Ever wondered what goes on behind the scenes in the coffee roastery, shaping the flavor profiles that ultimately become the coffee blends that you enjoy each morning? Today, we're delving into the captivating world where the science of roasting and the art of blending converge, resulting in that perfect brew we all crave. To truly understand the process behind how some of your favorite blends are created, we will first need to learn a little more about the intricacies of the roasting process — a delicate balance of temperature, time, and expertise. Then, we will talk about some of the basic theory behind why a roaster would choose specific coffees and techniques for a blend. Finally, we will discuss some of the most common blends, from the light and bright Breakfast Blend to the dark and bold French Roast.
Before we can even begin discussing the process of roasting coffee, we need to talk a little about the coffee bean itself. As many of you are undoubtedly aware, the coffee bean is actually the seed of the coffee plant. What you may not be aware is that prior to roasting, the overall flavor of that coffee bean has already been influenced by many factors, including the species of coffee, what country and region the coffee was grown, the altitude and climate of that particular region, and the soil composition of the specific farm. All of this adds up to a lot of different variables that the roaster has to account for and address as part of the roasting and blending process.
After being imported, the beans reach the capable (hopefully) hands of a roaster, whose job it is to transform those green, vegetal beans into the blends that we consume every day. Roasters have 3 main levers that they can manipulate in order to determine the outcome of the roast; temperature, time, and airflow (there are a few other factors, such as drum speed that do impact the roast, but are not as frequently batch to batch by the roaster). The first decision the roaster must make is the Charge Temperature. Like preheating your oven, the roaster sets a target temperature at which to begin the roasting process. The actual mechanism to do so changes slightly depending on the type of roaster being used, but the theory stays the same. Once the green beans are introduced into the roaster and throughout the remainder of the roast, the roaster controls variations in temperature, inducing chemical reactions that culminate in the development of the nuanced tasting notes we associate with a well-roasted coffee.
The element of time also plays a crucial role in the roasting process, and, in tandem with temperature and airflow, helps to influence the development of the entire roast. The duration of roasting impacts the depth, richness, and complexity of the final product. Too short a time may result in underdeveloped flavors and leave the coffee tasting grassy or vegetal, while an extended roast could lead to the emergence of bold, smoky and bitter notes. Finally, manipulation of airflow can be used to help manage temperature by introducing cool air into the roaster. In addition, air movement also helps separate the chaff, or parchment layer, from the bean and move it to a section of the roaster called the chaff collector. Lastly, airflow can introduce a new form of heating called convection. Unlike conduction heating where the beans are heated by contacting the hot metal surface of the drum of the roaster, convection roasts the beans by the heated air that surrounds them.
Ok, so now that we are through all of the technical roasty mumbo jumbo, we can finally talk about blends. Before we get too involved on the topic, I do need to preface by saying that there really is no once size fits all when it comes to blends. Every roaster will have their own methods for developing blends, but it usually comes down to a couple of different variables. First is the availability of beans. One of the beautiful things about blending beans is that it allows a roaster to have a smaller quantity of different origins of beans while still offering customers a wide variety of different flavor profiles. This makes it appealing to roasters just starting out who want to offer a several different initial offerings, but cannot afford the investment of buying several different large bags of green coffee.
Secondly, blending allows a roaster to tailor a coffee for consistency within a specific flavor profile that may not be as well suited for a single origin coffee. For instance, you see most of the larger scale, commercial brands selling blends because it allows them to offer customers a consistent product throughout the year, when a specific single origin may only be available seasonally. As we discussed earlier, due to changes in flavor imparted by various factors, it is rare that you can substitute one single origin for another and get a similar product unless it was from the same producer in the same region and processed using the same method.
Finally, a huge consideration when blending is cost. Roasters are able to combine higher grade coffees with not-as-high grade coffees to produce a nice, balanced middle of the road blend at a lower overall price point. The primary consideration here for roasters is to ensure that they are not being misleading by claiming that a blend is a single origin and charging a higher price to receive higher margins.
