homeburrero wrote:Hi Dave,
I see that no-one is replying, and think that's because it's a little unclear what you are asking. The grouphead fills only while the piston is at the top of the stroke on a typical millennium, and the volume would depend on how long the piston remains up, and on other factors if you have a loaded basket. Also would depend on the setting of the pressurestat and on the tightness/age of the lower piston seal.

I've measured the flow rate on my millennium: At peak pressure (right after the light goes out) and with an empty basket it delivers 50 ml in 6 seconds with the lever held at the top of the stroke. I'm not sure this is typical, but it seems to work. With a 16g dose, tight grind and a 12 second (that's long) pre-infusion (no Fellini moves) I'm getting around 22g of liquid (roughly 1.5 fluid oz of volume, depending on crema) from a single pull.

Unfortunately I don't know what my pressure is (need to buy a gauge someday)

P.S.
There is only one inlet hole on the millennium sleeve, and it's right against the lower piston gasket at the top of the stroke. When I realized this I stopped doing Fellini moves -- I figure that holding the piston at the top most effectively allows water in (and air out, since the gasket is relatively unsealed near the inlet hole.) If I pull too soon, I get less volume and feel the squishyness of far bigger air cushion.

Hope this addresses your question; I'm curious about other millennium owners' volumes.

- Pat

homeburrero wrote:Dave,
What I measured was the water delivered to a cup beneath the empty PF. I raised the lever at 0 seconds and held, then lowered right at 6 seconds. I should say that this is the rate that water delivered to the cylinder. This to me is an interesting measurement as it's somewhat of an indication how fast and hard the water hits the puck in the pre-infusion. I think slow is good, but suppose that's open to debate.

In the millennium, you also have water (and air) inside the group that is outside the cylinder. I have no idea how one might measure this.

yakster wrote:This I measured only once since I was drinking my homework and due to the lateness of the hour. I pulled a shot with 14 grams of Handsome Coffee Roaster's espresso with a ten second pre-infusion which resulted in a 30 gram shot. I did not measure volume as I pulled into ceramic. With a shot mass like this, I really see no reason for multiple pulls.