Terrible side channeling caused by WDT?

[jeffg]

I can pull somewhat acceptable shots with a single basket, it's hit or miss but i am trying to work with the WDT since my grind can be a bit clumpy (mazzer mini, domobar super). For some reason the doubleshot is IMPOSSIBLE for me no matter what I try, i almost always get a massive gusher with bad channeling indication around the edges. I tried weighing my coffee from 16 up to 18 gram, wdt leveling tamping, etc. I just had an autotamper show up today and thought this might help but it's just as bad using the autotamp. If i do not use wdt i think i get clumps that lead to channeling, if I use wdt when i take the cup out there is a gap around the edges and various methods to fill the gap such as wrapping on the counter before leveling, pushing with finger nsew or pencil. It's always the same a big gusher with a noticeable side channeling gap on the edge. I am not sure what else to try. I've gone through bag after bag trying a huge variety of things and I just get nowhere. Tag me as worst home barista in history.. sometimes I feel I'm like a 1 armed blind man trying to play golf. Maybe i'll try the fleth move, that should be a sight to watch..

[Grant]

Sounds like a coffee problem. How old are the beans, and how long before your shot are you grinding them?

Also, how old is the Mazzer...any chance the burrs are shot?


Grant

[jeffg]

Well, i tried something different and it's working so far. I dose into the basket with the cup attachment, do my wdt only this time after i remove the cup I use the fatter than normal round pencil to push down on the top of the coffee stack from front to back sort of a gentle mush/mush/mush lightly pushing the grounds down, then i use the pencil to do a nsew leveling. Had close to 2 god shots in a row (my new autotamp may have helped a bit too). The wife was having a mouthgasm I just hope it wasn't a lucky fluke. I still have not attempted this on the double basket maybe tomorrow..

[jeffg]

Well, looks like a got lucky, just pulled 2 more singles 1 probably would have been ok but i over-extracted it. The second blamo huge side channel. I think i have every aspect covered except dosing & pre-tamp. I have good beans, good grinder, right grind setting, consistent tamp with the autotamp, brew temp sussed, etc. My weakest link is when the grinds go into the basket and what happens after that. I may try WDT + that fleth move hmm... Got any suggestions hit me..

[HB]

For some reason the doubleshot is IMPOSSIBLE for me no matter what I try, i almost always get a massive gusher with bad channeling indication around the edges. I tried weighing my coffee from 16 up to 18 gram, wdt leveling tamping, etc.

Try dosing less and grinding finer, e.g., 14-16 grams. Also confirm the brew pressure isn't wandering due to a faulty OPV spring as Randy reported:

The new spring, on the left, is much heavier than the original that I removed. The difference can be seen here, and compressing them between index finger and thumb reveals a great difference in compression force as well, with the new one being far stiffer.

Replacement is a simple matter of unscrewing and removing the adjustment screw, removing the old spring with a small tweezer, and replacing it with the new spring. Screw in the adjuster and Vito's your barista (Bob's your uncle?).

Once I had it all back together I inserted the blind filter and readjusted the OPV. I found that the new spring made it MUCH easier to adjust. The original was very touchy and the smallest adjustment made a large difference. The new spring was very linear in its adjustment and finding the desired setting was a very easy matter. before closing it up I turned the pump on and off a few times and every time the pressure gauge hit the exact pressure I had set.

[jeffg]

Thanks for the info. I a pretty sure i have the right spring as my pressure never wanders, with the blind filter it hits the exact spot each time and holds steady. I suppose I could check but it doesn't look easy getting to it. As for dosing less and grinding finer that would likely have the grounds mostly below my basket edge so how do you distribute the grounds when it's like that? Do you just tap the basket around until it's level then tamp? Thanks!

[jeffg]

well just pulled 15 more shots trying all manner of settings techniques etc, how many good ones did I get? 1 and barely good. When i tried to replicate what I did on that one shot I got a 5second gusher. I am now giving up and will not touch my equipment again until I have formal barista training. I'm currently trying to find a 2-3 day course of somekind. Very low spirits right now ugh.

[Randy G.]

