Hello,

I have just invested in an Isomac Zaffiro after 14 years with a La Pavoni Professional. With the Pav I was regularly able to get decent short-ish shots, but with a lot of variability which I mainly ascribed to temperature. The plan with the Zaffiro is to really hone my technique and produce stellar coffee on a regular basis... and I was hoping my years with the Pav had given me a good basic technique to start from. But...

So far, I have not been able to get a shot to run more than ~20 seconds and around 25ml before blonding. Past the blonding point there is a lot of bitterness as you would expect.

I have taken the grind down much finer than I ever did with the Pavoni, which surprised me. I'm using a Mazzer Mini E, and for the Pavoni I was generally grinding several notches finer than the factory setting shown by the sticker. I expected to be going coarser with the Zaffiro, closer to "normal".

I've systematically varied dose and grind and kept notes. Any coarser on the grind runs way too fast, and I am reluctant to go finer because the 20s/25ml shot seems like a slow flow rate already. I just wish I could get a longer pull before blonding.

Other symptoms and signs:

-- I'm getting wet pucks rather than the solid, dry things I was used to from the Pav
-- the brew pressure meter is riding up to about 11bar or a little more during the shot

Could my problems be caused by old coffee beans? They're 16 days past roasting, but the very same beans with same roast date are still brewing up a storm at my local cafe (maybe I stored them less well?). I can't get hold of fresh beans for a day or three so I can't test this hypothesis yet.

What other technique flaws might cause these symptoms? I'm definitely struggling a little with distribution in the double basket, which seems HUGE to me at 58mm after years with the 49mm Pav basket! Dosing below the rim is not easy for me at all, and filling the basket takes me to about 21g which seems too high a dose.

This is getting long now, so I will sign off, and look forward to all and any hints and suggestions you might have for me! Thanks for reading...

Welcome to HB anonymous!

11 bar brew pressure is too high. It should be reading 9. That may account for early blonding. Do you use bottomless portafilter? If not get one since that will help you a lot diagnose what the problem is. Blonding and fast shots can be attributed to channeling as well and naked portafilter will help you see that.

Water on top of the puck is nothing to worry about. Just means if needed you could increase dose.