Spraying Coffee Before Grinding

Some coffee grinders come with a small spray bottle included in the package. But why do manufacturers recommend spraying coffee beans with water before grinding? Let’s dive into the purpose of this practice and whether it’s necessary.

When you place beans in a coffee grinder for a single serving, they don’t fully fill the grinding chamber. As a result, the beans move around more during the grinding process, generating static. This static causes the coffee grounds to stick to the sides of the grinder or scatter everywhere, which can prevent a full and efficient grind. Spraying the beans with water beforehand can help minimize this issue.

It is believed that the idea of moistening coffee beans before grinding was first proposed by David Ross in 2005 in the Usenet community alt.coffee. Since then, this method has been known as the Ross Droplet Technique (RDT).

The simplest way to apply the RDT is to wet a small object like a spoon handle, chopstick, or even your finger under the tap. Then, stir the beans with the dampened object before putting them into the grinder.

A spray bottle offers a more convenient way to evenly distribute the water among the beans, ensuring that all beans are slightly moistened.

Should I spray water on the beans if I’m using a manual coffee grinder?

Even though static is more of an issue with electric grinders, you might still run into it with a manual one—whether it’s a Hario, 1Zpresso, Comandante, or whatever:

In our experiment, the RDT definitely helps reduce static. On the left, you can see the grind result without spraying water, and on the right – with the spray:

The difference between grinding wet and dry coffee beans

Pre-moistened coffee beans produce fewer airborne particles and grind more evenly. The coffee grounds are less likely to clump together, and they don’t stick to the walls of the grinder’s chamber, ensuring that all the beans are fully processed.

While this method seems to improve the grinding experience, there are a few nuances to consider:

• If you’re in a humid environment, using a spray bottle may be unnecessary. Too much moisture can make the beans overly wet, which could negatively affect the grind quality.
• The technique may not work well with all grinders. If your grinder has shallow walls near the burrs or blades, the beans may stick to these surfaces, preventing them from being ground properly.
• If you use your grinder multiple times throughout the day, excess moisture could accumulate inside the grinder. This buildup can lead to mechanical issues or even damage the grinder over time.

Final thoughts

Spraying coffee beans with water before grinding, or using the Ross Droplet Technique, can significantly improve the quality of your coffee grind. While it’s not a necessity for every coffee setup, it’s worth considering, especially if you face issues with static or uneven grinds.

However, be mindful of your grinder’s design and your brewing environment. If used properly, this method can enhance your coffee experience and help maintain the longevity of your grinder. For those serious about their coffee, this small step can lead to a noticeable improvement in the final cup.