The Guide to “City” Roast Levels. The terms City, Full City, French Roast, etc. have been long used in the coffee domain to refer to roast degrees, but they have never enjoyed universal specification or agreement on what exactly each term meant. For this reason, we don’t normally refer to roast levels in these terms in our lab, as we find they are too limiting. Instead, we mainly use our Mill47 Lab Card and related color spectrometer readings (Agtron values) to quantify our roast level. You’ll notice the terms on our Lab Card are more descriptive and are becoming more common.
But, since these legacy terms are still tossed around in the coffee space, it’s important to understand what they are, what they imply, and how they can help communicate information about the degree of roast. Below is a general description of these terms correlated with a specific Agtron number/value.
City. City roast coffees are those that are dropped during or just after first crack. These are your typical “light roast coffees” which are usually more acidic with a more mild body. Lots of coffees we roast, especially the Kenya Kiamabara that we drink daily, we roast to this degree. While this range is generally our personal preference, not all beans and origins are well-suited for city roasts. Desired internal temperature for city roasts is around 390-400°F. Agtron #70
City Plus. If city roasts are the light roasts, city plus is the crossroads between light and medium. These roasts typically have a bit more body, slightly less acidity, and slightly darker color. The desired internal temperature for city+ is around 400-410°F. Agtron #60
Full City. Full city roasts are a classic medium roast. These coffees typically display more body, moderate acidity and accentuate notes of ripe fruit and caramel. They are often crowd pleasers and can be good for a french press or components for espresso blends. The desired internal temperature for full city beans is around 420°F. Agtron #50
Full City Plus. Full city plus roasts are proper dark roast coffees. You’ve heard us complain about dark roasts before, but certain beans are well-suited for darker roasts. We wouldn’t normally aim for full city +, but we encourage you to experiment and roast to your preferences. After all, that’s what it’s all about. Full city plus roasts are usually roasted to an internal temperature of around 430°F. Agtron #40
Vienna / French / Italian / Spanish Roasts. While full city plus is a roast degree that we agree with and support with certain beans, these darkest styles are not recommended. Again, these terms are subjective and often vague, so a lighter French/Italian roast may be palatable, the darker editions chemically destroy the beans, reducing them to ash and carbon. Body, acidity and any flavor/aroma traits have been reduced to smoke. Agtron #25 - #35
Keep in mind that, in general, during first crack the beans are expanding and developing. During second crack, the basic structure of the coffee is beginning to decay and collapse. In this later phase, oils begin to accumulate on the beans, leading to an acrid brew and, if left unchecked, risk of roaster fire!