The 5 Senses: An Introduction to Roasting

 

In our three decade of experience with roasting, we have come across so many different ways of explaining the roast of coffee to our patrons. The question is: what do these roasts and titles really mean?

When roasting, the beans lose moisture, and therefore lose weight. The longer you roast, the more moisture and weight is lost. In the pre-roasting process, we weigh the coffee before and after roasting, and take notes of the percentage loss. Generally, single digit weight loss percentage is equated to lighter roasts, while weight loss of 15% and higher results in darker roasts. This method has made our roasting procedure more consistent and informative, especially later on when we cup and taste coffees side-by-side.

At times, oil will appear when roasting certain coffees, but other times the oil will not appear until hours later. You will risk over-roasting the beans if you go by the sight of oily beans alone. It is advisable to use all five senses when roasting coffee. Below is a short summary of what you will be looking for in each of the senses.

Feel

Measuring the temperature and density of the beans before roasting will help you determine the initial temperature and moisture level of the beans. This may be done using various instruments, like a food-grade infrared thermometer to measure bean temperatures, and the Shore Moisture Tester to measure bean density. Over time, your collected data on roasted beans will assist you in determining ideal roasting temperatures for certain coffee densities.

(Refer to our previous article for more information on bean density and Split Bean Analysis.)

Sight

Try to observe the beans as they roast. Sometimes temperatures and moisture can change depending on the variables of the day or season, consequently, causing your coffee to roast differently. When you observe the color and look of the beans, you will be able to establish a baseline of how beans normally roast, and therefore recognizing when they behave differently.

Smell

Pay attention to the scents that develop while roasting. As coffee roasts, it goes through an interesting process; different chemicals that naturally occur in coffee beans change as they reach different temperatures, causing different aromas and fragrances to develop. As the roast progresses, you will observe a wide range of smells. From grassy and earthy to bread and baked goods odors. Additionally, utilizing your olfactory senses can alert you to any signs of fire developing. This is a common concern for every roaster, to keep their roasting facility from setting ablaze, and avoiding loss of life and resources.

Sound

Keep an active ear out for cracking sounds, and other sounds that may occur during the roasting process. The first and second crack during roasting can be very close together, so it is vital to pay attention as to not get distracted and produce over-roasted beans. Additionally, the roaster may make abnormal sounds that you have never heard before, so it is advisable to be familiar with the hums and reverberations of your roaster.

Taste

Taste may be used in the last phase of roasting, often making it the most rewarding part of roasting, as you get to taste the results of your creation. Ideally, we want to conduct multiple tastings or cupping sessions of the roasted coffee. We cup as soon as the beans have cooled down out of the roaster, 24 hours, 48 hours, and 72 hours later. This gives us an objective position from which to judge the coffee and allow for flavor and aromatic changes that often occur within the first few days after roasting. In the end, some coffees may develop their full flavor profile a few days after roasting, while others may develop ten days or more later. Ultimately, the ideal flavor is up to the judgment of the drinker. There are no rights or wrongs for liking the taste of one coffee roast over another.