As coffee plants grow, they undergo many complex chemical changes that shape the quality and flavor of the beans. These processes are all influenced by the plant’s environment, its developmental stage, and its access to nutrients, as we discussed on the last page.
Key biochemical pathways, such as photosynthesis and lipid synthesis drive the production of compounds that define, the aroma, flavor, and texture of the coffee. This is what professional coffee tasters look for when they test coffee, using a method called cupping. The growth stage also affects the formation of sugars, and acids in the coffee cherries – laying the groundwork for a rich cup of joe!
Photosynthesis in Coffee Plants
Photosynthesis is a fundamental process for coffee plant growth and development. However, compared to other plants coffee trees display relatively low photosynthesis rates. To combat this lower level of photosynthesis, farmers change the conditions of their crops to yield different results. A common example of this is growing coffee plants at a higher altitude, due to the colder temperatures slowing the growth of the plant and allowing more chemical development to occur.
Lipid Synthesis in Coffee
The lipid fraction, a group of lipids that can be separated, of coffee beans undergo significant changes during plant growth as well.
During the fruit development of the coffee bean, the lipid composition of a coffee bean changes. Sucrose levels increase in Arabica cultivars whereas Rubusta cultivars accumulate higher levels of fructose and glucose. These changes directly change the flavor of your coffee, as higher levels of fructose and glucose lead to fruitier or berry-like flavors.
Caffeine Synthesis in Coffee
Caffeine biosynthesis follows a pattern during the development of most coffee fruits. The highest caffeine content in the seeds is reached between eight and twelve weeks after flowering, gradually decreasing after sixteen weeks. However, the processing of the coffee can also change the caffeine content, which is how we get different roasts. That will be discussed later.
