Welcome to this exciting article, where we will explore the fascinating physical changes that coffee beans undergo during the roasting process. Get ready to enter the world of coffee transformation, from a green seed to a delicious aromatic jewel that we love so much. We'll dive into the physical changes that take place inside the toaster. Get ready to get excited and learn more about your favorite drink!
The Importance of the Physical Structure of Coffee
The anatomy of a coffee bean is essential in creating the flavor and aroma of the final roasted product. Without the proper physical structure, the necessary chemical reactions could not take place. Imagine the internal structure of the beans as the foundation on which the sensory experience of coffee is built.
The Dramatic Physical Changes that Coffee Experiences
When coffee beans enter the roaster, they undergo physical changes both on the outside and inside. It's time to explore the exciting changes that occur during roasting!
The Color of the Coffee Bean
One of the most notable physical changes in coffee is its change in color. The blue-green grains transform into shades of brown due to the production of melanoidins, which are formed when sugars and amino acids react under heat. Additionally, the outer layer, known as "silver skin" or straw, comes off during roasting.
Coffee Moisture and Mass
The moisture content in coffee beans is reduced during roasting, going from 10-12% to around 2.5%. Additionally, chemical reactions generate additional water that vaporizes during the process. This causes a decrease in the total mass of the grains, with a weight loss ranging between 12% and 20%.
Volume and Porosity of coffee beans
Coffee beans have strong cell walls that become rubbery during roasting due to the presence of polysaccharides. As water transforms into gas and pressure builds up inside the grains, they experience an increase in volume and a decrease in density. Porosity also increases, which influences solubility and the ability to obtain a delicious drink.
Oils from a coffee bean
During roasting, the lipids or oils present in the beans migrate to the surface. These compounds are vital to retain the volatile flavors and aromas inside the grain. The distribution of oils on the surface directly affects the flavor of the coffee.
You have discovered the exciting physical changes that coffee beans undergo during roasting! From color change to moisture loss, volume increase and oil migration, each stage contributes to creating the beverage we love so much. In the second part of this series, we will explore the chemical changes that accompany these physical processes. Do not miss it!