Roasting vs. Brewing - What's the Difference?
Let's Get This Out Of The WayNow, for the obvious answer. Roasting is the process of applying heat to the coffee beans prior to grinding and brewing. Brewing is the process of running hot water through coffee grounds in order to make a drinkable beverage. Easy, right? Is that everything, though? Not really.
Okay, yes, technically the answer is that simple. Roasting the coffee beans happens before grinding and brewing them into that mouthwatering morning elixir. So, what are we talking about? How would anyone be confused as to the differences between these two actions?
It's all in what they impart when applied to the beans.
Roasting green coffee beans is an art. The reason coffee beans are roasted is to enhance (or sometimes hide) the natural flavors found in those yummy beans. The roasting process is measured by the degree of darkness. Light, medium-light, medium, medium-dark, and dark are all the typical levels of roasting.
The lighter the roast level on a coffee, the more of those natural flavors that you can taste. A coffee bean that has been lightly roasted still retains much of its natural flavor. Fruity notes of stonefruits like peaches, berries like strawberries or cherries, and citrus fruits like grapefruit or lime can be found in light to medium-light roasted coffees. These flavors may be nuanced but the lighter roast can help to draw them out without being overbearing.
The darker the roast level on a coffee, the less of the natural flavors that you can taste. More of the roasted flavors will be noticeable. These flavors include spiciness (like cinnamon), nuttiness, caramel, chocolate, and more.
In other words, the process of roasting coffee beans determines their flavor.
On the other hand, during the brewing process, the act of pouring hot water over roasted and ground coffee beans determines the amount of caffeine in your cup. The longer water is in contact with the surface of the coffee beans, the more caffeine that is produced.
The process of brewing coffee is a balancing act. If water is in contact with the grounds too long, the coffee can taste bitter. However, if water is in contact with the grounds for an insufficient amount of time, the coffee can taste sour.
We've talked before about brewing coffee and how to avoid the pitfalls. But to summarize in the context of caffeine absorption, if you want more caffeine in your cup, you need to have more water touch more of the surface of the beans. The brewing process allows that to happen, not the roasting process.
Don't They Both Do Both?
You COULD argue that both steps provide both outcomes, but truly, that is only because they work hand-in-hand to provide the beverage we drink.
The roasting process CAN affect the amount of caffeine in a negligible way--the darker the roast, the less caffeine in the coffee. Some argue that caffeine is "burned off" while others contend the volume of the beans has been lowered. But that's a discussion for another day.
On the other hand, the brewing process CAN affect the flavor of the coffee. But is over or under extraction really a flavor? Not really. They're more flaws in the resulting drink. Therefore, we'll stand by the statement that roasting affects the flavor of your coffee while brewing affects the caffeine content.