Does anyone know how much water is actually introduced to the group head with each lift of the lever?

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

dcupstateNY wrote:Does anyone know how much water is actually introduced to the group head with each lift of the lever?

It depends on the tamp to a certain degree. If your basket isn't full, more water is introduced. If the tamp is very loose, then water will come in easily and even saturate the grounds. If the tamp is very tight (to the point of being air tight), then the back pressure can keep water from coming in (depending on the pressure in the boiler).

Normally one pull of the lever will get you around 1 oz or maybe a little bit more. I can check it next time I pull a shot. However, again, it depends on several different factors; so it's not really a totally fixed volume each time.

Ray

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

Thanks Pat! That's exactly the info I was seeking i.e., volume prior to pulling a shot as opposed to anticipated/actual shot volume.

RayJohns wrote:It depends on the tamp to a certain degree. If your basket isn't full, more water is introduced. If the tamp is very loose, then water will come in easily and even saturate the grounds. If the tamp is very tight (to the point of being air tight), then the back pressure can keep water from coming in (depending on the pressure in the boiler).

Normally one pull of the lever will get you around 1 oz or maybe a little bit more. I can check it next time I pull a shot. However, again, it depends on several different factors; so it's not really a totally fixed volume each time.

Ray

Thanks for your input too, Ray! I've been following all your posts, and truly enjoy the vids ... very informative and

homeburrero wrote: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've got a Gaggia Factory with the pressurestat probably set on the low side to help with temperature management. I'll have to measure the flow rate to compare.

homeburrero wrote: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.

I'm usually dosing 14 grams and filling the group for 10 seconds before a pull for a double. I find that I get enough volume that I've never been tempted to do more then one pull. If I try and fill the group for longer then 10 seconds, I find that coffee will start to exit the bottomless portafilter into the cup, ending pre-infusion.

I was under the impression that doing a single pull on a La Pavoni was not typical, I'm wondering how many other Millennium users do just a single pull. I went from using a La Peppina lever with a 45 mm portafilter that is know for having one of the highest single-pull shot volumes so I was expecting to have to do multiple pulls with the Gaggia Factory, but it doesn't seem to be the case in my experience.

For singles, I dose 8 grams to have enough coffee to tamp and fill the group for only like five seconds. I'll have to make some measurements on shot mass to compare.

dcupstateNY wrote:Thanks for your input too, Ray! I've been following all your posts, and truly enjoy the vids ... very informative and

Thanks very much

BTW, I just pulled a shot of espresso and measured the resulting amount for you. The 49 mm double shot basket was pretty full (about 11 or 12 grams of coffee). Medium/fine grind and the boiler pressure was 11 PSI (my machine has a PID controller installed, so I can adjust the temperature/pressure in the boiler). Anyway, one full lever pull and the yield in the cup was (by weight) 30.9 grams (so 30.9 ml).

Almost exactly 1 oz.

Ray

yakster wrote:I'm usually dosing 14 grams and filling the group for 10 seconds before a pull for a double. I find that I get enough volume that I've never been tempted to do more then one pull. If I try and fill the group for longer then 10 seconds, I find that coffee will start to exit the bottomless portafilter into the cup, ending pre-infusion.

I was under the impression that doing a single pull on a La Pavoni was not typical, I'm wondering how many other Millennium users do just a single pull. I went from using a La Peppina lever with a 45 mm portafilter that is know for having one of the highest single-pull shot volumes so I was expecting to have to do multiple pulls with the Gaggia Factory, but it doesn't seem to be the case in my experience.

For singles, I dose 8 grams to have enough coffee to tamp and fill the group for only like five seconds. I'll have to make some measurements on shot mass to compare.

Thanks Chris for your input!

RayJohns wrote:Thanks very much

BTW, I just pulled a shot of espresso and measured the resulting amount for you. The 49 mm double shot basket was pretty full (about 11 or 12 grams of coffee). Medium/fine grind and the boiler pressure was 11 PSI (my machine has a PID controller installed, so I can adjust the temperature/pressure in the boiler). Anyway, one full lever pull and the yield in the cup was (by weight) 30.9 grams (so 30.9 ml).

Almost exactly 1 oz.

Ray

Ray, thanks again!

homeburrero wrote: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.

I tried this with my Gaggia Factory (equivalent to a La Pavoni Pro Millennium) and got ~45, 57, and 60 ml so 50 ml in six seconds sounds about right. My pressurestat is set fairly low (set by the previous owner) centered probably at about 0.8 or 0.85 bars.

homeburrero wrote: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.
- Pat

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.