Our Valued Sponsor
OpinionsConsumer ReviewsGuides and How TosCoffeeGeek ReviewsResourcesForums
Espresso: Espresso Machines
Help!  Shots bitter with new Expobar
Barista Tools
Large selection of tampers, pitchers, milk frothers and much more!
www.espressozone.com
 
Not Logged in: Log In to Postlog in
New Topics updated topics   New Posts new posts   Unanswered Posts new unanswered  
Search Discussion Board search   Discussion Board FAQ faq   Signup sign up  
Discussions > Espresso > Machines > Help!  Shots...  
view previous topic | view next topic | view all topics
showing page 1 of 5 last page next page
Author Messages
mike01
Senior Member


Joined: 21 Jan 2004
Posts: 372
Location: SE Michigan
Expertise: I love coffee

Espresso: Izzo Alex
Grinder: Mazzer SJ, Virtuoso
Vac Pot: Yama Stovetop
Drip: Bunn HG, Clever Dripper
Roaster: Hottop
Posted Wed Sep 22, 2004, 6:15pm
Subject: Help!  Shots bitter with new Expobar
 

I just received my refurbished Expobar Pulser today from WLL.  After setting it up and letting it warm up for an hour,  I then did a 8oz cooling flush to cool down the HX and made my first shot.  I immediately noticed a bitter taste.  I thought maybe I didn't flush it long enough, so I made another and it was the same.  I tested the temperature using the styrofoam cup test with a calibrated digital thermometer.  The temp was reading 210 degrees even after a 8oz flush.  I figured the pressurestat was set too high so I tested it using this method.  "Cheap pressure gauge!"  The boiler pressure ended up being 1.2 bar.  I then lowered the pressurestat to 0.96.  However, I am still getting 207 temps even after flushing the HX.  What could be wrong?
back to top
 View Profile Link to this post
brokencup
Senior Member
brokencup
Joined: 18 Feb 2004
Posts: 1,617
Location: Atlanta
Expertise: I love coffee

Espresso: La Spaziale S1
Grinder: Cimbali Junior, Infinity
Drip: Technivorm
Roaster: RK Drum
Posted Wed Sep 22, 2004, 6:36pm
Subject: Re: Help!  Shots bitter with new Expobar
 

Brew Pressure should be between 8 and 9 bar.


Bob
back to top
 View Profile Contact via AOL Instant Messenger Link to this post
mike01
Senior Member


Joined: 21 Jan 2004
Posts: 372
Location: SE Michigan
Expertise: I love coffee

Espresso: Izzo Alex
Grinder: Mazzer SJ, Virtuoso
Vac Pot: Yama Stovetop
Drip: Bunn HG, Clever Dripper
Roaster: Hottop
Posted Wed Sep 22, 2004, 6:56pm
Subject: Re: Help!  Shots bitter with new Expobar
 

That wouldn't cause the temp to be high, would it?
back to top
 View Profile Link to this post
JonR10
Senior Member
JonR10
Joined: 26 Apr 2004
Posts: 10,376
Location: Houston, Texas
Expertise: I love coffee

Espresso: E61 Legend, Livietta,...
Grinder: Robur, B-Vario-W
Vac Pot: Hario Tabletop, Yama...
Drip: Technivorm
Roaster: 1-lb US Roaster, Behmor 1600
Posted Wed Sep 22, 2004, 7:05pm
Subject: Re: Help!  Shots bitter with new Expobar
 

mike01 Said:

The boiler pressure ended up being 1.2 bar.  I then lowered the pressurestat to 0.96.  However, I am still getting 207 temps even after flushing the HX.  What could be wrong?

Posted September 22, 2004 link

 

I knew I saw this earlier.  Took me a while to find it.  The table quoted below correlates pressure to the fluid temperature.  This is RELATED to the brewing pressure but ther are other variables (such as ambient temp, brew path length and material, etc..  Looks from your original post like you may want to try lowering the boiler pressure again (the chap below is running at 0.8 bar).  

gamgra Said:

At a boiler pressure of 1.3 Bar your boiler temp is about 125 C or 256 F , seems to me plenty hot enough.
For your information I have added a pressure / temp list based on the "steam tables"

Gaugepressure       Temp            Temp
      Bar                      C                   F
       0                     100                212
       0,1                  102                215
       0,2                  105                221
       0,3                  107                225
       0,4                  109                228
       0,5                  111                232
       0,6                  113                235                  
       0,7                  115                239
       0,8                  117                242
       0,9                  119                246
       1,0                  121                249
       1,1                  122                251
       1,2                  123                253
       1,3                  125                256
       1,4                  126                259
       1,5                  128                262
       1,6                  129                264
       1,7                  130                266
       1,8                  131                268


