Coffee is the lifeline for many people, providing the necessary caffeine boost to start the day. It can be enjoyed in different forms, hot or cold, and served with various accompaniments.

However, what many people may not realize is that coffee owes its thick texture to a sneaky molecular trick.

Background

Despite being a popular beverage, there is still a lot that scientists don’t know about coffee. The complex chemistry and intricate molecular interactions that make up coffee’s flavor and texture are still being studied.

The thick texture, or what is commonly known as mouthfeel, is one of the most prominent features of coffee that sets it apart from other beverages.

Scientists have found that coffee is a complex solution containing numerous molecules, including carbohydrates, proteins, and lipids, which all play vital roles in shaping its taste and texture.

To achieve its thick texture, coffee relies on a process called “colloidal aggregation,” which is achieved through several molecular mechanisms.

Colloidal Aggregation

Colloidal aggregation is a process that occurs when particles in a solution clump together. This clumping behavior changes the texture of the solution, causing it to be thicker, denser, and more opaque.

Previous studies have shown that colloidal aggregation plays a significant role in the texture of beverages such as milk, beer, and wine. But, until recently, coffee’s thick texture was still a mystery.

Scientists from Northwestern University, USA, have found that the sneaky trick behind coffee’s thick texture is colloidal aggregation.

They found that the various molecules present in coffee interact with each other in a specific way that leads to colloid formation.

Protein Molecules and Lipids

The scientists found that two critical components in coffee contribute to its colloidal aggregation.

The protein molecules present in coffee, such as melanoidins and glycoproteins, act as aggregating particles that interact with each other, forming small clumps. At the same time, lipids, such as fatty acids and oils, help to stabilize these clumps, preventing them from falling apart.

However, protein molecules and lipids alone cannot explain coffee’s entire texture. The scientists found that carbohydrates also play a significant role.

The carbohydrates present in coffee act as a barrier or protective layer around the clumps, helping to protect them from breakdown.

The Role of Roasting and Brewing

Roasting is a critical step in coffee production, and it can significantly impact the texture of the final product.

During roasting, coffee beans undergo a series of chemical reactions that break down carbohydrates and proteins, leading to the formation of melanoidins. The researchers found that melanoidins contribute significantly to coffee’s colloidal aggregation and, thus, its thick texture.

Brewing is another crucial step in coffee preparation. The brewing process can significantly impact the extraction of various molecules, including carbohydrates, proteins, and lipids, which all play critical roles in coffee’s texture.

Over or under-extraction of these molecules can lead to a change in texture, affecting the overall taste experience.

Conclusion

Coffee’s thick texture is a unique feature that sets it apart from other beverages. Its complex chemistry, interactions between various molecules, and the roasting and brewing processes all contribute to its texture.

Scientists are still studying coffee’s complex molecular interactions and hope to discover more exciting aspects of this beloved beverage in the future.