Spoiler, its RDT
In case people do nto know what RDT is, which they really should if they have been into coffee for a little while as it makes a big difference:
RDT is Ross Droplet Technique, which is very much adding water to beans. Named after David Ross who came up with it back in 2005
My favorite part of that paper is that thanks to them actually measuring particulate size we now have empirical proof adding a small amount of water improves the consistency of your grind:
it is clear that the inclusion of even small quantities of water (as low as 5μLg−1) results in an immediate reduction in electrostatic aggregates of boulders and fines
How does wet beans not gum up the mill?
If you make them that wet you are doing it wrong, lol.
You only need a drop or two of water for espresso and only slightly more for a larger amount of beans for a pour over, it’s a tiny amount. People have been doing this since 2005 without problems.
Check out: https://www.youtube.com/watch?v=GuqVUsMPs-U&t=2620s
If you don’t believe me
Ok, thanks. I’ve got a decent mill with a hopper. Would something as simple as suspending a damp sponge in the hopper be sufficient to raise the moisture content to reduce static charge or does it have to be physically applied to the beans to be effective?
I wouldn’t recommend that approach, its more suited to single dosing, which is based around grinding only the amount of beans you need for that single lot of coffee by only feeding the hopper with the amount of beans needed rather than using the hopper for bean storage.
So weighing out your beans first for a single espresso or pot of pour over, wetting those beans with a drop or two at most of water, giving them a shake/stir, then feeding them into the hopper and making sure everything comes out that you put in.
Single dosing makes it easier to get the exact amount of coffee by weight each time from cheaper grinders and can lower retention (how much ground coffee the grinder holds in its burr chamber and spout) when combined with RDT and flushing out the grinder with something like bellows and discarding what comes out as its mostly chaff and fines that you do not want. Coffee tends to build up even in expensive grinders without flushing it out, this goes stale over even a few hours and works its way into your normal cups of coffee.
Grinding by weight is still pretty limited availability, most with a hopper tend to offer grinding by time, which is nowhere near as accurate. Grinding by weight makes it easier to make your coffee more predictable, its especially important for espresso as you are trying to fill the basket almost but not quite the top. Espresso is better measured by volume as coffee density varies by roast type and by time since the beans were roasted, but that is much harder to do than by weight on a regular basis so most people just use weight.
You add a very very small amount of water. Like one spray from a tiny spray bottle.
Dear scientists, get the fuck back to working on saving the planet from boiling us alive k thx.
OK, I’m loading a spray bottle for tomorrow’s shot.
Even slightly wetting the end of your finger and stirring it through the beans can be enough to make a difference.
I use water for my filter grind. I have a measure cup for the beans. Then I use a wet teaspoon and stir it around in the measure cup. If I grind 10 grams the teaspoon is almost dry. If I grind 30-40 grams I have a solid water drop on the spoon. But it varies with the beans. Some beans produce more static and some less. If one or two beans get most of the water they will stick in the grinder. It’s also easier to keep the grinder clean when there is less small static particles flying everywhere.
Not sure if you have watched Lance’s video I linked elsewhere in the post but they measured particle size, RDT improved uniformity of particle size. This to me is the first empirical evidence of the actual benefit of RDT over and above less mess with grinding. For what can be a completely free and quick upgrade that seems always worth doing.
While WDT does need a tool and even a homemade one isn’t completely free it’s ability to better distribute grinds in the basket I would also say it’s an essential upgrade as it can be so low cost
Anything else like slow feeding, hot starting that are free upgrades no matter how small for cheap to midrange grinders that lack prefeeding augurs or other chokes that prevent overloading the burrs seem no brainers to me.
