How repeatable are grinder dosers when used as designed?

I've heard around 1/3 gram; never tested it

Not exactly on point, but not worth its own thread.

I put 6 grams of coffee through my Macap this AM, brushed it out afterwards and weighed the grinds that were left in the grinder. A little over 1 gram remained. I clean the grinder after each session, so in the first grind of a session I am producing only 5 grams of coffee and in subsequent grindings, I am getting 6 grams.

By "as designed" I meant grind enough coffee to fill the doser, catch several single pulls of the doser and weigh each dose.

An interesting side test would be to refill the doser and let it sit for 30 minutes, then repeat the dose weighing test.

I don't have a doser or I would do the test myself. Any Angelenos willing to supply the grinder, I'll supply the coffee and scale.

cafeIKE wrote:How repeatable are grinder dosers when used as designed?

If you remind me after next week when I'm back in town, I'll test it with old beans. From what I've read, they are accurate to less than a gram when used as designed (i.e., filled well above the wedges). Some grinders like the Cimbali Max and Mazzer Kony have auto-dosers, i.e., the motor runs every 12 pulls to keep the doser full. The grinder's main switch can override this behavior.

BTW, is this a question of idle curiosity or is there a deeper meaning?

HB wrote:BTW, is this a question of idle curiosity or is there a deeper meaning?

Much has been written of late of the need for a 0.1g scale.

For the past couple of days, I've been grinding as normal into the PF, then weighing before tamping. Doses of about 14.5g±0.5g are pretty consistent.

In bars where I've had the best and most consistent shots, the barista simply pulls the doser, tamps a bit, locks and pulls. Nary a scale to found. If dosers have a reasonable repeatability of say ±0.5g, then that more or less establishes the bench mark for consistency.

cafeIKE wrote:If dosers have a reasonable repeatability of say ±0.5g, then that more or less establishes the bench mark for consistency.

That's certainly accurate enough for me.

In Exercises for tuning your barista techniques, I advocated within 0.5 grams, though I would not fuss too much if it's within 0.7 grams. Sometimes I'll intentionally shift the dose to change the pour time; my rough rule of thumb for most blends is that one gram adds/subtracts about four seconds of pour time.

cafeIKE wrote: In bars where I've had the best and most consistent shots, the barista simply pulls the doser, tamps a bit, locks and pulls. Nary a scale to found.

No leveling or distribution involved? Most pros will dose by volume, using a version of Stockfleth's, the Chicago Chop, etc. Once you get the 'fill 'er up' method down, the doses will be fairly similar.

0.5 gram my be fine for day to day use but when you are trying to compare shots between grinders, or machines, you need to be as accurate as possible. I have a 0.1g scale and only use it when I am doing bench testing or blending.

Psyd wrote:No leveling or distribution involved? Most pros will dose by volume, using a version of Stockfleth's, the Chicago Chop, etc. Once you get the 'fill 'er up' method down, the doses will be fairly similar.

Asking for a 'Chicago Chop' in Italy will probably get you directions to the steakhouse in the nearest chain American hotel.