Grinders: Efficiency

[Gouezeri]

Following all sorts of threads on grinders, one thing that doesn't seem to be discussed much is the waste grounds that don't make it into our PFs. With doser, or doserless, is surely not as important as the percentage of beans put into the hopper and the percentage of fresh grinds we get out.
Both SimonP and I have modifed our dosers to make sure that there's no waste left behind, but what about the chutes between? Having recently acquired a Rocky, I was surprised at the amount of grounds I had to dig out of the chute.
So I've been looking at grinders in London since and without being able to test or measure them all, I've been surprised by how far the coffee grounds actually have to travel from burrs to doser/PF; in fact the Rocky seems to compare very well with grinders such as the Isomac/Aerolatte, Innova I-2 and La Pavoni Jolly. By my measurements, there's roughly 3.5cm between the chamber where the burrs are and the end of the chute.
Consequently I thought I'd measure how much was left behind, if I didn't "dig it out." Unfortunately, I wasn't all that surprised to learn that a good gram of coffee was left behind, ie. putting 14g of beans in, resulted in ~13g of grounds (without intervention) in the doser. Thankfully, it's easy to recover most of these lost grounds on the Rocky, but it's far from ideal. Surprisingly, this was never a problem with my Solis (though I don't intend to go back to it!).
I'm sure this isn't as much of a problem in a commercial situation, but at home where at least a couple of hours may go by between "cups," I want my ground coffee to be as fresh as possible. So, how much coffee does your grinder lose?

Dom

Ps. this was using some of Steve's "Brazil Espresso Perfeito" which is not particularly oily and was ground fine enough for the standard 25s/1oz pour on a Silvia. I think a coarser grind would result in less loss. Nb. I'm not advocating for everybody to buy some from Steve to try this out! At least not unless Steve is willing to provide me with a hottop in return!

[stevenzaat]

Dom,

I own an Innova and have a lot of coffee stick in the chute. I push it with a tea spoon out of the chute, but I still will loose then 5 grams for a 14 gram shot. If I wouldn't push it out of the chute i would probable loose more than 50%!

Before I grind I take all the "left over" out of the chute, to be sure that there will be no stale coffee in my espresso. So probable the Innova will not do better than the Rocky, for the rest I love my grinder.

[Gouezeri]

Steven
It's interesting that you say that, this was a concern that I had had and already expressed in the Members area to Davidd. I almost bought an Innova myself (until I got a good deal on a Rocky) and this was one of the concerns I had. I wonder if the doser model is any different?
At the very least, I'm beginning to think that a doser is useful for "catching" all these grounds as you try and brush them out. Furthermore, that the further the coffee travels from the centre of the burrs, the greater the chance for "waste" coffee to be left behind.
Now what I'm waiting for is a Mazzer owner to speak up and tell all of us wannabes what we're missing out on...
As a side issue, I've now found a valid reason for going to Starbucks... their little "wooden spoons" are just right for clearing out the chute on my Rocky. Bit like borrowing the pencils from Ikea

Dom