dsc wrote:The lift of the lever is slow and I do hold it on the top for around 6-8sec, so there's plenty of time for preinfusion. I often leave it up till I see beads of coffee on the basket surface and then press down. I might play around with how heave the push down is.

Regards,
T.

You will get a lot of opinions on this - but I have found that just lifting the lever for 6-7 seconds does get some degree of pre-infusion, but it is many times partial and not always even distributed. That is why many utilize the Fellini (sic) method to aid in a nice, even distribution of water through the puck.

I also look for the beads of coffee coming out for an indicator of preinfusion - however, I only pull once those beads are consistently spread across the entire surface of the basket bottom - and I can only accomplish this using the Fellini method. Because I might tamp harder than some, just lifting the lever for pre-infusion - and no matter how long I lift it - will only partially infuse the puck, and only create beads across a small percentage of the basket. By gently pulling down until I see an even distribution of coffee coming out - even a drop or two - then I pull back up (aka Fellini) and then pull down. Some do this twice if they don't get the "feel" they have the right pressure, or are profiling differently for a new bean, etc.

Like you said, it pays to play with different methods to see what works best, just sharing what works best for me.

Thanks to everyone for all the suggestions and ideas, I will try these out as soon as the ZR is back up and running. It is indeed the prototype, but I keep messing about with it, so it probably spends more time in bits than it does assembled and running I'm finally moving it from the 'lab' to the kitchen this weekend, so hopefully that will end all the constant tweaking and pulling parts.

Rgds,
T.

Great... looking forward to hear what you discover to close out the thread with useful conclusions and data.

SpaceTime wrote:You will get a lot of opinions on this - but I have found that just lifting the lever for 6-7 seconds does get some degree of pre-infusion, but it is many times partial and not always even distributed. That is why many utilize the Fellini (sic) method to aid in a nice, even distribution of water through the puck.

I also look for the beads of coffee coming out for an indicator of preinfusion - however, I only pull once those beads are consistently spread across the entire surface of the basket bottom - and I can only accomplish this using the Fellini method. Because I might tamp harder than some, just lifting the lever for pre-infusion - and no matter how long I lift it - will only partially infuse the puck, and only create beads across a small percentage of the basket. By gently pulling down until I see an even distribution of coffee coming out - even a drop or two - then I pull back up (aka Fellini) and then pull down. Some do this twice if they don't get the "feel" they have the right pressure, or are profiling differently for a new bean, etc.

Like you said, it pays to play with different methods to see what works best, just sharing what works best for me.

I am pretty sure That is not actually a Fellini but is more of a pre-infusion pressure profiling. I would guess, when I do the same, it is probably around 3bar at the puck based on pressure charts I have read. The second lift probably wouldn't be necessary with a longer boiler pressure preinfusion followed by the higher pressure preinfusion, but it is something I have been playing with as well.

I am not personally aware of a formal definition of "Fellini" (if you have one please share) - but I agree that ultimately that any lever lowering / raising is ultimately pressure profiling to gauge if pressure is sufficient to continue with the full downward stroke.... but again, it is subjective, and based in what you might be trying to accomplish with a particular bean / shot (aka profiling)

Quick update on the problem, seems like I was indeed boiling the shots, I was getting some mighty sour flavors and thought it's down to low temps, it was the other way around. I've just quickly lashed this up:



and finally setup the pressure switch properly so the pressure in the boiler runs between 0.8 - 1.0bar, still I struggle after pulling the first shot as the temperature of the group easily exceeds 90degC. Anyone else with a Cremina struggles with the same? shots pulled at 80degC on the group are fine, but anything higher and it starts tasting pretty bad.

T.

You should install a thermal break gasket (between the group and the boiler).

That's a small investment for a man, one giant change in the temp behavior of your Cremina . It won't happen the first time.

I'll be soon switching to permanent control via a pressure transducer, just need the right controller sent from home as the one on the photo doesn't have an output as I've recently found out (to my surprise).

Is something cutout from a PTFE sheet good enough? I can easily get those from ebay.co.uk, just need to make sure I get the right stuff before something melts and I end up with a mess.

Rgds,
T.

Given how we can see the stream swirl and move around, despite the initial even beading, I would wonder if the bubble isn't caused by the liquid avoiding "dead spots". I've had what seems to be similar trouble and resolved it with improved distribution. The reason why I think it may contribute to the trouble is if you have sourness at high temperatures that seems to be more like an uneven extraction...

dsc wrote:Quick update on the problem, seems like I was indeed boiling the shots, I was getting some mighty sour flavors and thought it's down to low temps, it was the other way around. I've just quickly lashed this up:

<image>

and finally setup the pressure switch properly so the pressure in the boiler runs between 0.8 - 1.0bar, still I struggle after pulling the first shot as the temperature of the group easily exceeds 90degC. Anyone else with a Cremina struggles with the same? shots pulled at 80degC on the group are fine, but anything higher and it starts tasting pretty bad.

T.

Well SOUR would not be hi temps, it would be too low. Bitter would be too high. Generally.
My opinion is your distribution is off. Every one of your shots started around the edge of the basket and worked inward. You want to avoid that if possible.

I owned a Cremina for 5+ years. I found the Elektra MCAL double basket to give me much better consistency and sweetness, and NONE of the edge channeling.
I also do not believe doing a so called Fellini with a Cremina is worth the extra 5 grams.So many bad things can happen. My ,02 is that, wity 16 grams of coffee, a shot in a Cremina larger than 23 grams is not a true Cremina shot. (waiting for the incoming! )

Are you using rested beans? Are you doing a WDT? Not that you have to do the latter, but I found, due to the smaller 49mm basket, that reducing any clumping prior to simple distribution virtually eliminated any problems. I got NO air bubbles, squirts, spritzers, etc.
IMO, manual levers are very much dependent on a good, solid, simple technique. The less fussy, the better.
Perhaps a video of your prep routine would be educate us