Perhaps you need to have your pressure gauge checked, I keep my machine, a two piston Futurmat Rimini,  at 0.8 bar. this pressure gives me a perfect brewing temperature.
Remember, no matter how high the pressure, your machine should still preheat for at least 30 minutes before use.


gamgra

Posted September 21, 2004 link


 
Jon Rosenthal
Houston, TX
back to top
 View Profile Visit website Link to this post
brokencup
Senior Member
brokencup
Joined: 18 Feb 2004
Posts: 1,617
Location: Atlanta
Expertise: I love coffee

Espresso: La Spaziale S1
Grinder: Cimbali Junior, Infinity
Drip: Technivorm
Roaster: RK Drum
Posted Wed Sep 22, 2004, 7:51pm
Subject: Re: Help!  Shots bitter with new Expobar
 

Ignore my previous post, it didn't address your issue.

Bob
back to top
 View Profile Contact via AOL Instant Messenger Link to this post
jrtATL
Senior Member
jrtATL
Joined: 20 Feb 2004
Posts: 1,035
Location: Austin TX
Expertise: I love coffee

Espresso: Expobar Office Control
Grinder: Mazzer Jolly; Cunill...
Drip: Melitta Clarity
Roaster: Drum on a Weber grill; HG/DB
Posted Wed Sep 22, 2004, 8:35pm
Subject: Re: Help!  Shots bitter with new Expobar
 

Hi.  If you are using a gauge like the one mentioned in the thread you reference, don't place too much stock in the numbers listed on the gauge.  Just because the gauge says "1.2" doesn't mean your pressure is actually 1.2.  Gauges, in my experience, can make precise measurements, but they do not always communicate the measurements accurately.

For example, the gauge I installed in my expobar reads 0.3 when the machine is completely cool and I have let out all pressure.  I know that my gauge results are skewed by 0.3.  So, if I want a setting of 1.0, I will set my machine so that my gauge reads 1.3.

All of this to say that a boiler pressure gauge is great to tell you the difference between your starting and ending point of the adjustment, it just may not tell you exactly wht the "true" pressure is.

To get you boiler where you want it, you will need to spend an hour or two playing around with it.  Jim Schulman (another_jim) has posted a great article on how to adjust your pstat without using a gauge.  I followed his advice while using a gauge, and it worked like a champ.  Basically, you flush the group, and then take a styrofoam cup reading to see what your temp is.  Then adjust your pstat a little and wait for the boiler to cycle a time or two.  Then, take another styro reading.  Keep working your way down until you get it where you want it.  

I widdled my brew temp down to 89C the other day (looking the the Italian Institute's 88C recommendation).

One final thought (especially since I have rambled on...), double check your styro cup method.  Make sure that your thermometer is not touching any part of the group while you run the test.  That would definitely skew the temp up.

Good luck, and keep us posted.

Jeremy

 
"I've appeared before every court in the state.  Often as a lawyer." - Lionel Hutz, Esq.
back to top
 View Profile Link to this post
mike01
Senior Member


Joined: 21 Jan 2004
Posts: 372
Location: SE Michigan
Expertise: I love coffee

Espresso: Izzo Alex
Grinder: Mazzer SJ, Virtuoso
Vac Pot: Yama Stovetop
Drip: Bunn HG, Clever Dripper
Roaster: Hottop
Posted Wed Sep 22, 2004, 9:04pm
Subject: Re: Help!  Shots bitter with new Expobar
 

Well, I've managed to get the temp down to 202 after flushing.  However, the steam is now pretty weak (it takes 2mins10sec to heat 10oz of 40degree water to 150 degrees) and the boiler pressure is now registering at 0.48 bars (7psi).  I'm trying to figure out possible sources of error, but I have yet to find any.  The thermometer reads 212 exactly when placed in boiling water.  I've compared the tire pressure gauge to two others I have, including a digital one, and it is within 0.5psi of the others.  I think I'll give WLL a call tomorrow and see if I can get this figured out.  Thanks for all the help.
back to top
 View Profile Link to this post
brokencup
Senior Member
brokencup
Joined: 18 Feb 2004
Posts: 1,617
Location: Atlanta
Expertise: I love coffee

Espresso: La Spaziale S1
Grinder: Cimbali Junior, Infinity
Drip: Technivorm
Roaster: RK Drum
Posted Wed Sep 22, 2004, 9:58pm
Subject: Re: Help!  Shots bitter with new Expobar
 

The implication of both your pressure and temp measurements being correct is that your heat exchanger is some how transferring more heat than the designers intended.. One possible explanation for this phenomena, is that the brew water is spending more time in the heat exchanger than it should. Another is that there is less water in the HX to heat. Have you done a water debit test to determine if your pump is providing the proper volume of water? Basically you’re looking for the pump to push 60 –100ml of water out of the group in 10 seconds. If you get less than this that is your problem..

