“I like dark roast because I like my coffee strong” when you hear a statement like this, a true coffee connoisseur will ask “Do you mean in taste or caffeine?”.
It is crucial to discern the difference because quite often people relate to the taste of their coffee to the amount of caffeine. The coffee making process has it that the lighter the roast, the more caffeine it contains.
As coffee beans absorb heat in the roasting process, their color becomes darker, and oils appear on the surface of the beans at higher temperatures. The longer that it is roasted, the more it loses its original flavor and the oil contained. This oil is what contains the caffeine and makes the coffee what it is.
Light roasts are light brown in color, with a light body and no oil on the surface of the beans. Light roasts usually have a toasted grain taste and pronounced acidity. The origin flavors of the bean are retained to a greater extent than in darker roasted coffees. It also retains most of the caffeine from the coffee bean. The problem is that some consumers just don't like light roasted coffee because the taste can be extreme. Too much citrus. Too much floral. Not necessarily balanced.
Light roasted beans generally reach an internal temperature of 180°C – 205°C (356°F – 401°F). At or around 205°C, the beans pop or crack and expand in size.
Medium roasted coffees are medium brown in color and have a good amount of body. They have no oil on the bean surfaces. They are known to exhibit a more balanced flavor, aroma, and acidity. This roast is usually recommended by coffee experts because it is a compromise that often brings out the best flavors in coffees. Caffeine is somewhat decreased, but there is more caffeine than that of dark roasts per bean.
Medium roasts reach internal temperatures between 210°C (410°F) and 220°C (428°F) — between the end of the first crack and just before the beginning of the second crack.
Dark roasted coffees are dark brown in color, like chocolate, or sometimes almost black. They are usually considered bold, rich and dark. However, in unskilled hands or inexpensive beans can give you a charred, acrid or burnt flavor. This flavor can eclipse the origin flavors in the roasting process. They have a sheen of oil on the surface, which is usually evident in the cup when the dark roast coffee is brewed. The coffee will generally have a bitter and smoky or even burnt taste. The amount of caffeine per bean is decreased compared to the light and medium roasts.
It’s an industry secret that when you have beans you’re trying to use up rather than putting them on sale you put them into a French Roast. Almost anything tastes alike in a French Roast (sorry, coffee roaster friends).
To reach the level of a dark roast, coffee beans are roasted to an internal temperature of 240°C (464°F) — about the end of the second crack — or beyond.
Although caffeine levels differ, the difference is marginal and dependent on to how you measure your coffee. If you measure your coffee by scoops, light roast will have more caffeine. Since the beans are denser than a dark roast. However, if you weigh out your scoops, they will both have similar amounts of caffeine per cup. Most people at home measure them by scoops compared to commercial coffee makers that usually go by weight.
So our conclusion is it really is dependent on preference and taste. If you want a strong kick of caffeine then we suggest a lighter roast but if you want a bold taste then darker roast it is. However, if you are getting a cup of coffee from a coffee shop, barista or a commercial brewing machine that brews according to weight then the difference in caffeine is minor.
For us, Medium roast is our preference and recommendation because it provides a balance of caffeine, keeps the origin flavor and has still has a bit of that boldness. That’s why we serve our 734 coffee as a medium roast.