When we buy a bag of roasted specialty coffee, often we see the words “light”, “medium”, and “dark” used to describe the roast profile. However, some roasters may not provide a profile at all, instead just offering an “espresso roast” and a “filter roast”. 

While the difference between a filter and espresso roast can be as simple as the former being lighter and the latter being darker, this is not always the case. Although espresso roasts are generally darker, some people still want to be able to taste the acidity in their cup, and choose light or medium roasts as a result. Conversely, some coffee drinkers prefer to use darker roasts for filter coffee.

To learn more about how to roast at home for filter and espresso, I spoke to Evan Gilman at Royal Coffee. Read on to see what he said.

Lee este artículo en español Cómo Tostar en Casa Café Para Filtro y Para Espresso

The Rise Of Home Roasting

Between the growth of specialty coffee and global lockdowns as a result of Covid-19, it doesn’t look like home roasting is going anywhere.

Today, budding home roasters have easier access to specialty grade green coffee than ever before. Furthermore, home roasting equipment is more affordable and accessible than ever. 

As a result, green coffee suppliers are adapting to this growing demand by offering smaller quantities for home roasters. 

As well as being an educator for Royal Coffee, Evan is an experienced roaster (both in and out of home). He notes that Royal have seen even more demand in recent months for smaller and smaller quantities – and have adapted to offer the “Crown Jewels”, a range of 1lb (453g) bags.

Evan’s number-one piece of advice for any home roaster – whether they’re roasting for filter or espresso – is to “embrace failure”.

“Not every roast is going to come out perfect. In fact, no roast will ever be perfect,” he tells me. “That’s half the fun. Always improving means never reaching perfection.” 

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Basic Differences Between Roasting For Filter & Espresso

The first thing to acknowledge with roasting for different brewing methods is that personal preference will differ from person to person. Some people will want bitterness in their filter coffee, while others will look for complexity and acidity in their espresso.

Today, many modern roasters simply aim to “unlock the full potential” of a bean, and instead let the consumer decide how they want to brew their coffee. This means moving away from more traditional terminology like “filter roast” and “espresso roast” and instead just providing the roast level (light, medium, dark, or somewhere in between) on their packaging.

“This is a huge area of contention,” Evan explains. “Among professional roasters, you’ll hear about roasting for solubility or for different attributes of the coffee. 

“Many people use the phrase ‘omni-roasting’ to denote a roast that could be used for either filter or espresso. This is a roast which simply tries to bring out the best in the coffee, regardless of the situation. Currently, this is a popular method for roasting.”

However, as much as the “omni roast” is popular among specialty coffee drinkers today (especially those who brew more coffee at home), there are still those who want a bit more direction.  

Evan says: “In older schools of thought, roasters would tend to ‘bake out’ espresso roasts in order to mute the acidity in the coffee.” 

And how do you achieve this? Evan says that that “baking out” is accomplished by “stalling the rate of rise and allowing the coffee to dwell in the roaster for some time, ideally after first crack”.

However, Evan adds that today, “baked” flavours in coffee are considered to be a “sensory roast defect”. He says that the flavours associated with baked coffee are “muted acidity, a lack of sugar development, and a generally stale flavour”. 

“The idea is that baking a coffee will lead to a smoother espresso,” he adds. “However, you have to remember that roasting is a reductive process. The longer the coffee stays in the roaster, the more you are taking away from it.”

Consider The Coffee’s Origin

As Evan says: roasting for too long “takes away” from the coffee. But what does this mean? Well, the darker you roast your coffee, the more you mute and hide the origin characteristics which are present in the green coffee. 

In the specialty coffee world, many people believe that lighter roasts showcase the “full potential” of the green coffee and highlight how and where it was grown. So, are there certain origins or countries which grow coffee that is best suited to espresso or filter?

Evan notes that while certain flavour profiles might be more appealing for certain brewing methods, it’s not as simple as dividing origins into two distinct categories. “While different types of coffee tend to work better for different [brewing methods], I don’t think this is true across an entire origin.”

He tells me about some of the traditional examples: “Brazilian coffees have (traditionally) been used for espresso blends because they often have a mellow and sweet character. Ethiopian naturals have traditionally been used sparingly in both espresso and drip blends to add a deeper, fruity flavour, but were generally not accepted as a single-origin filter.” 

However, things are changing. With the emergence and growth of third-wave coffee in recent years, more and more people look for brighter or “funkier” coffees that offer new and unfamiliar flavour notes. This means looking at more specific traits, such as variety, processing, and various other parts of a coffee’s terroir.

