo. In fact, that espresso machine produces too much crema through agitation, sometimes it’s too plentiful for a regular coffee.
In contrast, non-pressurized filter baskets brew directly into your cup, meaning you’re in command of the brewing process. If done correctly, you can achieve a dense, creamy crema with this type of filter basket.
Often, you might come across discussion of tiger flecking (or tiger striping) shots. These “tiger” stripes usually appear when you use a medium-dark or dark roast in a bottomless portafilter for a shot.
The flecks in question are small particles of coffee grounds that have left the basket and landed in the foam. However, while the flavor should not be affected, many people love them as they look beautiful and add to the appeal of the espresso.
Espresso is a drink to be savored for more than just its aroma and taste. The appearance of the espresso is another important factor in our appreciation of the beverage. Indeed, a beautiful-looking crema represents a significant part of that overall espresso’s appeal.
After all, entry-level espresso machines, including Nespresso, are built to give you some approximation of crema via agitation or pressurized portafilters. Therefore, the manufacturers are aware of the visual appeal of crema, and a good crema is generally expected on an authentic espresso.
However, even though crema is beautiful, you don’t need to force the issue. More crema doesn’t necessarily mean it’s a better espresso, and, as this article has shown, several factors determine the amount of crema an espresso has.
Generally, when brewing espresso, what determines the drink’s quality are factors including the beans you use, your brewing technique, and correct extraction. The best crema is the result of the overall brewing process. However, when it’s such a beautiful addition to espresso, there’s little wonder so many coffee lovers consider it an essential part of a top-quality shot,
 Understanding the Formation of CO2 and Its Degassing Behaviours in Coffee – By Xiuju Wang – https://atrium.lib.uoguelph.ca/xmlui/bitstream/handle/10214/8152/Wang_Xiuju_201405-PhD.pdf?isAllowed=y&sequence=2