Fun with 0.1 Gram Scales Part I: dosing whole beans

[another_jim]

Ever wonder how accurate your volumetric dosing is? I did, so bought a 0.1 gram resolution scale. Why not 0.01? A full city roasted coffee bean weighs roughly 0.2 grams, and I'm not cutting beans to dose!

Here's what happens if you try to dose coffee beans with a typical coffee measuring spoon or a filter basket:

-- Finger swipe across the top to level: standard deviation 0.45 grams (8.3 grams average on the spoon I used)
-- Heap it as far as it'll go: standard deviation 0.30 grams (11.0 grams average on the same spoon)
-- Mash it down so it's flat: standard deviation 0.15 grams (8.8 grams average, still the same spoon)

The mash method basically gets it virtually to the nearest bean, and is therefore about as accurate as weighing.

I'm not sure if the spoon makes any difference. In this case, it's my sole surviving bit of pre-internet coffee gear, a Starbuck's (7gram - maybe for Starbucks level roasts!) coffee measure, roughly cubical in shape.

[WR]

Thanks Jim... I've been meaning to pick up a tenth gram scale to figure out what my 7 gram scoop really dosed. That's really interesting info as I've been heaping my beans which may be creating some consistency issues by occasionally forcing a huge unintentional overdose. I'll try the "schulman flat pack" in the morning! Of course maybe we should all just abandon this silly volumetric stuff and just count beans one by one into the hopper... -Will

[another_jim]

I'm not sure how much ultra-accurate dosing helps in achieving consistent results:

-- If one uses a bottomless PF, one can compnesate for most dose, grind and tamping variations by cutting the shot at the right point (good levelling is another story, that is a must). However, it's unclear to me how much the taste varies in properly stopped shots of various doses or grind levels.

-- If one is using a full-auto machine that doses the shot volume, then I suppose being ultraconsistent in dosing and grind is mandatory.

I'm slowly assembling the bits and pieces needed to do more decisive espresso testing; this is just one of the items.

[randomperson]

Even after grinding, the so-called 7 gram scoops show some variability. I measured 8 grams per scoop of ground coffee, levelled. Of course, this depends on the grind setting and of course the coffee. But in any case I now religiously use a .1 gram scale just to turn one variable (dose) into a constant 17.5 grams, 17 after levelling a knocking off the odd small pile of grinds. I found this led to better consistency than the eyeball/volume dosing method and takes one more variable out of the equation!