Now that we understand some background around why roasters blend, let’s talk about my specific approach as a roaster to blending. My methodology for developing a blend varies slightly depending on the specific coffee that I am working on. For example, let’s assume that a wholesale customer approaches me and asks to develop a blend similar to another coffee that they have had in the past and enjoyed. This is a very common request, and it is a challenge that I will enthusiastically take on. When I sit down to start thinking about the coffee, I am by no means attempting to directly copy another brands blend (nor could I without knowing the exact source of their beans, their roasting curves, and many other various information that I am extremely unlikely to have). Instead, I want to take the essence of that coffee and then make it something of my own. I start by cupping (or tasting) the reference coffee if possible. This will give me the best starting point by letting me take my own notes on the coffee and give me a starting point that I can return to eventually with my own samples. Once I have an idea of the attributes that I am pursuing, I will try to find a match with coffees that I have in stock. I know the coffees that we stock very well as I taste many of them on a daily basis, so I use that knowledge to build a preliminary blend recipe. Personally, I usually start with as few different coffees as possible and then build from there. Typically, I aim to have no more than 3 or 4 different beans in each blend as adding more usually just muddles the end result.
Once the preliminary blend is in place, I begin sample roasting. I usually start with the different origins evenly divided into the blend on the first sample roast. In other words, if I was using 3 different beans, I would use a mixture 33% of each bean within the batch. The first sample roast usually gives me a good idea of if I am on track with my initial planning or not. If I am on track, I can now tweak the recipe by either adjusting the amount of each origin in the blend, by adding or subtracting an origin, or by roasting longer or shorter to make the roast darker or lighter. If I am really off, I can always start back over with a new strategy. After every sample roast, it is very important to taste samples against the reference coffee to make sure you stay in calibration with the goal. I continue to adjust the sample roasts until I arrive at a blend that fits what the customer is requesting while also meeting the standards of our roastery.
Similarly, if I am creating a blend for myself to use with our customers without any external input, I usually already have a plan in place in my head for what I am looking for. All this means is that I can skip the step of cupping a reference coffee and start with sample roasting some of our coffees that we keep in stock and tasting those against my plan for the blend. I recently was working on a blend that was to become our Donut Shop medium roast coffee. For this blend, I wanted something that was appealing to as broad of a customer base as possible, as Donut Shop blends are staple offerings for coffee roasters around the world. My vision was a coffee that was full bodied and rich in flavor, but that was not overly complex. Often, the more complex tasting notes can be polarizing and are not a great fit for a more utilitarian use coffee. Also, a major consideration for this coffee was cost. As it is going to be used primarily for our office delivery service, I want to ensure that the price point is able to be maintained at a level that our customers expect. Therefore, I carefully selected several beans that I thought would fit the requirements and, after several rounds of sample roasting and tasting, I decided on a simple two bean blend of a washed Guatemalan and a natural Brazilian. The result was exactly what I was looking for, full bodied with a chocolate base and earthy notes with low acidity sweetness, and bitterness.
Before we wrap up, I also wanted to mention some of the most popular blends that you will see online and in stores.
· Breakfast Blend - usually a light roast, medium bodied coffee (although I have seen some companies use this name with a medium roast). Often, this blend consists of Central and South American beans and, if roasted well and consumed fresh, has some mild fruity sweetness and acidity. As its name suggests, this blend is usually intended to be consumed in the morning with food.
· Donut Shop – a medium roast, full bodied coffee. Again, this blend usually consists of Central and South American beans, Donut Shop is usually a very popular blend with customers looking for a middle of the road coffee for everyday drinking.
· French Roast – a dark roast, full bodied coffee. Usually with heavy roast and smoke flavors, the beans used in a French Roast can be sourced from any of the coffee producing countries. Typically, lower cost beans from South America or Southeast Asia make up the bulk of this coffee. As a lot of the nuance is lost as the beans roast darker, lower cost options are usually used in dark roast coffees as opposed to medium or light roasts.
· Espresso Blend – We have a full article on espresso blends. Please see use click here if you would like to read more on this topic.
And there you have it! Science and art combined into one to form the prefect blend to help start your day or to use as an afternoon pick-me-up. I hope after reading this article that you can now appreciate the thought and attention that goes into selecting the right coffee to include in a specific blend. Now the only thing left to do is get out and start trying some new coffee!
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