JimmiCliff Senior Member Joined: 29 May 2012 Posts: 11 Location: Toronto Expertise: Pro Barista
Posted Wed Jun 20, 2012, 10:40am Subject: VST Baskets and side-channeling
So i've been having some issues with side-channeling or rim-channeling - not sure what the proper term is - basically, when I look at the puck after a shot, there's generally a collection of holes (3 to 10) around the edge. During extraction, there's sometimes early blonding around the outside edge of the basket.
I'm using 20 gram VST baskets, dosing 19.5 to 20.5 grams from a k30, leveling with some curved plastic, getting extractions within normal time/weight values, tamping with a 58.4mm flat base.
fox2000 Senior Member Joined: 18 May 2012 Posts: 46 Location: WA Expertise: I love coffee
Espresso: Isomac Millenium I Grinder: Mazzer S.J. Auto & MDX
Posted Wed Jun 20, 2012, 1:31pm Subject: Re: VST Baskets and side-channeling
I unfortunately can't help you with this because I am having a similar problem with my setup. I can't figure it out it happens almost everytime. I hope one of the gurus can help us both.
Posted Wed Jun 20, 2012, 4:19pm Subject: Re: VST Baskets and side-channeling
I'm certainly no guru, but I've found that sealing the edge is rather important with the VST (which was pointed out to me by someone on CG). I've remedied it by using a bit of nutating motion. Since integrating that in, I really haven't gotten any side channeling.
JimmiCliff Senior Member Joined: 29 May 2012 Posts: 11 Location: Toronto Expertise: Pro Barista
Posted Wed Jun 20, 2012, 5:47pm Subject: Re: VST Baskets and side-channeling
I haven't tried actually nutating, but when I've been distributing with the plastic I've gone so far as to make exaggerated pushes out towards the edge of the basket, to the point of almost losing coffee over the edge, to make sure that there's a good amount of grounds out there. But I'll try nutating tomorrow.
fox2000 Senior Member Joined: 18 May 2012 Posts: 46 Location: WA Expertise: I love coffee
Espresso: Isomac Millenium I Grinder: Mazzer S.J. Auto & MDX
Posted Fri Jun 22, 2012, 3:02pm Subject: Re: VST Baskets and side-channeling
I have been nutating I am sure my technique is lacking as I am still new to this but I am also wondering if grind settings could be the problem? I am struggling with proper extractions I can get the time right and the taste good sometimes but even when I get those right I still get some channeling often side channeling. I am using a super jolly and a millenium so I doubt its equipment failure I am using 7day roasted paladino blend. I know I am making this all way to complicated but.... I am using WDT (partially) to break up clumps and spread, 17.7 dose, 200-202 f , and also the nutating motion after I spread the grounds using the stockfleth move attempting to make the sides more dense. Then I slide the convex tamper down the sides lightly to push grinds down and avoid tapping. I lay the tamper with no pressure in the basket to check evenness if its not even I gently push to even then I tamp 30-35lbs. The puck doesn't touch the screen prior to extraction but after I can see a slight indent of the screen in the middle of the puck. After all of that work I almost always get a little pin hole channeling and maybe 70% have side channeling? Any advice would be much appreciated.
fwtechwiz Senior Member Joined: 19 Feb 2010 Posts: 522 Location: Fort Wayne, IN Expertise: I live coffee
Espresso: Gaggia Evolution Grinder: Hario Skerton
Posted Sat Jun 23, 2012, 3:09am Subject: Re: VST Baskets and side-channeling
I've found with nutation, it's practice, practice, practice... Don't have any experience with the VST baskets, but I would assume since the VST is prone to edge channelling, the nutation move would need to be pretty extreme. Try maintaining at least a 30 degree slant on the tamper while nutating, rotating three or four times around. Lift the tamper, check the edge, you should see an upward curve. Ideally the tamper should be very close to almost touching the sides, if it's too small you will need to do a N-S-E-W tamp to get the edges tamped down. Otherwise, one strong tamp, straight down should do it.
fox2000 Senior Member Joined: 18 May 2012 Posts: 46 Location: WA Expertise: I love coffee
Espresso: Isomac Millenium I Grinder: Mazzer S.J. Auto & MDX
Posted Sat Jun 23, 2012, 1:54pm Subject: Re: VST Baskets and side-channeling
OK so I tried the nutating basically on its own with a quick clump break up because I had 1 large clump and a non pressured level. Low and behold I had my first drinkable shot in a while. Its funny when I first got all my gear I would get some pin holes and some side channeling but the shots would still be good. In hopes of fixing those small issues I created a ridiculously long routine that gave me horrible shots. I have come to the conclusion that using several distribution/ leveling techniques actually does more harm than good. Thank you for your help (reality check) :)
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