What key measurement does a refractometer provide in coffee brewing?

A refractometer is an instrument specifically used to measure the Total Dissolved Solids (TDS) in a solution, which in the context of coffee brewing translates to determining the concentration of soluble compounds extracted during the brewing process. TDS is expressed in parts per million (ppm) or as a percentage, and it gives baristas valuable insight into the strength of the brewed coffee.

Monitoring TDS allows for adjustments in brewing parameters to optimize flavor extraction, as it directly correlates to how much of the coffee's soluble ingredients have been successfully dissolved into the water. This can be crucial for achieving balance and consistency in coffee brewing.

While yield, temperature, and pressure are all important aspects of brewing coffee, they do not provide the comprehensive insight that TDS measurement offers when it comes to understanding extraction efficiency and balance of flavors in the final cup.