........As for dosing less and grinding finer that would likely have the grounds mostly below my basket edge so how do you distribute the grounds when it's like that? Do you just tap the basket around until it's level then tamp? Thanks!

It sounds like you are using too much coffee. That can be a real problem. Try about 14-15 grams. Don't fill the PF.

If you have a gram scale, try weighing some GROUND coffee. Start with about 15 grams. Then pour the coffee into the portafilter. This will give you a good idea as to how much to use.

In daily use, as you grind, move the portafilter about to get the coffee distributed as evenly as possible while you are grinding so that further distribution is not very necessary. Once you have the correct amount, shake the PF about a bit to level as much as possible. You can use the WDT at this point if you wish. At this point, if the coffee seems uneven I will tap the PF STRAIGHT DOWN to pre-compress the grounds, or if the difference is slight, I will just jiggle the PF to level. Now tamp and lock. Remove the PF before beginning the pull. The coffee should NOT have contacted the screen.

You can also do the nickel test- place a nickel on the coffee and then lock the PF in place again. There should be no more than the slightest indentation from the nickel. if the coffee was disturbed beyond that, you used too much coffee for that basket.

[cafeIKE]

Sorry to hear you are having so much trouble. I swear that several, untrained home baristas have pulled great shots first time out on my Vibiemme, so let's see if there is something amiss.

Please review http://www.home-barista.com/forum...p-guide-t3113.html

By side channeling, I assume you get a big blond gush out of one side of the basket

- the machine should be on for at least 45 minutes, with PF in the group
- boiler pressure ~1bar, 0.9 to 1.1 is normal
- when you lift the lever with no PF, there should be steam for just few seconds, then plain water
- brew pressure about 10.5 on a shot and should not vary, except a little with the heater element
- coffee should be from 4 to 8 days from the roaster drum

If you flush to rinse the screen, do it just before you pull the shot. This will prevent thermosyphon stall.

The most common problem I see with noobs is an uneven tamp. Use your fingers as a gauge around the tamper and make sure the tamper is level. IMO, the AutoTampers apply WAY too much force. The one time I tried them, the missus asked what all the clacking was about. A light level tamp is all that is necessary.

Try 15g and level just as Randy said. Adjust the grinder for 60ml in 30 sec.

[Grant]

I think i have every aspect covered except dosing & pre-tamp. I have good beans, good grinder, right grind setting, consistent tamp with the autotamp, brew temp sussed, etc. My weakest link is when the grinds go into the basket and what happens after that. I may try WDT + that fleth move hmm... Got any suggestions hit me..

Still think it is your coffee....what is the roast date of the beans you are trying?

Sounds like exactly what happens if I use stale beans....no amount of fiddling with distribution, tamping etc. helps.

With your Mazzer grinder and a 14g dose with fresh beans, you can practically "toss" the grinds into the basket without ANY distribution and tamping and get a decent shot.

http://www.home-barista.com/forum...luation-t4501.html

If you have gone to all that muss/fuss and are still getting channeling, it has got to be old beans.

Grant

[jeffg]

they are supposed to be good beans from a local roaster, a local cafe gets them in every tuesday they are roasted on sunday and delivered to the cafe on tuesday and it's what they use as well. I guess I can try another roaster to see what happens. When you guys dose 14g do you actually get a puck? When I tried finer grind less dose, still 30lb tamp I got a puck that was soaked and sloppy it almost just slid out of the handle into the knock box.

I have a feeling espresso making is a heck of a lot like golf. I played golf for a few years and can imagine going out with the best clubs made and hitting it into the dirt. Then going online and everyone saying things like "sounds like you didn't keep your head down" "what grip did you use?" "keep your left arm straight" etc. In the end I quite likely just need someone there to say.. 'ah, this is what you did wrong' or 'ah, these beans are crud'.. I just feel like for every problem there are 50 answers and solutions. Anyway, I just contacted an espresso school about 45mins from here. They offer 2 day barista courses so might give that a go..

[jeffg]

If you have gone to all that muss/fuss and are still getting channeling, it has got to be old beans.

