How A TDS Score Applies To Coffee


At Ampersand Coffee Roasters, we are constantly experimenting with coffee. Coffee remains one of the most complex drinks that we consume with up to 400 different compounds that contribute to the flavor of the coffee. Our job is to see how we can get the best flavor out of our coffees by manipulating these components in different ways. The scientific process is something that we use every single day and we document everything that we do. One crucial piece of equipment is extremely important in our testing process: our refractometer (also known as TDS meter)


What is a Refractometer?

It sounds pretty crazy but it is simply a piece of equipment that can measure the level at which light direction changes (or gets refracted) because of solids that are creating that change. Refractometer are very commonly used in many different industries. However, they have more recently been used within the craft beer and specialty coffee world.


How It Applies To Ampersand

The process of making coffee involves pouring water over roasted coffee that is ground, and allowing that water to extract caffeine and flavors from the coffee grounds. Just like the ABV level in alcohol, we can measure the strength of our coffee using our TDS meter. The TDS score will tell us how much of the coffee dissolved solids made it into the cup. We test every single coffee that we make to ensure that we are not only consistent, but to learn more about what the coffee is doing throughout the extraction process. A TDS score is generally using a parts per million number and then applying a conversion factor to make it a more reasonable number. For our application, the higher the score on the TDS, the stronger the coffee. We are always shooting for a score above 2.1 to ensure that the coffee does not taste watery and offers a balanced body with a complexity of flavor and acidity. Each coffee is different and will taste best at different TDS scores. So we dial every single coffee individually to maximize the end result.


When you stop by our tasting lab, we are most likely conducting an experiment of some sort to learn more about coffee. While it is becoming a bit more common, we are still one of the few coffee roasters that use a TDS meter on a regular basis. This also includes big coffee roasters that are roastings millions of pounds per year. The process from how it is grown to how it lands in a cup is fascinating. There are so many different factors that can contribute to an incredible flavor and t is our job to figure out that mystery with every coffee. While we perform many experiments, our TDS meter is with us every step of the way, continually giving us more information about what is going on inside of the coffee. While this isn’t the only tool, it is essential to our experiments in creating a better tasting coffee for everybody to enjoy.