To achieve a good coffee roast you have to start with beans that have been skillfully selected and dried.
Some bean processors use a wash to remove the fleshy fruit from the bean and to separate different kinds of beans. Density differences in the bean will cause some to float higher, making for easier removal or separation.
Others use a slower, more expensive dry-process.
Dry-processed beans will have a more subtle acid profile, while the acidity of wet-processed beans is more striking. Some acidity in coffee is desirable. The alternative is a flat, lifeless cup.
What happens to beans as they heat up during roasting?
During the process aromatics and acids, along with other flavor compounds, are produced in varying concentrations.
During the first stage the beans absorb heat and the green beans are slowly dried to a yellowish tinge. ‘Green’ doesn’t refer to the color, per se, but simply to the beans being unroasted or raw. Properly done, the beans will have an odor reminiscent of toast or popcorn.
From about 170°C-200°C (338°F-392°F) sugars in the bean will begin to caramelize, aided by the increase in temperature of the moisture enclosed by the skin. That’s just one reason it’s important that beans have the proper moisture content, which comes from correct drying. Caramelized sugars are less sweet, so reaching the proper amount is important for the final brew.
At about 205°C (400°F), beans will expand to about double their original size and become light brown, simultaneously losing about 5% of their original weight. As the temperature rises to about 220°C (428°F), beans will lose about 13% more weight and release some CO2.
When the temperature increases to around 230°C (446°F), the roasting beans become medium-dark brown and take on an oily sheen. Often there will be a loud pop as the beans enter the ‘second crack’ phase.
Here roasters have to be very cautious not to overdo it. Volatile aromatic compounds are boiled off and the oils on the outside of the bean can combine with oxygen in the air. That process can strip the bean of desirable flavors and lead to a burnt taste.
The goal is to arrive at just the right balance of bitterness, acidity and a host of other attributes making up the final flavor profile.
In tasting guides coffee connoisseurs will sometimes see the term ‘body’, as if its meaning were self-evident. ‘Body’ despite what it suggests, does NOT refer to the actual thickness or viscosity of the liquid. That attribute is the result of the kinds of proteins and fibers in the brew.
Used as tasters do, it refers to the feel on the tongue when rubbed on the roof of the mouth. It’s the result of the fat content in the drink and that – apart from growing conditions that home roasters can’t control – is determined largely by the roasting.
Too light a roast will leave too high a concentration of bitter compounds in the final product. Too dark will produce an excessively chocolatey, burnt taste. Experiment until you find the balance that suits your taste.
Here is another interesting article about Light Roast Vs Dark Roast Coffee
Whether you are just beginning the journey to your relationship with coffee, or are a coffee aficionado who wants to understand the process more fully, roasting of the coffee bean certainly impacts flavor and intensity of brewed coffee.
What does the roasting process involve? And when it comes to light roast vs dark roast coffee, which will you prefer?
The process of roasting coffee transforms the chemical and physical properties of green coffee beans into roasted coffee products.
Coffee acquires its characteristic flavor by virtue of the roasting process. The green coffee beans expand, and then change in smell, taste, color and density.
A roasted bean has very similar caffeine, protein and acids as an unroasted bean, but it lacks one very critical characteristic…taste.
How is that taste acquired? By the use of heat which causes the chemical reactions that develop and enhance the flavor.
As the bean absorbs heat, the color of the bean changes first to yellow and then to varying shades of brown.
During the later stages of roasting, oils appear on the surface of the bean, making it shiny. This oil is what gives coffee its distinctive aroma and taste.
The roast will continue to darken until it is removed from the heat source.
So again, when discussing light roast vs. dark roast, how is the length of the roasting process going to affect the taste of the brewed coffee?
At lighter roasts, the bean will retain more of its original flavor; the flavors created in the bean by the soil and weather conditions in the location where it was grown.
Some locations where the coffee beans are typically roasted lightly to retain their signature characteristics are regions like Java, Kenya, Hawaiian Kona, and Jamaican Blue Mountain.
As the beans roast for a longer period they darken to a deep brown. The original flavors of the bean are minimized and the flavors created by the roasting process itself become more prevalent.
At darker roasts, the “roast flavor” is so dominant that it can be difficult to distinguish the origin of the beans used in the roast.
In general, lighter roast coffees are sharper and more acidic than the darker roast coffees.
Darker roasts have a fuller flavor.Beans that have been over-roasted will take on a burned, smoky or charcoal flavor.
Also, there is less caffeine in the darker roasted coffees than in the lighter ones. The roast alone doesn’t determine the resulting coffee taste or quality. The origin of the beans makes a big difference.
Now that you have all of that knowledge in your head, here is some more detailed information to help you decide whether it will be light roast vs dark roast for you…or maybe some of both!
Light roast is also called Cinnamon roast, half city or New England roast. It’s flavor is dry, lighter-bodied, higher acidity, with no obvious roast flavor.
Medium roast, also called Full city, American, regular, breakfast, brown. The flavor is dry, sweeter than light roast; more body exhibiting more balance in acid, aroma, and complexity.
Full Roast, also called Dark, High, Viennese, Italian Espresso, Continental. The flavor is slightly shiny, somewhat spicy, heavier body/mouth-feel. The aromas and flavors of dark roast become clearly evident.
So there you have it…light roast coffee vs dark roast coffee. Which will you prefer? Might have to try them all and decide!
Candi Randolph is a coffee lover who enjoys brewing a great tasting, fresh cup of coffee! For more information, about coffee roasts, see Light Roast vs Dark Roast at Perfect-Cup-of-Coffee.com For more great information, help, tips and generally really cool coffee stuff, visit Perfect-Cup-of-Coffee.com
Tags: Aromatic Compounds, Coffee Roast, Flavor Compounds, Gourmet Coffee, Green Beans, Roasting Beans
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