I tend to consider myself Murphy's Law in human form so who knows!

[jeffg]

i'm about to take out my pressure spring just for peace of mind.. will report back

[jeffg]

i'm about to take out my pressure spring just for peace of mind.. will report back

Definitely the fatter stronger spring upon examining it.

By the way these are my machine adjustments. With the blind filter on and letting it peak my boiler reads 1-1.1 and my pressure reads 10 (which from what i hear translates to 9 or so on the puck?). It would be good to know what I would see if these setting were not correct (can i trust these gauges?). What would I get if the boiler was too high and the brew too low or both too high, brew too low boiler too low etc..

[HB]

For some reason the doubleshot is IMPOSSIBLE for me no matter what I try, i almost always get a massive gusher with bad channeling indication around the edges.

Your reports are puzzling. In closing out the Vibiemme Domobar Super review, I pulled some final espressos over the weekend. It was a breeze to pull long, evenly striped extractions using a bottomless portafilter. I dosed with 15 grams and confirmed no puck contact with the dispersion screen by locking in/removing.

Maybe your brew pressure gauge is just plain wrong (?). You've got nothing to lose, try dropping it to 8.5 bar; the lower pressure will give you a wider margin of error.

[jeffg]

Maybe your brew pressure gauge is just plain wrong (?). You've got nothing to lose, try dropping it to 8.5 bar; the lower pressure will give you a wider margin of error.

So it says 8.5 on the dial when peaked with blind pf right?

[HB]

Yes.

[cannonfodder]

I have been using 15 gram doses in the VBM for some time, I find that works about best for my coffee selection. As to the puck, because you grind finer with a lower dose, the puck tends to be more "sand on the beach" looking on the top.

That side channeling, is it the same side every time? I had a hard time with side channeling, and even still get a lopsided extraction. I just favored one side of the tamper when tamping. To remedy, I grind a little finer and tamp very light, I would guess 10-15 pounds just to level the dose and make sure it has even density. I also give the portafilter two or three downward thumps on the tamping stand to settle the dose before I tamp. But do not thump too hard, a one or two inch downward thunk is sufficient.



Notice how the cone is favoring the front of my shot, the front started to flow before the back. Is you issue similar?

[jeffg]

Whoa whoa whoa.. I got so much advice here I decided to buy another bag and retry my efforts. This coffee came from a different cafe which I had never been too. The claimed it was roasted 2 days ago so I brought it home. I reduced my pressure to 8.5-9 bar, i also let the machine heat up for an hour. I ground my new beans, did my flushing to get the right temp while wdt and tamp, I went back to using my finger nsew for distributing. Locked, pulled and holy cow a perfect rich stream appeared and it stayed rich until the very end, the result was glorious and unlike any shot I had pulled before (this makes me think my last beans were crud like some had suspected!) The cappuccino was very very nice. The beans have a complex taste with nutty undertones which aren't my preference but hey i got a good shot. I'm pulling two more in the morning and will report back in, if they turn out well I'll be stoked. However this is still from my single basket. Now can someone advise on the differences in moving to the double?

Single method:
-i grind into portafilter with wdt cup, a bit over the rim, wdt, remove cup and gently tap the side, then nsew with my finger, 30lb tamp in my autotamp.

for Double and 16g which is a bit underdosed in my basket I assume I must grind finer, but how much finer? On my mazzer mini would it be 1-click finer? 2, 3? Or should I just emulate exactly what I do with the single keeping my grind the same and see what happens?

Thanks to all who have given advice

[cafeIKE]

Raising the brew pressure will change the flavor profile.

It's difficult to say how you need to change the grind for a double and a single. It's coffee, basket, dose, tamp, PF, screen, spreader and brew pressure dependent.

If pulling both doubles and singles in the same session, vary the dose as changing the grinder back and forth is an exercise in frustration unless one cleans the chute, grinds a few grams and then pulls several singles or doubles to dial in the grind. IMO, it's easier to dial in the single and vary the double dose.

Of course, YMMV with different coffee, basket, tamp, PF, screen, spreader and brew pressure.