SJM wrote: dose weight - dry weight = x
x/dose weight = extraction %

It seems to work when I do my old rusty algebra on it.

That's right.

About your previous point on the weight of coffee and weight of water. The coffee particles can be thought of as a sponge of insoluble cellulose, impregnated with soluble and suspendable coffee solids. Once the extraction is done, the cellulose sponge is intact, most of the solubles and suspendables are in the cup, and the sponge is soaked with water. So using the net (after) weight to estimate the water holding capacity would actually be better. However, I think the reports in the coffee literature use the gross (before) weight.

another_jim wrote: That's right. So using the net (after) weight to estimate the water holding capacity would actually be better. However, I think the reports in the coffee literature use the gross (before) weight.

I will try to wrap my mind around that discrepancy when using the numbers.

There's a relevant Iris Dement song: "Easy's Getting Harder All the Time".

Susan

Would this
http://www.amazon.com/Temperature-Compe ... 008562GD0/

be a reasonable toy for comparing the data I'm getting from drying pucks to....?

It's in my range of affordability....))

Susan

It's one decimal place short, and the units will be wrong. But ...

If you make a scatter graph the brix readings of the espresso on the Y axis with the gross extraction value you get from the corresponding puck on the X axis; you can see how well they correlate (i.e fall on a smooth line, rather than being scattered).

PS. You should also weigh the shot. The graph will be better if you multiply the brix reading with the shot weight (i.e. solids concentration per unit weight * total weight = total solids). The brix reading isn't solids concentration, but is a rough correlate of it. So by multiplying it with shot weight, you will turn it into a number that should roughly correlate with the extracted solids in the puck. Hope this makes sense; explaining math verbally is always a mess.

I understood it and immediately realized drying and weighing pucks is as far as I'm probably gonna take this particular set of information gatherings. I'm gonna pass on the brix gizmo.

Susan

I hope you take notes on the taste of the shots; for me, it's always interesting to hear how the prep changes impact taste

I'm not a very good researcher, and I'm a very slow learner, but ....
What happened from my testing was what I have been told should have happened even without it, which is that I tightened the grind, lowered the dose, and improved the taste in the cup.

What else is there?

Then yesterday the SAMA went back online after a month or two out while I replaced her heater. Of course I had to dry her first puck too, and the % of my extraction looks to be about 17%. I was my usual not-terribly rigorous self, but.....in spite of the drubbing the process gets, I find it eye-opening and even fun.

Of course I'm also the person who thinks 6 yards of compost is a great gift...)))

SJM wrote: I tightened the grind, lowered the dose, and improved the taste in the cup.

Did the extraction numbers go up? Just wondering

... yesterday the SAMA went back online after a month or two out while I replaced her heater. Of course I had to dry her first puck too, and the % of my extraction looks to be about 17% ...

Glad the SAMA is back. Maybe tighten up the grind as well?

The numbers did not go up, but I suspect that that is because my methodology is so imprecise. I'll bet if I had been more meticulous that there would have been a change as indicated by the taste improvement. (Or if I had a refractometer....)

I'm going to have to play with the SAMA a bit now that she's back online.

Before this I was using my Pharos to grind for it, and I haven't yet figured out quite how to set the K-10. With the Pharos I was using a 16 gram dose in the SAMA. The K-10 has changed everything; I can only fit 15 grams into the basket using the same grind I was pulling a day or so ago for the Classic. And...This morning's pull looked like I was trying for the record for the least output in the longest time....

And....I can't help but wonder about the difference in pulling through the SAMA's narrow and deep basket compared to the Classic's wide and shallow one. Something tells me we are appling and oranging here...but I'd like to be able to use the Compak for both machines.

If you have the time and patience I recommend air drying at room temperature, since the coffee was not oven-dry before extraction. A small point perhaps, but worth considering.

I did a series of these a while back with the Caravel, and got very consistent results. 16g dose, 13g air dry spent puck, 3g "dissolved" solids, or ~20%. If any were undissolved they went down the hatch with the shot anyway, so I received all 3g of coffee. I even estimated the mg caffeine for this dose from an Illy can, but don't remember what it was.

Never tried it with the Sama, but I assume it would be similar.