Let’s take a look at some of the most common points of interest going through an Artisan roasters mind when developing a roast recipe for a particular coffee-
—Flavour formation in the roasting process
A complex and interesting flavour profile cannot be created if the potential is not there to begin with. Higher quality, well processed coffees will have this potential. A good artisan roaster will also look to the genetic background and/or reputation of the variety in question and use this information in recipe development.
—Modulating cup characteristics via degradation and formation of various compounds
The degradation of Trigonelline (Bitter) to the derivation of Nicotinic Acid (Clean and sweet) is just one example.
—Acid formation, degradation and preservation
Positive associated acids contribute an important structural component to a coffee. Most of the time, when we talk about positive acids – it’s fruit related. Good acidity gives the coffee liveliness and is essential as an aspect of what makes a coffee great together sweetness, bitterness, mouthfeel, flavours, aromas, etc. It’s getting all of these – in a balance that is unique for each coffee – that will make your cup great. Examplesof positive-associated fruit acids are preformed citric and malic acids. These exist in fairly high concentrations in fresh unroasted coffee. They tend to taper off as the green coffee ages. This is one of the reasons why abiding to seasonality is paramount – the highest quality coffee should be used at an optimal time after the harvest. Commercial roasteries can roast coffees that were harvested much farther from the roasting date as these nuances are less important.
Formation of melanoidans
Melanoidins are brown, high molecular weight heterogeneous polymers that are formed when reducing sugars react with amino acids (constituents of protein) through the Maillard reaction. Melanoidins are commonly present in foods that have undergone some form of non-enzymatic browning such as various baked goods and, of course, Coffee. Because of the high molecular weight of melanoidins, they impart a heavier body and thicker texture to the brew. This is one reason why darker roasted coffees are associated with a bigger body. But Coffee doesn’t necessarily have to be roasted darker for body and mouthfeel to be enhanced. Saying a coffee is dark is merely a reference to the level of sugar caramelization of a given roast and is limited in its classification (this is a topic for another post.)
Sugar preservation and transformation
Caramelised sugar will yield various sweetness associated aroma compounds which we still to some degree experience as sweetness via olfaction (on the nose). Residual sucrose left over and preserved in the coffee after the roasting process ends up being experienced via gustation (in the mouth). A good artisan roaster will know how far they need to go.
The 5 basic taste’s modulation. The balance of the five basic tastes
Sweet, salt, sour, bitter and savoury all exist in coffee and need to be juggled in a way that makes the cup interesting and tasty. This juggling act changes depending on the Coffee being roasted.
There are many more points that will make a difference in profile development, and sadly, there are roasters out there that don’t even consider the few mentioned above. Artisan roasters generally have more interest in their work as they know that the potential is there for them to unlock in the first place, allowing for more of a creative playground where maximum self-expression is possible. As with anything else, the raw materials will dictate potential outcomes and Artisan roasters generally have plenty of excellent raw materials.
Until next time.