schneckerl wrote:I guess it's always preferable to fill it up to the max and to stop the pull according to preferences. More water = higher temperature.

Hence the question of whether there's a marking line in the basket, like in the Flair. Which would also help with comparability. Would also allow avoiding spillage or damage to shower screen.

Just a quick response for the moment. Basket volume is 120 ml for both pro and pressurized. There's no marking line. Paul suggests filling a bit shy of the top by 6-8 mm to avoid any drips before the piston seals into the basket.

I've always struggled with water temp at my elevation - on the mypressi as well as the espressoforge. I like that the robot has less metal mass to draw away heat, relative to the mass of water that the basket holds. Here is how I would preheat for light roasts: prep the basket, insert it into the handle and add the filter screen. Then shoot into the basket with my $10 heatgun for 10 secs. before adding water just off the boil. Tested, that is enough time to get the metal too hot to touch on my empty smallest milk pitcher so should work well on the robot, and is less messy than a water preheat. Not the most aesthetic, but quick and efficient.
Rich

Balthazar_B wrote: So FWIW my hypothesis is that best practice will be to always fill the portafilter to the same constant level and go from there.

I guess it's always preferable to fill it up to the max and to stop the pull according to preferences.

+1000

That is what I suspected too, but thought about asking anyway (out of curiosity).

It is good to leave some clearance also in order to have some air between relatively cold piston and water, to avoid cooling the water with piston. With Flair, I usually fill it up to 1-2 mm below the line, so there is no unnecessary touching the water with plastics, which happens if the water is over the line

On the other side, less water means lower thermal mass and worse temperature stability

Balthazar_B wrote:Sam or Gary, just curious. Are the portafilter/basket components ferromagnetic, by any chance? You can guess why I ask...

I was wondering how could I test that and voila, the chute of the Monolith does stick to the basket & pf (albeit weakly). There your answer. But really I don't think there's a need for that (if I had guessed correctly what you intended to do with that information)...

Javier wrote:For a given dose, do you need to add a predetermined volume of water in order to obtain a desired mass of espresso?

That's a great question...I have been pondering myself if there's any benefit to fill with less-than-maximum water capacity.. I can see three - (i) it''ll be slightly easier to apply pressure (as the lever will be engaged lower) (ii) no need for an additional catch tray if you fill in the exact amount of water (iii) less chance of spilling water from overfill. However, I do not know if that has any effect on the shot. Guess there's only one way to find out.


At the moment the basket does not have any marking indicator/line. The Robot is not super fussy about water level from what I can tell. But I agree it'd be nice to have them if it's feasible for Paul to do so.

Balthazar_B wrote: Are the portafilter/basket components ferromagnetic, by any chance? You can guess why I ask...

As Sam said, they are mildly magnetic. A refrigerator magnet will stick to them. But not very strongly, not at all like my stainless knife blades. I doubt you can stick them to a magnetic knife bar for storage. And my induction cooktop fails on them, so if you were thinking of using that to pre-heat them, it probably will not work.

homeburrero wrote:As Sam said, they are mildly magnetic. A refrigerator magnet will stick to them. But not very strongly, not at all like my stainless knife blades. I doubt you can stick them to a magnetic knife bar for storage. And my induction cooktop fails on them, so if you were thinking of using that to pre-heat them, it probably will not work.

That was it. I was thinking of ways one could do a dry preheat of the components fairly simply, if one wanted, particularly for the first shot.

I'm not sure that many induction cooktops would work even with suitable metal of diameter around 5 cm anyway. Usually low limit is something like 7cm for smallest coil, at least those sold here in Europe. Ok, PF is more than 6, but it's just the rim

Whether or not the portafilter basket is magnetic you can always put it dry in a pot that is heated on the stovetop. I have small cast iron pans that fit the stovetop small burners and are suitable for heating things like this or my Atomic or Vesuviana coffee makers.

Nespresso used to have a mill frothed that was induction based. The advantage that it is low power so would heat the filter (assuming it is ferromagnetic.

I took one I found in the dumpster apart to convert it to a cup warmer with a tin can.