Roasting: meet Diedra

Makana Garden’s Diedrich IR7 - 

And now for the good stuff. Don’t get me wrong: everything up until this point in incredibly important in aiding for a consistent, flavorful and aromatic experience in the cup.  In roasting, we allow these characteristics in the beans to come alive.  A skilled roaster will hit the intersection between acidity and sweetness, producing a cup that perfectly balances both the origin flavors and the roast profile.

Before I get a bit too poetic about this, I must tell you that this is the most scientific and intuitive phase in the journey of coffee.  A good roaster utilizes both instinct and logic in their approach for the perfect roast.

There are many ways to roast coffee beans.  The most common types include: drum roasters, fluid air bed roasters (similar to popcorn poppers) and stove-top (aka saucepan).  I’ve even come across solar powered roasters!  The most used commercial roasting method is the drum roaster, of which dates back to the 1800’s.  Drum roasting develops a good body, but also tends to mute the brightness (or acidity), if not careful.  Fluid air roasters are absent of direct heat and is touted to create a cleaner cup, but is criticized for it’s simplicity and small batch size.  However, a well trained roaster can create an amazing cup on any type of roaster, given some practice, skill and a highly trained palate to detect differences in flavor.

Why do we roast coffee?

The green coffee bean holds all the acids, proteins and caffeine as a roasted bean, but it lacks the flavor.  Thus, in roasting, heat is applied to trigger chemical reactions which help release the flavors of both the bean’s innate characteristics, and that of the roast profile chosen for that roast.

What happens during a roast?

During the roasting phase, coffee loses 16-20% of it’s weight in moisture.  It actually grows in size, which in turn decreases it’s density.  Oils are released and move to the outer surface of the bean. The color gradually changes, and will be discharged from the roaster once it reaches a desired shade.  As the color changes, it is also expanding in size, growing as it darkens.  Check out these images to see the beans at different phases in the roast cycle.  The most important result of roasting is the creation of detectable flavors and aromas. For more detailed info, check out Coffee Planet’s rundown of what happens.

What is a roast profile?

A roast profile is the recipe that one chooses when roasting a batch of beans.  Here at Makana Gardens, I am learning on a Diedrich IR 7.  For this machine, the heat is applied directly through the drum (powered by propane).  The machine also allows for applying air in varying amounts if desired.  Every thirty seconds, the temperature is noted and then tracked on a graph.  The curve that emerges from this tracking tells a great deal, and allows for repeatability.  Post roast, it is essential to cup a sample to analyze.  If a characteristic (such as acidity or roast flavor) is unbalanced, then the roast will be attempted again until it is reached.  Craft roasting is the process of finding the perfect roast profile to enhance all the positive features, mute the negative ones and be able to repeat it once it’s figured out.

Both Jimmy and I have found a strong passion for this stage of the coffee journey.  We learned back during our time of serving coffee from a cart, that so much of the coffee experience depends on how the coffee is roasted.  There is a reason why many people refuse to drink coffee black.  It’s because it tastes black!  Our experiments roasting at home for our own consumption, expose us to so many more personality traits of coffee.  We have even convinced the committed creme and sugar drinkers to appreciate it pure.  I can’t say that our roasting skills were much of the reason either.  Medium to light roasts speak for themselves, and have so much more to say.

Roasting is extremely sensory, and with every new batch of green bean there is a lesson to be learned.  Jimmy and I are excited to explore, learn and enjoy our experiments. When we nail a particular profile, we will be sure to share.