another_jim wrote: Do Italian or other filled doser baristas tweak the doser adjustment knob, rather than the grind adjustment, to compensate for flow changes?

Probably not as Mazzers have their dosing adjustments in the middle of the doser. If it's filled with grounds, you can't tweak it.

Faema and Cimbali have the adjustment nut below the doser though.

Besides, I doubt moisture absorption would be a real factor. However, this is just a hunch. You could throw a preweight cup of grounds in the freezer, take them out, have them condensate and absorb any condensation and weigh it afterwards. But since that involves drops of moisture actually on top of the grounds I doubt it's a valid test.

another_jim wrote: ....The normal technique to compensate for staling is to grind finer with the same volume. Thus you use less coffee...

I don't think I am reading this correctly. If someone is dosing by the same volume(I don't...I use a weight scale) and they grind finer, doesn't that mean there is more coffee filling the volume? Thus more coffee being used?

Thank you,
-Darin

I would agree YET depends on the grinder. I was getting very consistent reults with my Fiorenzato T-80 yet would have to alternate between two notches when grinding for one double shot. So I bought a Nuova Simonelli MDX (because of the stepless adjustment) and for 3 months have been unable to get consistent shots day after day.
If I grind 100 grams at one time which is the used over the following two days I get consistent results ... very consistent. This shows it is not the technique I would think. As a note the ground coffee is weighed (14.7 g dalla Corte mini) and my goal is 40g coffee in the cup.
Any experiences with the Nuova Simonelli MDX are welcome.
I noticed in one of Jim's comments that there are less consistent results when the hopper is near to empty. Why would that be?

If you're grinding 100 gm at a time and using it over two days, it's consistently stale, which would go a long way to explaining consistent results. Once you grind the coffee, you've got a 10-15 minute window to pull the shot (and most would say pull it within a minute of grinding for optimal quality in the cup) before oxidation has killed a lot of the flavor elements.

Are you grinding from a hopper full of beans or preweighing and grinding all the preweighed beans? The latter technique can be wildly inconsistent with some grinders. The MDX can tend towards a lot of retention with the big cross bar in the throat.

Allon, thanks, I grind about 15 gr, then with the portafilter on the scale I weigh 14.7g directly into the portafilter.
There is usually 200 g of beans in the hopper. Although at some point the hopper nears empty and the pop-corning starts.
The dosing chamber is always emptied.
Problem with this grinder is the ground coffee stuck in the chute. I must take out the the plastic plate at the top of the dosing chamber so that the chute can be cleaned out.

Yeah, I removed the top structure of my doser (the finger guard ring that hosts the auto-shut off and supports the lid) which makes the lid not fit so well, but exposes the chute so I can brush it out.

Though since I got a Pharos, it just hasn't been a problem....

another_jim wrote:

• As the weather changes, as the coffee ages, as the static charges on the grinder wax and wane, the ground coffee becomes fluffier or less fluffy, and also more or less compressible.
• These changes affect the density of the prepared puck.
• So, if you dose by volume, it will vary the weight of coffee you use from shot to shot.
• But the flow rate depends almost entirely on the weight of coffee.
• So if you dose by volume, you will see frequent changes in the shot's flow, and have to make frequent grind adjustments.
• Since these grind adjustments are retrospective and cannot anticipate how the ground coffee characteristics will change for the next shot; volume dosing will always be jittery, both in shot by shot flow rates, and in the compensating grind adjustments.

If you dose by weight, the jitters go away. Instead, the same dose from the same blend will always get you the same flow. Call this the principle of grind-weight invariance.

I haven't entirely been sold on the notion of dosing by weight (been doing a home made version of Scottie Callaghans barista tools), but this right just cleared it up. Ordering a scale right now.

I highly recommend this scale for espresso. It is by far the most responsive and fast updating pocket scale I've ever used, which is important for weighing shots. Be warned the 550g capacity makes it mostly useless for regular brewed coffee, though.