Bob
back to top
 View Profile Contact via AOL Instant Messenger Link to this post
mike01
Senior Member


Joined: 21 Jan 2004
Posts: 372
Location: SE Michigan
Expertise: I love coffee

Espresso: Izzo Alex
Grinder: Mazzer SJ, Virtuoso
Vac Pot: Yama Stovetop
Drip: Bunn HG, Clever Dripper
Roaster: Hottop
Posted Wed Sep 22, 2004, 10:30pm
Subject: Re: Help!  Shots bitter with new Expobar
 

I did a water debit test earlier today, and it came to around 80ml.
back to top
 View Profile Link to this post
brokencup
Senior Member
brokencup
Joined: 18 Feb 2004
Posts: 1,617
Location: Atlanta
Expertise: I love coffee

Espresso: La Spaziale S1
Grinder: Cimbali Junior, Infinity
Drip: Technivorm
Roaster: RK Drum
Posted Thu Sep 23, 2004, 4:39am
Subject: Re: Help!  Shots bitter with new Expobar
 

mike01 Said:

I did a water debit test earlier today, and it came to around 80ml.

Posted September 22, 2004 link

Okay! Last theory then. There is a small hole in your heat exchanger and the venturi effect of the water flow is drawing a slight amount of very hot boiler water into the brew water stream. Far fetched, perhaps, but as Sherlock Holmes has said, "Once you eliminate the impossible, that which remains, no matter how improbable, is the solution.

If it isn't  this, we have to assume that your machine is possessed by an evil spirit and you need to call a priest. If no priest is available then Jim Schulman or Dan Kehn should do.

Bob
back to top
 View Profile Contact via AOL Instant Messenger Link to this post
showing page 1 of 5 last page next page
view previous topic | view next topic | view all topics
Discussions > Espresso > Machines > Help!  Shots...  
New Topics updated topics   New Posts new posts   Unanswered Posts new unanswered     Search Discussion Board search   Discussion Board FAQ faq   Signup sign up  
Not Logged in: Log In to Postlog in
Discussions Quick Jump:
Symbols: New Posts= New Posts since your last visit      No New Posts= No New Posts since last visit     Go to most recent post= Newest post
Forum Rules:
No profanity, illegal acts or personal attacks will be tolerated in these discussion boards.
No commercial posting of any nature will be tolerated; only private sales by private individuals, in the "Buy and Sell" forum.
No SEO style postings will be tolerated. SEO related posts will result in immediate ban from CoffeeGeek.
No cross posting allowed - do not post your topic to more than one forum, nor repost a topic to the same forum.
Who Can Read The Forum? Anyone can read posts in these discussion boards.
Who Can Post New Topics? Any registered CoffeeGeek member can post new topics.
Who Can Post Replies? Any registered CoffeeGeek member can post replies.
Can Photos be posted? Anyone can post photos in their new topics or replies.
Who can change or delete posts? Any CoffeeGeek member can edit their own posts. Only moderators can delete posts.
Probationary Period: If you are a new signup for CoffeeGeek, you cannot promote, endorse, criticise or otherwise post an unsolicited endorsement for any company, product or service in your first five postings.
Stefano's Espresso Care
Repair - Parts - Sales
Factory Authorized &
Trained Technician
www.espressocare.com
Home | Opinions | Consumer Reviews | Guides & How Tos | CoffeeGeek Reviews | Resources | Forums | Contact Us
CoffeeGeek.com, CoffeeGeek, and Coffee Geek, along with all associated content & images are copyright ©2000-2014 by Mark Prince, all rights reserved, unless otherwise indicated. Content, code, and images may not be reused without permission. Usage of this website signifies agreement with our Terms and Conditions. (0.45950293541)
Privacy Policy | Copyright Info | Terms and Conditions | CoffeeGeek Advertisers | RSS | Find us on Google+