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
So espresso is very picky about measurements. 18g of beans into your grinder ideally yields 18g out. Not getting that amount of ground coffee out of the grinder and hence into your portafilter will heavily influence the taste.
Is there an acceptable margin of error? It’s wild to me that static would cause a difference outside of that margin.
Why not measure your grinds versus measuring your beans? Or, if you know how much you lose to static, could you compensate for that in your bean weigh?
These solutions seem easier than RDT.
That’s the trouble, it didn’t get vaporized or vanish. It’s still in the grinder, or sticking to the collection bin. I’m not an expert or anything but I suspect that the residue oxidizing and mixing with the next batch will have more flavor impact than being a little off with your measurement.
Honestly, is incredibly easy to spritz them when measuring, throw em in the grinder and be done.
I’ve never really read much on the actual effects of water on the coffee flavor itself, just the wonderful lack of static. I don’t screw with espresso as I’m at my limit for expensive hobbies. I have in the past and a half gram will make a noticable difference in a shot. Enough to ruin it? Completely subjective.
So the goal is to make your “ideal” shot for the beans you have. Reproducibly. So right off the bat if the ground weight out isn’t equal to the unground weight in (as close and reproducible as possible) then you’ll have to adjust other factors for each shot. Which can quickly become extremely complicated. Especially with static where the amount of loss is going to vary every time.
I get 18g out when I put 18 in, 17 on a very bad day maybe. I think with most good grinders the loss is maximum of 1g and typically substantially less.