Here is the best explanation I have found. Rather than llink to it, I am pasting it. It is from Kurt August from last year in the Arrarex Caravel thread, page 105.

"Michael B. informed me that the earliest models have two rows of water inlet holes, instead of one row on the newer models. This reduces the volume of the closed chamber, hence the lower shot volume. Sounds logical to me."

What doesn't add up about that quote is the closed chamber that matters is below the lowest row of holes, isn't it? Now there may be something about how rapidly water gets pulled into the piston chamber with one row of holes being squeegeed rather than two. So what happens if you give the raised lever longer to fill? Are the shots still smaller? And with these machines wouldn't multiple pulls provide the volume you want as long as you're using the same dose?

I just modified my MCAL with a longer piston rod that slightly reduces the travel of the piston because the upper end stops the lever from going vertical and almost pushing out the shower screen. This stops the shot at a beautifully tuned point, but if I want the old volume I just add a half pump midway through.

Out of curiosity, what size basket are you using? I usually dose 16 grams in my double and do 2 pulls with 1 pre-infusion pull. You pic looks like what I pull with my smaller basket with about 12 grams. I've noticed that if it's low in water, the lever feels spongy and the shot is smaller.

Gary and Jess,

I think there is something about getting the air out before pulling. The spongy feel has gotta be the trapped air impeding my extraction. I will keep working on it. In Doug's original posts when he got the machine, he talked about waiting for the gurgle to stop and then wiggling the lever to get all the air out. I have tried that, but to no avail thus far.

Jess, I am using the standard double basket and dosing 15 grams of Redbird. That pretty much fills it up even after tamping. There is just a tiny bit of headroom after a leveling tamp (thumbs only).

I do have the bigger straight-walled double. I haven't used it yet. Maybe I will give that a try and do a triple pull! But I think the real answer is getting the air out of my way first.

Does anyone out there have the two rows of holes in their kettle like me? What do you do?

Off for a decaf session.
Pete

PROGRESS!

I took off the kettle lid before starting my pull to see what was going on with the air. I raised the lever and tried to figure out what Doug meant when he said he wiggled the lever a few times to get the air out. By watching the water I could see that four or five very small pumps back and forth will work the air bubbles out. By small pumps, I mean probably two inches back and forth at the top. Now this totally makes sense to me. I tried my usual routine after that, which is to pull until a few drops come out, raise the lever (do a couple more small pumps), and pull through. It looked like I was getting closer to my normal volume shot. I then did a second full pull and kinda ruined the shot. That would be normal with my old gear as well. Thought I would give it a try. Jesse, I know you said you do two full pulls. I have never had much luck with it.

But - the point is that I know how to work the air out now and can now resume my pursuit of the perfect shot.

Pete

Nice!

I've also done partial pumps to work water into the puck. But recently I just waited longer with the lever raised and allowed water to infuse the puck. That created a very nice pull. Have you seen how long you might need to wait to let gravity do its work?

Just a quick update.

Since figuring out that short partial pumps work out the air that is trapped in the group cylinder, I have found my groove. I am now getting extra tasty shots that are in the normal caravel volume range - small, but POW.

When I raise the lever the first time, there is an audible gurgle of air rushing out. It stops after about a second or two. With my Red VAM, that is all I need to wait for and can then start my normal pull (pull until first drops, raise and then pull all the way through).

On the OE VAM, after I raise and wait for the gurgle, I need to do three or four partial pumps, then pull until first drops hit the cup. Then I raise again, one or two more partial pumps, then straight through. I can really feel the piston engaging resistance with little or no spongy feeling. Lovely espresso starts streaming a lot sooner than my futile efforts before I discovered the lever cha-cha.

Am still going to try to get a spare kettle with one row of holes in play, but don't have the sense of urgency as before.

Pete

Nice.

Have you tried raising the lever and waiting a bit longer without pumps? Just curious to see if that works too.

Hey Gary,

Yes, I tried just waiting a bit longer to see if the air works itself out. It doesn't. My dismay in the first days was because it seemed that the initial gurgle was all the air rushing out as on my other machine. I now believe that somehow the top row of inlet holes somehow allows some air to be trapped and only a small push of the lever will work it out.

On that note - off to have an after dinner decaf or two. Cheers!

Pete