Dan in Buyer's Guide to the LaCimbali Junior DT1 http://www.home-barista.com/junior-buyers-guide.html noted that "I learned that getting proper extractions from Junior demands that the barista pay more attention to technique, otherwise there's a risk of channeling."
I've had the (probably 10 year old) manual vibe Cimbali Jr S/1 for about 2 weeks now, and am still learning about it. When I was testing the Cimbali Jr grinder that came with it, I got a bit of channeling, but thought maybe that was just the grinder, since the Macap never channeled. But this morning, with the Macap, for the first time, I got a sprite. I do know that I was a tad careless this morning leveling after doing Stockfleth, but.... Incidentally, the cimbali jr grinder produced some superb ristrettos.
I've also noticed that may times it will take up to 10-15 sec from start of pull before I get a single stream. (7 sec before any drips)
(once I got the temp straightened out by removing the insulation that I had added, the taste has been great!)
I am using the EPNW "synesso" basket (flat bottom, bottom a bit smaller than top). http://espressoparts.com/product/W10813
I think my first tamper was a Lava convex that I used for a while on the Silvia, and gave away with a Rocky I was selling - replaced it with a 1-st line rosewood flat tamper. If I recall correctly, I got more channeling with the convex than the flat, with Silvia. While I was using the Solis exclusively, I used a RB flat tamper (53) that I loved because it was a bit shorter than the rosewood 58.
So if I get a new tamper, I may very likely get a new RB piston and use it on the blue handle that now has the 53.
I have looked many times through HB Tamper Roadshow, and searched a bunch, but not found anything definitive on convex vs pour.
When I first got the new S/1 head gasket and first started pours, the results were superb. This changed at least partially because I unlocked and adjusted the OPV from 14-16 to 9.5 . (Apparently USA models have the OPV locked closed while European models OPVs are used normally.) This necessitated a more coarse grind. And with it came the channeling. And with that came the hesitancy of the pour streams to coalesce. So one thing I will certainly play with in coming days is upping that pressure and watching taste and pour.
The question of this thread, to folks who have used convex tampers (slight, or moderate, or extreme), is, would a convex tamper help the (non-pre-infusion) saturation of the puck in a way so as to possibly/likely help avoid channeling and encourage coalescing of the pour streams?
Thanks!
, just kidding)
