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Topic: Sour expresso taste (5 msgs / 161 lines)
1) From: Mike Wilkens
Bryan, Denis: thanks, I'll try to provide some more info.  I haven't weighed most of the shots, but in one case the ratio of coffee to liquid was 47% (14 g coffee resulting in 30 g liquid in 26 seconds), probably lower in earlier cases.  I try to judge the flow color best I can and stop when I see watery flow.  I try to adjust the grind and dose to make that brew time come out to 25-30 seconds.
Beans are Counter Culture Coffee's Toscano, 17 days now since roasting, stored in valve bags and airtight glass jars, once opened.
Flow is not going from black to blonde instantaneously, and I think flow transition is better at present, I see dark brown flow, leading to brown flow leading to yellow, to watery.  It's thin and there's very little crema at finer grinds, when I grind coarser I get maybe 30% crema.  Flow was really too fast on that pull though.  Crema color is usually OK now (before, it was yellow), not dark brown but not tan, medium brown I suppose.
I've been told that lack of crema is a sign the extraction's wrong.  If that's true, I don't know how to fix it except grinding coarser.
At this point some shots taste sour, some shots taste bitter or metallic, and as cappuccinos, some taste sour, and some taste OK, and some taste bland.  At least I'm able to modulate the taste somewhat.  But I'm not able to control it.
-Mike
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2) From: Bryan, Compass Coffee
IMO your beans are past their prime, even under proper storage conditions.
You should also be grinding finer at this point, not coarser.  Try a smal=
ler yield, 30g is quite a bit of yield for a 14g dose.  If you don't have=
 a small .1g scale that you can set your cup on while you are pulling your =
shot into it you need to get one.  I think it will help your situation a =
ton.
If, at any point, your crema goes to "watery" you should have stopped your =
shot about 10 seconds prior.  Seriously.  It's not to be harsh or hurtf=
ul, but that's waaaaay beyond anything you should be seeing.  That's like=
 roasting until second crack slows.  At the first sign of "yellow" you sh=
ould be killing the pump.
To me it doesn't sound like anything is wrong with your equipment, it sound=
s like you just need to adjust some shot parameters.
-bry
 From: Mike Wilkens 
To: homeroast =
Sent: Saturday, June 9, 2012 11:21 PM
Subject: Re: [Homeroast] Sour expresso taste
 =
Bryan, Denis: thanks, I'll try to provide some more info.  I haven't weig=
hed most of the shots, but in one case the ratio of coffee to liquid was 47=
% (14 g coffee resulting in 30 g liquid in 26 seconds), probably lower in e=
arlier cases.  I try to judge the flow color best I can and stop when I s=
ee watery flow.  I try to adjust the grind and dose to make that brew tim=
e come out to 25-30 seconds.
Beans are Counter Culture Coffee's Toscano, 17 days now since roasting, sto=
red in valve bags and airtight glass jars, once opened.
Flow is not going from black to blonde instantaneously, and I think flow tr=
ansition is better at present, I see dark brown flow, leading to brown flow=
 leading to yellow, to watery.  It's thin and there's very little crema a=
t finer grinds, when I grind coarser I get maybe 30% crema.  Flow was rea=
lly too fast on that pull though.  Crema color is usually OK now (before,=
 it was yellow), not dark brown but not tan, medium brown I suppose.
I've been told that lack of crema is a sign the extraction's wrong.  If t=
hat's true, I don't know how to fix it except grinding coarser.
At this point some shots taste sour, some shots taste bitter or metallic, a=
nd as cappuccinos, some taste sour, and some taste OK, and some taste bland=
.  At least I'm able to modulate the taste somewhat.  But I'm not able =
to control it.
-Mike
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3) From: Scott Miller
I'll second the beans being past their prime as a possible suspect.
When I dialed in my Gaggia Coffee DeLuxe, years ago, I went to the point of
getting the grind too tight, then backing off of that to reach the best
point... now, I've always preferred going in the direction of too fine,
then backing off the grind.
Not sure if that's a smart way to do it, but it worked for me.
cheers,
Scott
On Tue, Jun 12, 2012 at 10:29 PM, Bryan, Compass Coffee <
bryan> wrote:
<Snip>
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4) From: Michael
The comments below seem fine except for one quibble.
<Snip>
I aim for that ratio (around 50%) with my regular shots. That's about an ounce of liquid although perhaps more volume when you have a good head of crema. Any higher ratio (less weight of espresso output to weight of grinds) would be heading away from a normale towards a ristretto. Let's save that for the advanced class :-).
On Jun 12, 2012, at 10:29 PM, Bryan, Compass Coffee wrote:
<Snip>
michaelb
espressoperson
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5) From: John Stewart
I have one comment and one question.
I have a PIDed Silvia - so my environment is different - but, I was surpris=
ed how high I had to set my PID to get the right temperature to the portafi=
lter.  To discover the correct temperature setting, I used the styrofoam =
cup method.  The method in short is cut a styrofoam cup so it fits roughl=
y where the portafilter does.  Poke a hole in the cup with your thermomet=
er and carefully hold it in place while you collect a couple of ounces of w=
ater via the extraction cycle.  Be careful  -  don't burn yourself.=
  I found that a PID setting of about 232 gets me 2 ounces of 200 degree =
water in the cup.  I used 30 minutes of warm-up with the portafilter in p=
lace before running my test.  I did a little experimenting without runnin=
g any water through the group head, and running 2 ounces 2 minutes before t=
he test or 5 minutes before the test and didn't find any difference. 
Now for the question.  At what point does pressure come into the discussi=
on?  Is it not in the discussion so far because the machine in question d=
oesn't have easy pressure controls?  Or in other words, will a case of co=
arser grind and lower pressure produce a more sour shot versus a case of fi=
ner grind and higher pressure - each producing the same volume of shot in t=
he same time?
John
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