The coffee that we drink comes from ripe cherries, the fruit of the coffee plant. However, we do not drink the squeezed fruit. Rather, we get coffee from the beans of the coffee plant and not the ripe beans but rather processed and then roasted coffee beans. Removing the coffee fruit or cherry makes sense as we do not use it to make coffee but why do we roast coffee as well? If you have ever had brewed green coffee you will remember the grassy, acidic and earthy taste somewhat a mix of herbal and green tea. This taste is nothing like what we are familiar with as coffee drinkers.
What Does Brewing Do to Coffee?
By roasting coffee we remove the “grassy” taste, reduce its moisture content and create complex chemicals with complex flavors and aroma. With darker roasts we caramelize the coffee bean creating a sweet taste. Over the years coffee roasting has always been done to create the desired taste and aroma of the coffee that we love. Simultaneously we create antioxidants that provide many health benefits for coffee drinkers. Specifically, heating coffee beans degrades chlorogenic acids making the coffee less sour and creating sweetness. Roasting turns coffee beans from green or greenish tan to brown. During the roasting process oils trapped in the bean migrate to the surface creating a glossy or shiny appearance. Roasting does not change the amount of caffeine in coffee beans. Depending on temperature and time of roasting we get a light brown bean with fruity and acidic flavors. Increased temperature and time reduce acidity and lead to a chocolatey, smoky or bitter taste.
Coffee Roasting and Shelf Life
Ideally we roast coffee just before we grind up the beans and brew a pot. For shelf life it is better to keep green coffee beans which, when properly stored, keep their freshness up to three years. Roasted coffee beans, when properly stored, can retain their freshness for up to three months. When roasted coffee is ground it begins to lose freshness immediately. Roasting has to do with getting the aroma and flavor that you want and not with keeping your coffee fresh.
Who First Roasted Coffee?
When coffee first reached Yemen in the Middle East in the 13th century was when we have the first historical evidence of coffee roasting. As coffee spread across the Ottoman Empire to Constantinople and into Europe it was roasted coffee that became popular and spread across the globe.
What Is the Best Coffee Roast?
There are four basic levels of coffee roasting. They are a light roast, a medium roast, a medium dark roast, and a dark roast. Each darker level of roast is created with a slightly higher temperature and slightly longer roasting time. A light roast retains much of the original flavor of the coffee bean. From medium to a dark roast coffee has a steadily more caramelized and smokier flavor and increasingly more oil. The best coffee roast is the one that you like best. To the extent that you want to preserve all of the unique flavors of your coffee beans a light roast is better but if you prefer the stronger, caramelized flavor of a darker roast that is the one for you.