Hello everyone, my first post after reading lots of threads and articles.

I bought a Bezzera Unica (E61/PID/SBDU) with a Macap m2m two months ago and have been trying my luck since. After some initial trouble I have bought a calibrated tamper, a bottomless PF and a couple of yoghurts. The bottomless PF did then reveal that my shots suffered from a one-sided extraction, with generous channeling and blonding on the side opposed to the handle (the 'machine side'), and hardly any flow from the side of the handle itself. The position of the channeling never changed, not even by filling the PF from a different side.

I get a reasonable extraction now, holding the tamper close to the 'machine side' of the basket and pressing at a whopping 10°, leaning towards the 'machine side'. While I can enjoy my espressi at last, I'm still wondering what the trouble may be. I'm certainly not overconfident in my barista skills, but to imagine that my rubbish preparation needs a 10° tamp to get it back on track is a bit too much to swallow. Can anyone offer some advice on this one?

I think basket prep matters more than the tamp. Have you tried wdt? If you haven't a quick search on this site will tell you lots about it. I use wdt with a bent paper clip and get even extractions my e61.

After you've tried that, you might also look into a nutating tamp. You'll hear different opinions but I find that when I have a very light roasted coffee that's prone to channeling, it helps me to get a visually perfect extraction. Again, I'd focus on basket prep much more than tamp until you have that sorted first.

Hello Hudson, thank you for your reply. I use WDP (hence the yoghurts), two taps on the bottom, but I don't 'nutate' the tamper so far, although it may have a similar (positive) result to the shortcut I do now. I'm sure I could do a better basket prep which might change things a bit.

For the tamping technique, to rephrase it, I hold the tamper at a 10 degree angle to the PF, meaning that the surface of the puck is angled at roughly 10°, with the 'machine side' of the puck being the lowest and (I guess) more tamped. To a sane onlooker it's the most ham-fisted, uneven tamp you could imagine, but it's the only way I have managed to pull a decent shot.

For the time being I'll try to nutate the tamper!

Make sure that your machine is perfectly level.

That's what I've tried before comming up with the angled tamp. The machine is now standing on the kitchen floor, just in case the 50s Formica table isn't level (though it pretty much is). The same problem still occurs with a level tamp, and I get frequently reminded to sweep the kitchen floor. IIRC, when I tried heightening the rear legs of the machine, the result was much the same.

A quick update to my last post:

I found a suitable wooden cupboard (not a full height one of course!) to use as a work surface for the machine and grinder, though not for tamping. I started by taking a spirit level to the bottom outside rimm of the group head and adjusted the four legs till level. The front ones needed quite some raising, ~6mm for the right one and ~3mm on the left! I checked the cupboard, the main casing of the Bezzera and then the cupboard again, they were all level. It looks as if the bottom frame of the Bezzera had sagged or taken a severe hit. I won't take it to the dealer for now, the chances of having this fixed under warranty is about nil (no chance of proving that I didn't drop the thing myself), I'll rather get back to pulling shots and make up for lost time.