I was wondering how common it is to compare the weight of the pre-shot espresso pack with the post-shot weight. It seems to me that this might be a good way to check saturation. Once all the excess water drains out of grounds, too light a post-shot pack weight probably would indicate channeling or failure to extract from a percentage of grounds. Today I had a very decent shot on a Magister HX (MS-40) and went from something like 15 grams to 28 grams pre- and post-shot.

Have others measured this much? Is there a thread for this? Sorry if I have posted about something that has a lot of discussion already. I just got interested in this again after doing a very belated brew head gasket change which made my machine behave like it was new again.

Ron

No, it is not a common thing. The only person I know of that has tried to calculate the extraction based on the post extraction weight was Jim. To really tell how much solids were extracted you would need a humidity meter and a very accurate scale. Not the $12 ebay specials. You would have to get the moisture content of the coffee before the shot, then bake the puck in the oven to dry it out to the exact same moisture content. Then you could use your $600 calibrated scale to weigh the pucks to see how much solid material was extracted. Lot of work.

I was wondering how common it is to compare the weight of the pre-shot espresso pack with the post-shot weight.

It is not a common ritual but is discussed here: WBC Procedure for Measurement of Brewing Water Temperature - see section 4.3 . Other than trying to come up with a good number for total water flow, I can't think of a purpose for this measurement.