A Little Water Goes a Long Way

In the simplest of terms, static electricity is generated when two surfaces come into contact and then separate, leaving an imbalance of electrical charges. A familiar example is rubbing a balloon against your hair and watching it mysteriously cling to just about anything. It’s a phenomenon we’ve all experienced, although perhaps not everyone has found it quite so entertaining.

Coffee grinders are no exception.

As beans pass through the burrs and are broken into smaller particles, electrical charges develop. Depending on the conditions, these charges can cause grounds to cling to the burrs, accumulate inside the grinder, or scatter across your countertop.

All grinders experience static to some degree. The HG-1 Prime is no different.

Why Some Days Are Worse Than Others

One of the biggest influences on static is humidity.

In dry environments, particularly during winter, static tends to be more pronounced. During warmer, more humid months, the problem often diminishes. Anyone who has experienced a dry Midwestern winter will be familiar with the phenomenon, whether from their coffee grinder or the occasional unexpected shock from a doorknob.

The coffee itself also plays a role. Different beans, roast levels, and grinding conditions can produce noticeably different amounts of static.

This explains why the same grinder can behave perfectly one morning and leave you wondering what happened the next.

Fortunately, there’s a remarkably simple solution.

The Ross Droplet Technique

During the original HG-1’s development, one of our early customers, Tom C., suggested an approach he remembered encountering elsewhere.

Rather than trying to increase the humidity around the grinder, why not introduce a tiny amount of moisture directly to the coffee beans?

Tom tested the idea with the HG-1, found it remarkably effective, and introduced us to what he called the Ross Droplet Technique, or RDT.

The principle couldn’t be simpler.

Add a tiny amount of water to your beans before grinding, and static can be dramatically reduced.

At the time, this seemed like another one of those peculiar rituals associated with manual coffee preparation. Much like stirring grounds before tamping, it was an additional step that might have appeared unnecessary to someone unfamiliar with the problem.

Today, RDT is widely practiced among coffee enthusiasts. Small spray bottles designed specifically for dosing coffee beans are readily available, and the technique has become a familiar part of many single-dose grinding routines.

What was once a rather unconventional suggestion has become an established way of dealing with grinder static.

The Science Has Caught Up

In 2023, researchers published a study examining the relationship between moisture, electrical charge, and coffee grinding.

Their findings helped explain why RDT works. Adding a small amount of water before grinding can substantially reduce the electrical charge generated as beans are fractured, limiting the tendency of ground coffee to cling to surfaces or scatter.

The research also explored how moisture and static influence the behavior of ground coffee during espresso preparation.

It’s an interesting example of a practical technique developed and shared within the coffee community eventually attracting scientific investigation.

Sometimes experimentation comes first, and the explanation follows.

How to Use RDT with the HG-1 Prime

The process is straightforward.

1. Weigh your beans. Measure your usual dose before grinding.
2. Add a little water. A single light mist from a small spray bottle is a good starting point.
3. Distribute the moisture. Give the beans a quick shake or stir so the moisture is spread across their surfaces.
4. Grind as usual. Observe whether static and grounds retention have improved.

The objective is to introduce just enough moisture to reduce static, not to make the beans noticeably wet.

Start with the smallest practical amount and adjust only if necessary. Excessive moisture is unnecessary and may encourage residue buildup inside the grinder.

Depending on your beans and local humidity, you may find that RDT makes a noticeable difference. On other days, you might not need it at all.

A Matter of Preference

Over the years, we’ve heard of just about every imaginable method for adding water to coffee beans.

Some people flick a drop or two from their fingertips. Others use eyedroppers, pipettes, or a damp spoon. My personal favorite remains the little vermouth atomizers originally intended for making martinis. Filled with water, of course.

These days, a small spray bottle is probably the simplest and most convenient solution.

But there’s no need to turn RDT into another elaborate ritual.

The HG-1 Prime was designed with a short, direct grind path to minimize retention. RDT is simply another tool available when environmental conditions or particular coffees make static more troublesome.

If your grounds are flowing cleanly and retention is minimal, there’s no reason to introduce water unnecessarily.

And if you’re grinding in the middle of a dry winter and discovering more coffee on your countertop than you’d like, a little moisture might be all you need.

Sometimes the simplest solutions are the ones that stick.