Weโve been on an extended Ask Lee break, mostly because there have not been too many questions but I received a great one this week: are all your coffees light roasts? And the answer is both yes and no. The roast degrees of light, medium, and dark exist in a bigger pool of terms for roast degrees, including Vienna, Cinnamon, City, French, City Plus, Full City, and so on. The list reads like a confusing mix of places, spices, or actual references to gradients. So, where do the dividing lines between a light or dark roast actually exist?
Coffee roasting can be very simple. Toss a handful of green beans into an air popper or cast-iron pan and they quickly morph into recognizable brown beans. Here is one of those taste is subjective disclaimers, but the process is straightforward, as heat and time transform a raw bean into its brew-able form. The โroast degreeโ in this sense is: the longer you cook, the darker and more โdevelopedโ the bean. It is a rare steak versus a well-done steak moving from a light roast to a dark roast.
There are some technical approaches to roast degrees. The industry standardized scale is called the โAgtron Color Classification Systemโ. It uses an infrared spectrometer to shine an ultraviolet beam through a coffee sample to determine a level of reflection. The result is a number between 0 and 100 with lower numbers indicating a darker roast. It is pricey but quite effective in terms of results. If you read through a lot of coffee research, you will see three other main approaches with either total roast time (Baggenstoss, Poisson, et al, 2008), final bean temperature (Laukalฤja and Kruma, 2018), water loss (Yearger, Batali, et al, 2022) or some combination of all the above (Fabbri, Cevoli, et al. 2011) being the determinate for roast degree.
The problem these industry and academic specific approaches illuminate (spectrometer pun) is in translating these values outwards to those buying and brewing coffee. Saying, โI like light roastsโ is not quite the same as โplease, give me a bag of Agtron 95+โ or โa coffee with less than 13% water loss, pleaseโ. This is partially why there was a slew of terms created, be it Full City or Vienna. Without keen parameters, like a 0-100 scale, these can be โcreativelyโ applied. I certainly have sought out light roasts and ended up with burnt beans.
So what is the solution, or to repeat the question, what is a light, medium or dark roast? One of the easiest ways to frame roast degrees is around โFirst Crackโ. It is a literal description for the point in a roast where the momentum of heat switches from inward to outward, increasing the release of moisture and gases in the beans. Think corn exploding into popcorn, as an endothermic process converts to an exothermic process with the release of steam. It makes an audible sound, hence the name, First Crack! Now a couple disclaimers: it is less dramatic than popcorn, as there is no explosion, just a slight increase in moisture and gas release. AND, a lot of moisture is released prior to this point, it is just slightly heightened during first crack. AND only about 10-15% of all beans actually โcrackโ (Abbott, 2023).
It marks the end of the โMaillard phaseโ and the start of the โDevelopment Phaseโ. I do not want to put the dry in โDrying Phaseโ here, so the important take away is this: as we approach first crack, reactions between amino acids and reducing sugars help foster the flavour compounds that shape the final cup (Moreira, Nunes, Domingues, et al, 2012) and we reach a drinkable cup! In other words, we are at the start of the roast degree continuum with a light roast! As we push past โfirst crackโ, we move from light to medium with dark roast sitting in the distant horizon.
Because batch sizes, machine capacity, burner power, and the green coffee itself vary so greatly from roaster-to-roaster, there are no strict rules but there are some general tendencies in this light to medium terrain. First, at this end of the spectrum, a cup will have higher acidity. Take for example, a Nordic style with the batch dropped as โfirst crackโ occurs. It will be filled with lots of crisp and bright notes. Second, as โFirst Crackโ rattles onward, we typically get more caramelized notes with higher perceived sweetness. A really great light to medium, will be balanced with acidity present but alongside many of those flavours we associate with fruity sugars. Third, the longer we go, the more body increases in the cup. This is really the fun zone for roasting with an array of citrus, fruit, berry, cooked sugars, and baked goods arising and dropping out of the profile. It is when all those unique notes of origin really shine!
