Dark Roasted Coffee ... Understanding Dark Roast
Dark Roasted Coffee
The profile for dark roasted coffee is notably flavorful
Green coffee beans go through different stages during roasting before becoming a dark roasted coffee. Coffee seeds are the seeds of a fruit from a tropical evergreen shrub called Coffea arabica. When the green beans from these seeds are roasted it turns brown. The roasting process gives dark roasted coffee it's familiar look and brings out it’s deep, rich flavors.
In the first phase of the roasting process, the Mailard reaction begins, a chemical reaction where coffee starts to turn brown. This happens at around 150°C/302°F. During the Maillard reaction, gases including carbon dioxide, and water vapor create an internal pressure. The bean turns pale to tan to light brown.
This event is known as first crack with the increases of carbon dioxide and water vapor pressure causing a break in the cell walls of the beans, making a popping sound. As the roasting continues, the structure of the coffee bean continues to change and melanoids continue to develop. Melanoidins are commonly present in foods that have undergone some browning, such as barley malts, bread crust, bakery products and coffee. As well as changing the color of the beans, they contribute to the final mouthfeel of dark roasted coffee.
There’s a lot of science involved in producing that delicious cup we all love.
The rapid increase in temperature inside each bean during the roasting process transforms the internal moisture content into gasses. When the temperature reaches around 170°C (338°F) long, complex carbohydrate chains begin to break down into hundreds of new, smaller molecules. This phase is known as pyrolysis, or what roasters call caramelization. Chemical reactions caramelization develop the brown color and rich flavor you get when roasting coffee. This reaction will continue throughout the roasting process creating darker colors and different flavors, distinctly unique to that particular coffee bean. And every dark roasted coffee is unique.
“Green coffee beans go through different stages during roasting.”
The Roasting Phases
Whenever we roast dark roast coffee, the green beans go through the roasting process as follows:
1) As the bean begins to heat up, they start to lose the green color- This is the start of the Mailard reaction.
2) Bean begins to lose moisture.
3) Skin ( “chaff” ) starts to turn a brown hue and begins to shed.
4) Initially, a small crackling sound can be heard – This is first crack. Pyrolysis is now occurring and will continue through the second crack. The bean is now twice the size, has shed the majority of its silverskin or chaff.
5) Bean volume goes through changes
6) Second crack starts to appear and chaff is removed from the air process. Full City or Medium roast is at the first signs of the second crack.
7) The bean’s oil start to rise to the surface of the bean – Continuing through the second crack results in Vienna roast, the first level of dark roast
8) Aroma and flavor development continue
9) Continued roasting causes more structural changes and the oil come to the surface -, this results in dark roasted coffee like French and then finally Italian roasts, the darkest.
10) Cooling process – rapidly circulate cool air over the beans. This process ensures that accurate bean temperatures and roast levels are achieved. If beans are not cooled they will continue to bake.
“There’s a lot of science involved in producing that delicious cup we all love”
Dark Roasted Coffees –
We offer three levels of dark roast. The first is Vienna Roast, then French Roast and our darkest is Italian Roast.
The longer a coffee is roasted, the more structural changes occur within the bean. For example, during roasting at high temperatures, volatile compounds such as lipids (oils) migrate to the surface of beans. This helps to weaken cell walls and retain volatile chemicals which are key to creating aroma and flavor for dark roasted coffee.
The oils in coffee are essential to creating the flavor and aroma we all love. Oils are lipids that are produced by the coffee plant and stored in the cell vacuoles. They help keep volatile compounds inside the cell to create a longer-lasting, more complex flavor. The dark roast produces the chemical transformation that brings the oils to the surface of the beans, creating the rich deep flavor which dark roasted coffees are famous for.
Several full-bodied coffee blends have combinations of dark roast.
Dark Roast Blends:
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