Lesson 1 of 1: Roasting Coffee

When it comes to roasting coffee there are generally two mindsets.  One believes that roasting coffee is an art and the other believes that roasting coffee is a science.  Liz Roquet embraces both at different times of production. The actual roasting of the coffee is completely scientific.  At certain times and certain temperatures you are guaranteed certain chemical reactions within the beans.  There is no guesswork when it comes to roasting beans.  The true art form, according to Liz, is developing blends of beans that achieve certain flavor profiles for the customer. When it comes to roasting coffee, time and temperature are the main factors in achieving the roast you are looking for.

To imagine the inside of a roasting machine think of a dryer.  A rotating drum is blasted by heat from infrared burners.  This drum is constantly turning to ensure even roasting as well as circulate the air around the beans.  If the drum were to stand still the beans could catch fire.  With a roasting machine you can control the heat and the air.  The more air you let in the hotter it gets due to the increase in oxygen.  It is the roaster's job to nurse the roast and decide the roast degree.  The quality of the beans is controllable, the rate at which they roast is controllable and it is up to the roaster to determine the flavor desired and when to stop the roast.  Coffee is roasted at such high temperatures that even a few seconds difference between stopping a batch could mean you end up with an entirely different roast than what you intended.

During the roasting process the sugars in the coffee beans begin to caramelize.  Based on how long the beans are roasted the sugars can lead to flavors that are sweet, toasty, smoky and burned.  Sugars are very important because they play one of the biggest roles in how the coffee tastes.  As coffee is roasted the volatile oils that give a cup of coffee its flavor come to the surface.  The darker the coffee is roasted the more the oils begin to emerge.  When roasting beans it is key to look for smoothness and sheen.  During the roasting process coffee beans can lose up to 15% of their weight, but increase about 20% in size.      

Before you start to roast coffee you have to have an idea of what flavors you want to highlight and what beans can achieve the final cup you are looking for.  Blending different types of beans can create an experience that, as Liz puts it, "doesn't happen in nature and complements the flavors you want, whether they are fruity, earthy, zingy or just a base".

The three main keys to a great cup of coffee are:
1. Top Quality Beans
2. An Attentive Roasting Process
3. The Freshness of Roasted Beans

 To the Right: A fresh batch coming out of the roaster.

 Liz Roquet's Diedrich Roaster

A range of beans at different levels of roasting.  In the distance are un-roasted green beans.  Next are light roasted, then medium-light, then medium, medium-dark, and then dark roasted beans.