Choosing to roast a coffee a certain way based only on its origin is reductive. The more information you have about a coffee, the better equipped you will be to roast it. Evan adds that origin shouldn’t be a way to categorise or profile coffees, but rather something that should help us gain a deeper appreciation of the coffee world. 

“Each origin produces a wide range of coffees,” he says. “Half the fun is in exploring, finding what you like, and deciding how you like to brew each coffee you come across. They’re all unique.”

Light, Medium, And Dark: What’s The Difference?

This is one of the most argued points in coffee roasting. Many coffee drinkers across the world have become accustomed to drinking dark roasts, with all the bitterness and intensity they offer. Conversely, specialty and third-wave coffee champion light and medium roasts as being more delicate and subtle.

Lighter roasts are roasted for a shorter period of time, and use more heat during the process to reach first crack (which occurs at 196°C/385°F) more quickly. The aim is to “seal in” the natural acidity of the bean, resulting in a brighter cup. However, lighter roasts will generally lack the body that a longer, darker roast will produce.

Medium roasts generally occur between the end of first crack and the beginning of second crack (between 210°C/410°F and 220°C/428°F). These will have slightly muted acidity, and will preserve some of the coffee’s origin characteristics, but the flavour from roasting will be noticeable.

Medium-dark roasts begin around the beginning or middle of second crack (225°C/437°F to 230°C/446°F), while the end of second crack (240°C/464°F) is when we start to get dark roasts. Coffee is generally not roasted beyond 250°C/482°F, at which point it will begin tasting of charcoal or tar. 

As coffee is roasted to second crack and beyond, its body will increase, and it will become bitter and smoky. It will also start to lose its recognisable origin characteristics and acidity. 

So, when roasting for filter espresso at home, what should you do? Well, firstly, you need to consider which flavours you want in your cup, rather than which flavours historically suit a particular brewing method.

For instance, if you want acidity, subtlety, and to showcase more of the origin, go for a lighter roast. Similarly, if you want bitter and smoky flavours in your coffee, a dark roast will be more suitable. 

Either can be used for filter or espresso; just remember that espresso will be brewed with less water, and therefore offer a more concentrated flavour and a heavier mouthfeel.

Evan says: “Higher priced coffees might fit better for lighter [or filter] roasts. You’re paying more for the nuanced acidity, gentle aromatic qualities, and deep sweetness of a high quality coffee. 

“Roasting to darker levels will only subdue the acidity, remove inherent aromatics in favour of the flavours of the roasting process, and eventually carbonise sugars past the point at which they caramelise.”

Data Is Important: Keep Records & Educate Yourself

Today, in commercial roasteries, computer software and spreadsheets will often hold years’ worth of data. Having access to the minor details of previous seasonal coffee lots can sometimes hold the key to fine-tuning a roast profile.

Evan recommends doing something similar throughout your home roasting journey. “Take notes for every roast! You won’t believe how valuable these will be for your future roasts, whether or not you’re roasting with the same coffee or on the same machine,” he says.

“The more rigorous notes you take, the more you’ll start to notice patterns emerging in your roasting and the coffees you use.”

However, education is just as important. One of Evan’s biggest tips for aspiring roasters: “Read as much as possible.

“It can be fun to reinvent the wheel [and do things slowly]. However, if you want results right away, the best way to get them is to look at all the information you have at your fingertips.”

He adds that Royal have created an online learning platform for aspiring roasters and coffee professionals. The Crown is an open-source coffee education centre based in Oakland, California. As well as hosting a “tasting room”, it also operates online classes and hosts podcasts.

“At The Crown, we analyse many of our offerings, look at different brew methods for different coffees and publish our findings and recommendations online,” Evan says.

Roasting at home is a great way to experiment with origins and flavour profiles you might not have considered before. The rise of home roasting and the increasing availability of small quantities of green coffee just means there are more opportunities than ever to experiment.

And while having a brewing method in mind might help you dial in your roast, it’s important to understand that the ideal “filter roast” and “espresso roast” will differ from person to person. Rather than roasting dark for espresso by default, consider what you look for in your cup. Think about what’s important to you when brewing with a certain method, and roast to your taste.

Enjoyed this? Then read The Rise Of Home Coffee Roasting

Photo credits: Ana Valencia, Neil Soque, Evan Gilman

Please note: Royal Coffee is a sponsor of Perfect Daily Grind. 

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