A complete guide to roasting coffee for espresso

Matteo Pavoni
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October 29, 2021
espresso

Today, many roasters roast their coffees according to specific brew methods. Not only does this help customers choose coffees that suit their home setup, it also provides a clearer picture than descriptors such as “strength”.

Coffees intended for moka pots and espresso machines generally fall under the category of “espresso roasts”.

Characterised by their solubility and rich, intense flavours, espresso roasts are designed to complement a brewing process that involves using high pressures and small volumes of water. The aim is to create a highly concentrated and full-bodied brew that pairs well with milk.

Although roasting for espresso relies largely on the green beans themselves, there are a few important factors to consider for those who want to produce the best results in the cup.

To find out more about roasting for espresso, I spoke with Cofinet’s relationship manager, Bethany Williams.

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espresso vs filter roast
Extraction is predominantly what sets filter coffees (left) and espresso coffees (right) apart

Why are espresso and filter coffees roasted differently?

Coffee brewing methods fall into two broad categories: filter and espresso.

While there are a number of differences between them, extraction is the most significant attribute that sets them apart – specifically total dissolved solids (TDS).

TDS refers to the soluble parts of roasted and ground coffee that are dissolved and extracted by hot water.

Filter coffees – made by pouring hot water over grounds – tends to have an optimum TDS of around 1.2%, while espresso is considerably higher at 7-10%.

Indeed, in The Coffee Dictionary, coffee expert Maxwell Colonna-Dashwood says that any coffee below 7% “starts to become something else”. He writes: “It may well be great – but it just isn’t espresso.”

“Ideally, we’d look for sweetness, balance, and body in espresso…”

Therefore, to achieve a higher TDS with a short extraction time, the beans will need to be developed for longer during a roasting phase, as this generally produces more solubles.

With a light roast, the resulting solubles may not be enough to hit the optimum TDS, leaving the coffee tasting “flat” in the cup.

Bethany has been in the specialty coffee sector for years, working as head roaster at Colonna Coffee, among other positions.

She says she would always roast for filter or espresso in order to highlight the best of the coffee’s flavours for various brewing methods.

“We wanted to differentiate between filter and espresso roasts because the brew method is different,” she tells me. “Espresso goes through higher pressure and higher extraction, so you don’t want those acidic, upfront notes to be the predominant character making the cup unbalanced.

“Ideally, we’d look for sweetness, balance, and body in espresso, while still enhancing the acidity. Whereas for filter, we’d highlight those more subtle floral and bright characteristics that will shine in a brew.”

espresso roast
Espresso roasts usually require a longer development time than filter roasts

How to roast for espresso

Bringing out a coffee’s best characteristics in the cup relies on a number of factors, from grind size to water temperature.

However, a large part of the responsibility ultimately rests on the shoulders of the roaster and their ability to roast in a way that complements each brewing method.

For espresso, Bethany explains that tasting each coffee and tweaking the roast accordingly is key.

“It’s always good to have a baseline approach when roasting for espresso and then being able to make adjustments depending on the coffee,” she says.

“So let’s say I’d always have in mind a certain roast time and development – for example, nine minutes and 18% development. I can roast in this way and taste the coffee to see how it’s turned out.

“If it’s overdeveloped or I’ve missed out any characteristics, I can go back and try to roast faster, for example eight minutes.

“It’s always good to have a baseline approach when roasting for espresso…”

“It’s basically about adjusting development, roast time, and temperature based on your assessment of flavour and balance.”

This is particularly important when it comes to acidity. Espresso brews tend to produce more acidity in the cup because the high temperature and pressure of the water used extracts more of the chlorogenic acid found in coffee.

To balance this out, roasters generally extend the development time for espresso roasts. This allows more time for compounds in the beans to break down and caramelise, leading to a sweeter coffee with more muted acidity.

It also helps bring more oils to the surface, creating the highly prized “crema” – a thin layer of creamy foam – when hot water emulsifies the oils.

However, Bethany tells me that development time is only one aspect. Roasters also need to factor in charge temperature and roast curve.

“For a filter roast, we’d normally start with a hotter charge temperature and end with a lower temperature,” she says. “It would also be a faster roast.”

“For an espresso roast, on the other hand, we want a longer development, so we have a lower charge temperature and end with a higher end temperature, giving an overall shallower curve.”

espresso
Sweetness, body, and crema are all important considerations when roasting for espresso

Espresso & milk: Roasting for lattes, cappuccinos, and flat whites

Despite the immense popularity of espresso in countries like Italy, its most widespread use is as a base for drinks such as cappuccinos, lattes, macchiatos, and flat whites.

According to the National Coffee Association, cappuccinos and lattes represent two-thirds of all coffee orders in the US.

As such, it’s important to consider how well espresso roasts will complement the addition of milk when it comes to roasting. This means approaching the coffee with body, sweetness, and intensity in mind, as this will help it stand out while complementing the milk.

Similar to balancing acidity, this typically involves extending development time beyond first crack, giving chemicals in the coffee’s structure time to caramelise.

However, the choice of coffee also plays an important role. Flavour notes such as chocolate, nut, and raisin tend to pair better with milk than floral or fruity flavour notes, for example – but these can’t be brought out by roasting alone.

The origin, processing method, and growing conditions, among others, impart distinct characteristics on the coffee. Therefore, it’s up to the green bean buyer (who is, in many cases, the roaster) to select coffees they think will form a good espresso base.

recyclable coffee bags
High-barrier coffee bags with degassing valves are key to preserving the freshness of espresso roasts

Most roasters offer a mix of espresso and filter coffees to appeal to different corners of the market. While some may prefer the typically delicate and acidic qualities of filter coffees, others favour the rich, sweetness that espresso coffees offer, particularly when paired with milk.

For both roasts, you’ll need to ensure your packaging not only tells customers what to expect from the coffee, but also preserves its freshness.

At MTPak Coffee, we offer a range of sustainable coffee bags that can be fitted with degassing valves and resealable zippers. Our multilayer packaging offers protection from oxygen, heat, moisture, and light, while also showcasing a commitment to the environment.

For information on our eco-friendly coffee bags, contact our team.

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A complete guide to roasting coffee for espresso

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