Reducing Static in your Grinder

For all the fun there is to be had with coffee, there’s one thing that’s sure to ruin your mood: static. It causes your grounds to fly everywhere, sticking to your hands and making a mess of your counter before you’ve even started brewing. Different grinders, coffees, and environments may produce more or less static but can anything be done if your favorite coffee doesn’t agree with your grinder? Watch our brief video below to find out!

Luckily, the answer is yes. The home barista community refers to it as the “Ross Droplet Technique” -- or simply RDT. It’s named after David Ross who seems to have pioneered the idea back in 2005. It would be years before this idea took hold amongst the growing home barista community, starting in the home-barista.com forums where a poster by the name of Chris resurfaced the concept leading to a thread full of people comparing their pre-RDT static issues to their results when they employed the technique.

So how do you do it? Simply add a couple of droplets of water to your beans before grinding them. If you’re worried about the idea of putting water in your grinder, you’ve got good instincts. In truth, grinders are dealing with some amount of water all the time whether it’s from the moisture content of the beans or from humid air. Think of those few drops of water as a way to simulate higher humidity for your grinder. Tests by industry veterans and novices alike have shown that you can use the Ross Droplet Technique for years without damage or rust on your burrs.

There are a few ways to go about doing this. You’ll want the droplets to be fairly evenly distributed among the beans. We’ve found the simplest way of doing this is to take a stick, spoon handle, or even just your finger and run it under the tap or dip it in a cup of water. Then just use it to stir your dose of beans in a bowl momentarily before popping them into your grinder. You’ll find some sources recommending a spray bottle. This can be a handy way to keep water on hand, but you’ll still want to stir the beans afterward.

The reason why this works is also pretty simple. The reason that static electricity causes your coffee grounds to fly everywhere is that there’s an imbalance between the charge of the particles of coffee and the grinder. These charges cause the particles and grinder to behave like two magnets with their north poles facing each other: they repel. The more water there is in the air the more conductive it is – this is why you may have noticed that you’ll get more static during the drier months. By adding a bit of water we make the environment within the grinder more conductive which allows the static charges to flow and dissipate, thereby preventing those grounds from flying across your counter.

Let’s talk precautions. You’ll really want to keep the water you use to a minimum. While grinders can handle a little bit of moisture without damage or rust, they’re not big fans of the stuff. Play it safe and use as little water as you can to produce the most beneficial effects.

Further, the Ross Droplet Technique should really only be used when single dosing and the water should always be added immediately before grinding. Leaving beans in contact with water for any period of time will result in the flavorful compounds inside breaking down, meaning they won’t taste quite as good when you go to brew with them. But that doesn’t mean this is only for espresso! If you single dose with a brew grinder like the Baratza Virtuoso+ or the Fellow Ode grinder you can use RDT to reduce static.