Looming at the end of the โDevelopment Phaseโ is Second Crackโ. As โcarbon dioxide buildup exceeds the strength of the cellulosic wallsโ, the beans shatter (Wang, 2012). If โFirst Crackโ marks the starting line of our roast degrees, this is the end point. But more crucially, it is a point of no return in terms of flavour variation. Any sensory variance in the cup dramatically decreases due to the โdestruction of organic acidsโ including โcitric, malic, lactic, pyruvic, and acetic acidsโ, as well as the production of phenols, which give the coffee โsmoky and asphalt-likeโ qualities (Wang & Lim, 2014; Handayani, 2016).
Roasting this dark fundamentally changes coffee in multiple ways, especially when compared to the slight distinctions between light to medium. First, because of the destruction of acids and creation of phenols, you experience the elements of roasting itself. The cup tastes of carbonization, charring, and burnt caramelization regardless of origin or processing. Second, the extent of cellular degradation allows oils to escape, resulting in that oily and slick surface you might notice in a dark roast. These exposed lipids are susceptible to oxidation (Taci, et al, 2013) and prone to going rancid (Budryn, et al, 2012). Which relates to the third key difference: shelf life. We went deep in a past post (Ask Lee: On Aging Coffee) but the takeaway is both light and medium roasts benefit from rest, whereas the flavours of dark roasts decline rapidly.
At Quietly, I donโt traverse the smoky post-Second Crack landscape but I do maintain my โdrink what you likeโ mantra. While it is undeniable that roasting to second crack changes the structural, chemical, and sensory elements, you get a style of coffee that is easy to achieve and reproduce. The bitter flavours take dairy and sugar well and works great as a base for all kinds of flavoured drinks. I understand the appeal and the point I am making here is not that dark roasts are inherently bad, but rather, we tend to approach light to dark as a continuum, despite the intense and forceful rupture of Second Crack. It is not a linear progression but rather a decisive break.
Given the long history of dark roasts and their ongoing ubiquity in coffee, it makes sense that we have a number of terms to parcel out degrees, like Italian or Vienna or French. For all these pre-โSecond Crackโ coffees, the traditional term was either โBlondโ or โCity/City Plusโ but in most contemporary coffee marketing, companies rely on terms like โbrightโ or โโvibrantโ or โlivelyโ or even โexpressiveโ to describe roast degree. You will see lots of talk of โacidityโ but it comes with a complete avoidance of any โsourโ talk. This new coffee lexicon, while sunny and roseate, is a little opaque for outsiders. Much like โboldโ and โstrongโ, โbright and โvibrantโ have become somewhat hollow and empty given their mass adaptation and incessant repetition.
Their widespread use is part of the searching for a better way to talk about light and medium roast degrees, which is not as technical as the Agtron scale nor as wide-reaching as โLightโ. Complicating matters is that unlike a dark roast, which is reflective of the roast process itself (that uniform array of smoke and char), any roast in that light to medium realm is going to be varied in sensory attributes and the elements specific to origin. A lightly roasted naturally processed Guji and Nariรฑo Pacamara are going to present drastically different in the cup, making any overarching term tough. Moreover, there is a lot of bad batches in that light to medium realm: baked, flat, underdeveloped, bitter, vegetal, spicy, and often unbalanced with sharp sourness โฆ sorry, sharp acidity. A dark roast covers up mistakes but there is no where to hide in the light.
In theory, we could have a large set of โlight roastโ coffees which have a similar final temperature, or weight loss, or reflective gradient of brown, but in practice, they could have wholly different taste profiles due to the elements of origin dovetailing with individual roaster approach! Until we have a better vocabulary, which will be tough, we have roaster specific standards. And given the fact we are working with an organic product in a near endless set of conditions, we thus rely on these vague terms like โbrightโ or โlivelyโ.
With all our background work done, to the question: are all of Quietly roasts light? Given the moving markers, they are light compared to a lot of coffee in the world. However, they do spend some time in the roaster following first crack meaning they are not as light as some contemporary roasters. When a new coffee arrives at HQ, I do a number of test batches to find a balanced โend pointโ. Seeking balance between perceived sourness, sweetness, and bitterness, the perfect batch will unlock a full array of the unique notes tied to terroir and be pleasant to drink. Not coincidentally, this means light to medium roasts.
