Just wondering:
Can Cremina owners report on how much water is released per pull on their 67 Cremina's?
This would be with an empty basket, an upstroke, then an immediate pull downward, no waiting. I do this flushing generally 3 times before grinding my first shot, to get the group temp up.
I then "cheat" the Cremina by flushing through the group one more time before inserting the PF and filled basket.
I'm just curious as to how much water should be coming through. I do an 8 second hold at the top (no Fellini move) before pulling the shot, so I expect more then the flush amount of liquid.
Thanks.

It doesn't really matter (i.e. volume is not affected by) how long you hold the lever up, unless the water is flowing through the coffee in the basket into the cup. The coffee in the basket dams the flow (except for what it absorbs). The volume of the piston cylinder is the volume of the piston cylinder.

timo888 wrote:It doesn't really matter (i.e. volume is not affected by) how long you hold the lever up, unless the water is flowing through the coffee in the basket into the cup. The coffee in the basket dams the flow (except for what it absorbs). The volume of the piston cylinder is the volume of the piston cylinder.

OK, so your sying if I raise my lever, than immediately begin downstroke for a warming flush, my amount should equal yours? makes sense.

Next time I have mine warmed up and ready I'll do this just to see what mine is cranking out. Later!

I have to agree with Timo on this ..the time you wait can effect swelling of the puck, extraction, and the time it takes to pull the shot- resistance etc...but volume should remain pretty constant..

The only small variable is the initial water loss to absorbtion to the coffee. That is why I susally let my hand rest on the lever after first raising it.. just to get most of the intial saturation out of the way.

get a drip or 3 in the cup.... then raise and pull away.

With crema height- about a 2/3 or 4/5 of a standard espresso cup....

Howdy, Greg

Rob, I never pulled a warming flush on the Cremina, but your understanding of the volume is correct -- the piston cylinder fills when you raise the lever and hold it up. Of course, with no PF in place, if you were to raise the lever only part of the way and let only a little water dribble out before pulling the lever down and closing off the port, the volume of water in that flush could be less than what the cylinder holds.

P.S. You must like higher brew temps. I think with all the flushing you'd end up with a fairly hot group. On your 8-second flush, does the water at first flash-boil and then become a defined shower-stream?

timo888 wrote:Howdy, Greg

Rob, I never pulled a warming flush on the Cremina, but your understanding of the volume is correct -- the piston cylinder fills when you raise the lever and hold it up. Of course, with no PF in place, if you were to raise the lever only part of the way and let only a little water dribble out before pulling the lever down and closing off the port, the volume of water in that flush could be less than what the cylinder holds.

P.S. You must like higher brew temps. I think with all the flushing you'd end up with a fairly hot group. On your 8-second flush, does the water at first flash-boil and then become a defined shower-stream?

Only slightly. The thing is, using the rental gauge from Orphan, I sussed out the behavior of my Pstat...I wait till the middle of the cycle before pulling.
The group is cool until after 2-3 flushes, and a 1 minute wait pd.
As you know, the Cremina is somewhat notorious for 1st pull sink shots (in my case, "spousal Americanos"
Funny you should ask! From Orphan, I just purchased the $4.95 liquid crystal temp strip devised by Richard Penney, and stuck it on my group. It is designed to tell me the outside temp of the group.
I will report back as to it's temp after a 2-3 flushes and the wait. Obviously, if it reads (in c/f) way higher than should be, out comes the cold towels.
Now, I just have to figure out the differential between the inside of the group & the outside of the group.
My guess would be that the basket has cooled, due to the grind now resting in there, and the PF has cooled slightly (by design)
So far, I've had no "dark ring" around my shots, usually a sure sign of overheating (?)
BTW, I appreciate all the feedback. Lousy subject thread, great responses.

My Cremina didn't produce a sink shot with the first pull; that was more likely to happen on the third shot, from overheating. The pstat was set @ ~0.8 bar. Where do you have yours?

I never took the temperature of the surface of the group bell.

And yes, the dark ring is a sure sign that the brew temp was too high. But tiger-flecked crema, as pretty as it is, can also be a sign that the brew water was too hot.

T...most of my shots have a bit of flecking, but don't seem bitter.
My first shot, even with a couple pre flushes, and the 1 minute wait (I grind, load in that minute) usually is a bit cool, and bordering on sour.
My stat is set to about .915 at the max, and .8 at the low point just before the boiler light comes on.(based upon gauge readings. I allowed the boiler to cycle 5 times while observing, and the gauge reading was identical all 5 times.
I usually pull my shot somewhere in between.

You're fully purging the false pressure? How long after the purge do you wait before pulling the first shot?