Espresso Machine

Roasting for Espresso – a Home Roaster’s Perspective

While my primary brew method at home is manual pour-over, I supply coffee to my mother and father-in-law, who drink a cappuccino every morning on their prosumer espresso machine (an Expobar Brewtus, which I’ll probably review in a future blog post). In providing coffee to them, I’ve had to learn the nuances of roasting for espresso versus roasting for filter coffee, as well as the differences between roasting for a straight espresso shot and a milk-based drink.

Roast Degree

The first thing that comes to mind when roasting for espresso is that you must roast DARK. This is a very common misconception, especially amongst the general public, as most of the espresso that I’ve enjoyed is NOT a dark roast. However, there is some truth to the fact that good espresso may often be a bit darker than most pour-over coffee. For my pour-over roasts, I’ll typically target stopping right after the end of first crack, which results in a City roast. For me and my roaster, this is typically around two minutes development time, and about 20% development percentage (assuming a typical 10 or 11-minute roast). For espresso, I try to draw this development percentage to around 25%, which typically puts me at a City+ roast, nearing Full City territory. I find that a City roast in an espresso often ends up overly “bright” (acidic) and can have an unpleasant sourness. A medium roast will tend to mellow these bright notes and provide a nice caramel sweetness that is much more pleasant in an espresso.

I’ve done a few experiments with roasting even darker for milk-based drinks, and I’ve found that they DO tend to cut through the milk better. “Darker” for me would mean Full City, maybe 30 seconds of development past 25%. Although roasting darker will work for making espresso that cuts through milk, I think the better method is to use origin and varietal characteristics that better complement milk-based drinks. More on that below. Please note that a darker roast will require more energy at the beginning to avoid the dreaded ROR crash and flick.

Blends vs. Single Origin

10+ years-ago many coffee shops used a blended espresso for most of their drinks, both straight espresso and milk based. In some cases, shops would offer a “specialty” espresso that was intended to be enjoyed by itself, and often offered some unique flavor characteristics that could not be tasted in a milk drink. I’ve found that today it’s much more common for local coffee shops (at least in Houston) to use a single-origin espresso for EVERYTHING. There are some exceptions with the major craft coffee brands who have seasonal espresso blends that have been popular for a decade or more (see Stumptown, Intelligentsia, Vivace). In my opinion, it’s a bit of a shame that espresso blends seem to be going by the wayside. While I love a good single-origin espresso, the reality is that most people at a café will order a cappuccino or a latte. These single-origin flavor characteristics will likely be lost in a milk drink, and in most cases a blended espresso will provide a pleasant balance that cuts through the milk.

The most success that I’ve had with espresso blends has been using a neutral Central American as a base (Guatemala, Colombia, etc.) with a significant percentage (>25%) of dry process South American (Brazil) and a small percentage of an African coffee (<25%). This formula is a little bit different than the “typical” Italian espresso blends, which would often use the dry process Brazilian as the base (>50%). I’ve found that using this much dry process Brazil leads to more earthy/woody flavors than I prefer, especially at medium roast levels. 25% to 40% Brazil still provides a nice viscosity and body without the overpowering earthy/leathery notes. I’ve also found that using a dry processed coffee for the African portion (such as a Harrar or Yirgacheffe) will add body, crema, and acidity to the shot. Trying a honey processed Central American in an espresso blend is next on my list, as I believe the honey processed coffee will provide even better body, sweetness, and crema to the espresso shot.

For straight-shots, I LOVE single-origin coffees. A dry process Ethiopian will turn into a blueberry bomb, a washed Kenyan will be lemony and sweet, and a washed Central American coffee will provide a nice balance of sweetness, acidity, and body. As mentioned previously, these coffees often don’t work as well with milk, as the unique characteristics are quickly lost. An exception may be a washed Bourbon or Caturra coffee, however, I would still challenge roasters to find a single coffee that can cut through milk as well as a blended espresso.

Roast Time

Per the typical guidance, I target espresso roasts to be a bit slower than my filter roasts. A good rule-of-thumb would be 10-12 minutes for a drum roaster. Anything less than 10 minutes tends to be underdeveloped or overly acidic, and over 12 minutes will often creep into the “baked” territory during the development phase. I plan to continue to experiment with changing the length of the dry, malliard, and development phases for espresso. Perhaps that will be a topic for a future post.


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