Our Valued Sponsor
OpinionsConsumer ReviewsGuides and How TosCoffeeGeek ReviewsResourcesForums
Espresso: Espresso Machines
expobar lever
Rancilio Silvia - How to
Step by step guide for easy brewing and steaming with the Rancilio Silvia
www.seattlecoffeegear.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 > expobar lever  
view previous topic | view next topic | view all topics
showing page 1 of 2 last page next page
Author Messages
laythss
Senior Member


Joined: 19 Feb 2005
Posts: 48
Location: California
Expertise: I live coffee

Espresso: La Cimbali M23
Grinder: La Cimbali junior
Posted Tue Feb 18, 2014, 11:13pm
Subject: expobar lever
 

I am not sure if this is the right cat to post this question but I am trying to get some help to ease my learning experiance with this machine.
At idle the boiler pressure is at .8 and brewing pressure (lever closed ) is at 12. When I make a shot it takes around 13 seconds for the espresso droplets to develope at bottom of bottomless portafilter and for brewing pressure gauge to rise from 2 to around 8 ... Then there is isolation in the brewing pressure as something opens and closes (so brewing pressure goes between 8 and 7) double shot ends at closer to 30 seconds for a 2:1 ratio
When I grind a bit finer I get the bressure ranging from 8-10 after the first 13 seconds and the final shot takes around 35 -40 seconds ... No oil droplets present . Taste wise :
I suspect channelling happening somewhere which is causing the continuous pressure change , but can't see it in the puck yet The first shot tastes good but with a south taste somewhat and less crema. The second shot has a bit of bitterness and still a bit of the soury taste .
Both shots were made with fresh coffee beans from a local roaster not more than 4 days old. Grinder is a mazzer mini . Tamper is the plastic one supplied with machine which is a bit smaller (3 mm probably) than the basket.
My question :
1- what brewing pressure am I aiming for and how much difference in taste does 8 vs 10 bar make ?
2- is the most logical explanation for this variance in pressure while brewing being the distribution/tamping?
3- isn't 13 seconds a bit too long for first droplets? Isn't .8 boiler pressure a bit on the low side? Is this the cause of that particular issue?
4- I am no expert in channelling but I will take some puck photos tomorrow and perhaps someone can see what I dont.

Thanks for any comments .
P.s. the machine has a thero syphon restrictor installed by WLL
back to top
 View Profile Link to this post
SStones
Senior Member
SStones
Joined: 24 Nov 2012
Posts: 475
Location: Canada
Expertise: Professional

Espresso: Giga 5, ECM Giotto, Rocket...
Grinder: Anfim Milano-Best
Vac Pot: No  :(
Drip: Some $30 thing from Walmart
Roaster: I buy pre-roasted.
Posted Wed Feb 19, 2014, 6:25am
Subject: Re: expobar lever
 

I am NOT very familiar with the expobar lever, but do know heat-exchanger machines fairly well. Boiler pressure idling at 0.8 seems low to me. If your boiler pressure is too low, you'll always be brewing at a lower than optimal temp.
It seems to me that that may be a 2-boiler machine in which case the steam-boiler pressure isn't going to affect the brew much. But if it's a heat-exchanger machine, then you may just want to raise your pressure slightly.

Before you start brewing, do you do a cooling flush?  Is the initial flow from the cooling flush so hot that it actually boils on the face of the shower screen as it escapes?  How many seconds of this boiling do you get before it steadies into all-liquid water?
On my older Giotto, I keep the boiler pressure high (1.25-1.3) for the steam.  On my Rocket Giotto, it hovers around 1.0-1.15 bar boiler pressure. It was lower than that when I first received the machine around 0.8-1.0 and I found the shots to be a little sour. What I noticed most was that the machine barely gave any boiling water when I tried to give it its cooling flush.
Your times will be different than mine, but at 1.0-1.15 bar, the cooling flush is less than 4 seconds and the steamer is still very capable.
back to top
 View Profile Link to this post
boar_d_laze
Senior Member


Joined: 21 Nov 2006
Posts: 1,203
Location: Monrovia, CA
Expertise: I live coffee

Espresso: La Cimbali M21 DT/1 Junior...
Grinder: Ceado E92; "Bunnzilla"
Vac Pot: Royal Coffee Maker
Drip: Chemex + Kone; Espro Press
Roaster: USRC Sample Roaster
Posted Wed Feb 19, 2014, 8:34am
Subject: Re: expobar lever
 

Any time I hear about consistent "in the cup' problems and there's a La Cimbali grinder in the mix, I suggest removing the hopper to check for a bad bean trapped on the deck or in the collar, vacuuming the deck, cleaning the fragments out the collar with some sort of sharp pick, cleaning the grinder with Grindz or instant rice, and re-seasoning it.  Even if the grinder wasn't the problem, cleaning it didn't hurt.  

