Posted Sun Dec 9, 2012, 5:09am Subject: Re: Extraction looks great, glupy red-brown, but goes pale and watery after
Is that your extracted puck shown in the video? I am not too familiar with the machine but the puck(grind) look rather dry and fine? Have you tried grinding coarser and see how it changes from there? You could break the coffee puck to see if any part of the puck is dry after extraction to indicate significant channeling.
kingoslo Senior Member Joined: 24 Dec 2011 Posts: 33 Location: OSLO Expertise: I like coffee
Posted Sun Dec 9, 2012, 8:21am Subject: Re: Extraction looks great, glupy red-brown,
Hello guys,
I have tried the things which were suggested. These are my observations:
North - south - east - west tamp: I take it, that this consists of four vertical tamps, one in each corner of the basket, pressing straight downward direction. I did this. First extraction I did, it seemed to run blond after 10 seconds too, but perhaps in a more progressive way, the turning from red-brown to blond happened in perhaps 2 seconds rather than in one.
Because this didnt solve the problem, I tried to dose less. I normally dose 14-15 g in the basket. I tried dosing 15g, 14g, 13g. The less I dosed, the quicker it ran pale.
When I dissect the puck, I found that the outside of the puck is darker than the inside. It looks moist around the edges and top. The center looks dry. I often notice little pinholes in my puck. Sometimes in the center, but often around the outside edges.
Posted Sun Dec 9, 2012, 9:48am Subject: Re: Extraction looks great, glupy red-brown,
kingoslo Said:
When I dissect the puck, I found that the outside of the puck is darker than the inside. It looks moist around the edges and top. The center looks dry. I often notice little pinholes in my puck. Sometimes in the center, but often around the outside edges.
For the reduced dose, grind a bit finer as well. You can also try increacing the dose, this can slow the pace But for major increaced dose, it may be necessary to coarsen the grind. (Grind setting and dose work together)
Tamp once, straight down, simple and efficient.
For edge channeling (more exposure around the edge than in the middle) you might try nutating for distribution prior to the tamp. Here is a conversation about nutation CLICK HERE
You also might try John Weiss' WDT (this is what I do). CLICK HERE
Coffeenoobie Senior Member Joined: 11 Dec 2011 Posts: 2,320 Location: PNW Expertise: I like coffee
Espresso: N S Oscar Grinder: Vario W
Posted Sun Dec 9, 2012, 11:44am Subject: Re: Extraction looks great, glupy red-brown,
Your puck dissection seems to support my theory about side channeling. I wish I could hit my puck once but if I don't do the NSEW I get channeling. And I never, ever even without the 4 side tamping get the stack of grinds on the walls that you get. I get stray grinds but nothing like what you have. I think your tamper could be a tad larger.
Coffeenoobie
Buying advice: GRINDER GRINDER GRINDER. Don't cheap out on the grinder. My coffee treasure map... Click Here (maps.google.com)
kingoslo Senior Member Joined: 24 Dec 2011 Posts: 33 Location: OSLO Expertise: I like coffee
Posted Sun Dec 9, 2012, 5:01pm Subject: Re: Extraction looks great, glupy red-bro
Ok, thanks! I will try everything which has been presented to me in the morning.
Until then, when I bought the machine I lowered the brew pressure to 9.5 bar. Do you think this could be causing the problem? I think stock pressure was close to 10.5 bar.
Posted Sun Dec 9, 2012, 5:53pm Subject: Re: Extraction looks great, glupy red-bro
I am not sure if what I think is possible, but may be your grind is too fine that the water can't go through the center of the puck at all? And because it's overly fine, instead of choking, the water find the least resistance to be around the edge, thus the sudden blonding. It's as if only 30% of your dose coffee can be extracted(around the outer surface of your puck), the 70% in the middle are inaccessible and thus never extracted. So, if it's not too much hassle, try coarsen the grind a wee bit and observe the changes.
Your distribution seems fine to me, and it could even be overly meticulous. So I don't understand why the major side channeling other than what I said above. Try using WDT instead because it's much easier and gives comparable result to sifting. Easier and same result, why not?
The pressure could potentially be a factor, but it shouldn't be that significant considering a lot of people out there is extracting with 10.5 bar on Gaggia Classic and none reported this problem.
The guy above has the same machine as me, but I have Compak K3 not a Vario. I tried to replicate his method, which perhaps seemed to work a bit better than my method. The extraction didnt go blond until aprox 18 second!! I tried a few more times, but I could not replicate the situation. The next few times all failed, and went blond after about 10 sec. After wasting too much coffee, i tried the other things which were suggested to me.
Various grinds, from really coarse (the water would flow through the puck, but it would flush straight through and I could not build up pressure. I went gradually finer, until I ended up at the grind setting I use most of the time. As I went to finer grind I started getting channeling.
Third I tried dosing in a covex shape, so that when I tamped, the edges would have more compact puck, while the center would be compacted less. My hypothesis was that I was hoping the coffee would be more inclined to seep through the center. This was not the case, although the coffee arond the walls were denser, I got massive channeling around the edges, and when looking at the puck, the sides were running wet, but the center was rock hard.
I tried WDT a few times during the session. I thought this seemed to result in a worse extraction than both finger-NSEW distribution and sifting.
What are your thoughts? How can I aid your troubleshooting of my method? I will be happy to post photographs or video of anything which could help resolve my situation.
A have bought a naked portafilter, but it is going to take some time to arrive.
WDT seemed to make the problem worse today and yesterday. I notice that the funnel is by the wall of the basket, which is where the hypothetical channeling happens . Perhaps there is a link? I use a long steel sowing needle to stir.
I have been grinding lots of different beans over the last few days. Some are a week old, the oldest ones were about 2 weeks old.
How I weigh depends on how I distribute. The best brews I've gotten has been when I have just eyeballed the level. But when I want to be accurate, I weigh the basket and beans, and subtract the weight of the basket. Sometimes I weigh the grind. Depends on how I distribute. My scale has 0.1 grams resolution and 0.1% absolute accuracy.
I think the sides are getting a good tamp by using NSEW tamp. But I buy one which is 58.4mm if there is a consensus this is causing the problem. I do tamp the sides well after you made me aware of this.
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