Swelling properties of roasted coffee particles

Area of Science:

• Food Science
• Material Science

Background:

• Investigates the swelling behavior of roasted coffee particles in water.
• Examines the impact of swelling on particle diameter.

Purpose of the Study:

• To understand the influence of initial particle size, roasting degree, and temperature on coffee particle swelling.
• To evaluate the time dependency of swelling and particle shape.

Main Methods:

• Laser-diffraction analysis
• Microscopy

Main Results:

• Particle erosion occurs, increasing fine particle fraction, especially at higher temperatures.
• Total relative particle size increase is approximately 15%, independent of initial size or roast degree.
• Swelling is rapid, reaching 60-80% in 30 seconds and completing within 4 minutes.

Conclusions:

• Provides a better understanding of wetting's impact on coffee brewing.
• Clarifies previous swelling results by accounting for erosion and degassing.
• Offers a robust method for quantifying coffee particle swelling for process optimization.