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Extraction issues- Vibiemme Double - Page 3

Postby cafeIKE on Mon Oct 06, 2008 1:19 pm

Although puck defects are of minimal utility in diagnosing extraction problems, from what you describe, I'd say you are just a bit light on the amount of coffee and possibly need to grind finer.

See Tamping Twaddle for an exposé on the importance of tamper diameter.
A tamper tighter than 0.5mm is a PITA.
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Postby buzzmc on Mon Oct 06, 2008 1:31 pm

cafeIKE wrote:Although puck defects are of minimal utility in diagnosing extraction problems, from what you describe, I'd say you are just a bit light on the amount of coffee and possibly need to grind finer.

See Tamping Twaddle for an exposé on the importance of tamper diameter.
A tamper tighter than 0.5mm is a PITA.


Interesting read for sure. When I had a naked PF w/my Andreja Premium I don't think I ever had extractions that were that good. I almost always had 'spritzies' somewhere, and never did figure out why or how to fix that. I no longer have a naked PF, but maybe I should change that too soon.

I'll get a scale tho. That's the easiest thing to report back on and confirm/eliminate as an "issue".
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Postby miKe mcKoffee on Tue Oct 07, 2008 9:36 pm

another_jim wrote:BTW, on an E61, the pre-infusion takes around 10 seconds; so not seeing even one drop for the first ten seconds after turning on the pump is not a choke, it's normal operation.

Just to be technically correct and possibly not confuse or mislead anyone, make that E61 with vibe pump. E61 with rotary pump pre-infusion more like 3 seconds.
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Postby miKe mcKoffee on Tue Oct 07, 2008 9:42 pm

buzzmc wrote:Interesting read for sure. When I had a naked PF w/my Andreja Premium I don't think I ever had extractions that were that good. I almost always had 'spritzies' somewhere, and never did figure out why or how to fix that. I no longer have a naked PF, but maybe I should change that too soon.

Really good idea to get a nekkid PF to diag shot issues. Without one you're basically pulling blind as far as diagnosing PF build distribution issues. Work at it until spritzes are rare not the norm. Even in a fast paced environment using a modest Mazzer Major shot spritzes are rare at my cafe, all shots pulled nekkid by multiple baristas including myself.
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Postby buzzmc on Wed Oct 08, 2008 10:54 am

Lovely and descriptive as it is... What causes them? I definitely had them with the old machine... Maybe this weekend I'll cut down one of the PF's for nekkidness, and I bet I still get them often. The only thing that changed was the machine.. Same barista, grinder, tamper, and technique :)
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Postby cannonfodder on Wed Oct 08, 2008 1:12 pm

If you had channeling issues with your old setup, which is what those little jets are from, and you are having issues with your new machine but still using the original grinder and barista, then the issue is liable to be with the grinder or barista since they are the only two variables that have remained the same.

I would still start with the dose, make sure you are getting a reasonable amount of coffee in the basket. Do you have a video camera? You could record the process from the grind/dose/tamp to extraction so we could see what is happening and what you are doing. It may be something that jumps out, it may continue to be a mystery. You may want to consider getting a new set of burrs for the grinder since it came to you used. Even with worn burrs most espresso grinders will still produce a close shot unless they have been horribly abused. But as I said, I would start with a scale to verify your dose. You should be able to do 16 grams in a stock VBM double basket (Faema style basket) without a problem.

You could also try the dime test that I detailed for single shots in the Domobar Super bench review. That was for a single but it still applies to a double basket.
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Postby cafeIKE on Wed Oct 08, 2008 3:26 pm

The staler the coffee, the more it spritzzzzzzzzzzzzzz :wink:
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Postby buzzmc on Wed Oct 08, 2008 9:08 pm

18 grams for the first one after I got the scale.

Coffee's never old. Roast date on today's, oct 2, and was opened today.

Starting to wonder if my nifty grinder, purchased used off craigslist, was worthwhile.
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Postby buzzmc on Fri Oct 10, 2008 5:29 pm

So I do the same thing every time, and it would appear I get the same results every time. 18g, 4 shots in a row.

I really dislike the idea of dosing into some container, just to transfer that to the PF... Unless there's a really compelling reason to do that I'm not likely to change my ways of dispensing directly into the PF... Though, it would be easier to control the dose.

Fact is, dispensing a healing pile of ground coffee into the pf, and then leveling it off, always seems to result in 18g, and seems to never touch the screen when locked in before a shot. No tapping or other 'up-dosing' techniques are used.

As far as technique... no video camera, so that's going to be rough. But I grind more coffee than I need, I usually let to flicks of the lever drop onto a plate, and then start dispensing what I assume to be fresh ground coffee into the PF. Heaping pile is leveled with my finger, leaving a gentle concave top to the coffee in the PF.

I've tried all sorts of tamping methods... But reading a previously linked thread about tamping has got me to not worry about it all that much... Can't believe a 53mm tamp in a 58mm basket produced any sort of useful shot, let alone a shot that appeared to be better than the one that was tamped with an appropriate size tamper.

So I try and center the tamper, and one tamp, and that's it.

So far, while seemingly "new", the results appear better, but still not great. I also upped the temp last night to 221 to see how much of a difference that makes.

One thing of note is the fact that 'preinfusion' times seem to vary greatly on different machines, and thismachine with a vibe pump takes a while longer than what I'd thought before I started this topic. so I don;t even bother with thinking about the time of the shot until I see the pressure gauge start to ramp up.

Not really looking forward to a new grinder purchase... But if that's what it takes, then that's what it takes. I'm certainly not shipping this thing somewhere to get new burrs installed. Fact is it's a convenient opportunity to get something more counter frinedly like a cimballi... Especially since I never grind coffee for anything other than espresso.. Thinking strongly towards that Max Hybrid, if I decide that somehow this is indeed a grinder issue.
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Postby buzzmc on Mon Oct 13, 2008 1:55 pm

Looks like I just got a bit more lucky more than anything else with my previously better results. Things are pretty typical over time it would seem.

I still end up with pulls that are thin and light much more often than not :(
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