The big dividing line we use and, perhaps, the most useful when buying coffee is โEspressoโ vs โFilterโ. By design espresso machines use pressure to extract, while filter brewers use gravity (and or agitation), so the former often concentrates flavour notes. Our espresso roasts for Allie & Lennie, Magnolia, and Shady Lane often have less acidity than those filter roasts, as it will balance in the end cup. Plus, pushing a roast slightly makes it more soluble (see the breaking cellulosic walls detailed above), which translates to easier to dial-in on the bar! I really regret using little icons on our bags, because they are easy to miss and often confusing. Most of my โhelp me brewโ emails are due to brewing delicate pour-overs with one our espresso roasts and it always makes me wince, because I know their cup would be vastly improved had they snagged a filter specific bag.
Espresso and filter are not perfect however, as they too suffer from that roaster-specific application. They do remain useful because it is a direct appeal: when you get home, use this machine or this brewer to get a great cup. Equally, terms like โlightโ or โmediumโ have merit by virtue of the explicit connection to the bean. It is the literal colour of the beanโs surface. With terms like โbrightโ the link is a little more ambiguous, as it comes through an individual sensory experience and is always going to be subjective. You might recall the post on taste notes (Ask Lee: The Tyranny of Taste Notes) and it remains tricky terrain because everyone lives in their own world of sour or sweet or bitter. โVibrantโ or โlivelyโ are accordingly much more abstract markers compared to actual gradient colour or a suggested preparation.
Such terminology confusion illuminates one of the bigger problems in coffee. If a key goal is to turn more people away from commodity coffee towards specialty (with the ensuing consequences of paying producers more and helping push commodity crops to specialty level), we need clarity. Instead, we often rely on well for lack of a better term โexpressivenessโ. Indeed, third wave coffee required a rethinking and revolution of existing approaches, pay structures, roasting rulesets, and sensory understanding but we continue to always rage against the old machine without actually building and working in the current moment. A set of roast terms, which are clear and easily understood, would be one small part of that puzzle in which we can escape confusion and industry gatekeeping.
For now, I want to put filter and espresso clearly on our next bag design and continue to roast coffee that is versatile enough to work in any brewing context. However, when asked this question, I will also probably continue to shrug a bit and say โlight-mediumโ is the roast degree but the real important part is the story of the people, the place, and the labour behind the bean, which will always speak in clear terms through the wonderous sensory experience of each and every cup.
Works Cited
Abbott. โItโs not what its cracked up to beโ. Barista Hustle: Research and Articles. (2023).
Baggenstoss, Poisson, et al. โCoffee roasting and aroma formation: application of different time-temperature conditionsโ. Journal of Agricultural and Food Chemistry. 56, 14 (2008): 5836-3846.
Budryn, Graลผyna et al. โInfluence of roasting conditions on fatty acids and oxidative changes of Robusta coffee oilโ . European Journal of Lipid Science and Technology. 114 (2012): 1052-1061.
Fabbri, Cevoli, et al. โNumerical modeling of heat and mass transfer during coffee roasting processโ. Journal of Food Engineering. 105 (2011): 264-269.
Handayani. โCoffee and Its Flavorโ. Jurnal Ilmiah Rekayasa Pertanian. 4, 1 (2016): 222โ217.
Laukalฤja & Kruma. โQuality of specialty coffee: balance between aroma, flavour and biologically active compound composition: reviewโ. Conference: Research for Rural Development. (2018): 240-247.
Moreira, Nunes, Domingues, et al, โCoffee melanoidins: structures, mechanisms of formation and potential health impactsโ. Food and Function. 3 (2012): 903-915.
Toci, Aline. โChanges in triacylglycerols and free fatty acids composition during storage of roasted coffeeโ. LWT โ Food Science and Technology. 50, 2 (2013): 581-590.
Yeager, Batali, Lim, et al. โRoast level and brew temperature significantly affect the color of brewed coffeeโ. Journal of Food Studies. 87 (2022): 1837-1850.
Wang. โPhysicochemical Changes of Coffee Beans During Roastingโ. Master of Science Thesis, The University of Guelph. (2012).
Wang & Lim. โEffect of Roasting Conditions on Carbon Dioxide Degassing Behavior in Coffeeโ. Food Research International. 61 (2014): 61.
Lee Knuttila 