Hi Paul,

Just want to say thanks for posting here every so often in response to matters people raise. Don't see that very often! I have been following this thread for some time now and have always appreciated that. Can't wait for your device to arrive!

Paul_Pratt wrote: If you have a barista version the air goes up the tube and then gets compressed.

Hi Paul,

Is it just air that goes up the tube to the gauge? I was thinking the other day as to what would stop the water from g ing up the tube. Is this what that filter is for, to keep coffee solids from getting to the gauge??

I ordered a robot at the beginning of this week from Cafune in Canada. Should be here in a day or two, I can't wait!!! Justin mentioned that the new screen is included in the box, what about the new twist on gauge that I saw you mention, Were they sent out with the units that have the new screens?

Can't wait!!!

Ken

On my Robot, coffee solids started going up the tube after a few weeks of use. It's basically fines and mostly clear water, perhaps possible to adjust the tube, but it doesn't reach the gauge so I haven't bothered (figure it'll happen again eventually anyway).

Looks a little untidy so some day I'll buy the metal tube to cover..

Jonk wrote:
Looks a little untidy so some day I'll buy the metal tube to cover..

Doesn't the Robot barista come with the metal sleeve over the plastic hose?

Does now but didn't originally. Been meaning to add it to mine.

Ken5 wrote:Is it just air that goes up the tube to the gauge? I was thinking the other day as to what would stop the water from g ing up the tube.

The air pressure keeps it from going too far.

It's a little bit complicated. If you applied 10 bar pressure you'd expect air to be squished down to 1/10 the volume. But it isn't just air in the space above the basket. The vapor coming from the hot water will push a lot of that air away. If it were 100% water vapor the piston would cause it all to condense leaving no head space at all. But it's going to be a mixture of air & water vapor. I tried to measure this once and got 50/50. So anyway, when you apply 6-8 bar pressure most of that water vapor is going to condense. The remaining air will compress to 1/6-1/8 it's original size. Well, some small amount will be pushed into solution as well.

So a 1 cm head space of 50-50 air/water vapor mixture at 6 bar would probably compress to roughly a millimeter in height. In the pressure tube it's going to be mostly air but the volume in the tube and fittings is less than 5% of the total volume (assuming you fill to ~1cm from the rim). So it won't make that much of a difference.

Well, that's what I imagine anyway. I'm curious what the initial head space was in that transparent portafilter video.

When I removed the pressure tube on my Robot it had just a bit of discoloration in the first few centimeters.

I've bought the new metal filter screen from Prima Coffee and I'm loving it so far.

• Easier to clean since there's no lip underneath to catch grounds
• Easier to preheat since the silicone isn't slippery and doesn't get hot
• More robust because it's thicker metal and there is no risk of pin damage
• Can be used as a tamper since it's flat!

I think a sub $300 option for buying a Robot with no tamper would be really attractive to those who end up going with the Flair for budgetary reasons. Of course this would require an extra line in the manual about using the new screen to tamp gently.

Got mitts for Rob today, didn't really think I needed them but with some experimenting lately I found that harder pulls were needed.
The extra stress relief from these things is most welcome.

My wife bought me a pair of the Robot Hands. They protect my eyes when the Robot arms are fixed in the up position (when she sees that she always says "Stick 'em UP!"). But I'm not finding them any more comfortable when pulling a shot. Actually, they're less comfortable. They look nice though so for now they stay. Maybe I'll get used to the way they feel, just like I did with the claws.

Huh, there you go; different strokes et cetera.