Normal boiler pressure for one machine is too low or too high for others.  WLL's website says 1.0 to 1.5 is normal for the Expobar Lever; but I don't know if your low reading is caused by an inaccurate gauge, or whatever.  

What I do know is that if you've got good steam, your boiler is hot enough to heat the water in the heat exchanger to brew temperature.  And, if you get reasonable temperature recovery times between shots -- say no more than two minutes after drawing a shot before you can draw another -- but not so fast that you need a fresh cooling shot after the same two minutes of idling, your boiler pressure is fine.

If you don't have good steam, and/or you've got a long recovery time for brew temp and/or steam, then you'll need to adjust the p-stat to raise the boiler pressure/temp.  PV = nRT and all that.

If we have to get deeply into your machine's state of health, we'll also need to know how much pump pressure it produces against your back-flush disk.

At idle the boiler pressure is at .8 and brewing pressure (lever closed ) is at 12. When I make a shot it takes around 13 seconds for the espresso droplets to develop at bottom of bottomless portafilter and for brewing pressure gauge to rise from 2 to around 8 ... Then there is isolation in the brewing pressure as something opens and closes (so brewing pressure goes between 8 and 7) double shot ends at closer to 30 seconds for a 2:1 ratio
When I grind a bit finer I get the pressure ranging from 8-10 after the first 13 seconds and the final shot takes around 35 -40 seconds ... No oil droplets present.

Taste wise: I suspect channeling happening somewhere which is causing the continuous pressure change , but can't see it in the puck yet The first shot tastes good but with a south taste somewhat and less crema. The second shot has a bit of bitterness and still a bit of the soury taste.

Assuming your 2:1 is an expression of the weight of the shot compared to the weight of the dose; and assuming that the dose is between 14g and 20g:
13sec is on the slow slide, for the first visible signs of moisture; but not slow enough to panic.

12bar on the brew pressure gauge with the pump off has to be a false reading of some sort.  I don't know if it's significant though.  Let's hope there's someone with a lot of Expobar experience who can tell us for sure.  But since the shot otherwise develops normally, it doesn't seem to be a problem.

A pressure ramp up over time is normal with any vibratory pump, and E-61 heads increase the ramp time because the first part of the pull is pre-infusion.  Vibratory pump pressures depend on the load in the circuit, the more load the more pressure.  

An 8bar max is a little low.  You really want 9bar or just a skosh higher as the max.  But the flow rate is actually a better evidence of what's going on than the gauge.  

Thirty seconds for a normale (2:1, aka 50% brew ratio) is an appropriate flow rate, so I'm not terribly worried by the pump reading.  FWIW, you still get a "within the standard range" flow rate, if you  calculate "dwell time" at 1/2 pour time, per Jim Schulman.    

A finer grind creates more resistance in the circuit, so you'd expect a higher pump reading.    

With a naked pf, channeling is not be a matter of observation, not speculation.  The pressure variation you see in the gauge could be the gauge itself, or the pump.  It is not the OPV because you get higher pressures when you grind finer.  

"Oil droplets" at the beginning phase of a naked pf shot, is a good thing.  But there's some information you're not providing.  How long does it take the extraction to go from droplets to cone?  When the cone forms, is it centered?  Does it hold steady in place, or does it move around?

Lack of droplets in your finer ground shots just means that the puck isn't fully wetted during the pre-infusion period, and that the first sign of moisture comes after the pump is putting out heap much pressure.  Not terribly informative because expected.  

If "sour" isn't the coffee itself, it's a sign of under-extraction; most often low brew temperature, and/or too fine a grind, and/or too large a dose.  If it's temperature, brew hotter.  For instance, even though you're getting good flow rate you may need to adjust your grind/dose to a smaller dose and/or coarser grind.  Getting grind/dose right can mean a lot of tweaking.  

That said, most baskets have a fairly narrow range for "best dose," and if you can establish what that is for yours, you've at least eliminated one variable.  Another piece of good news is that the La Cimbali Jr., makes adjusting grind as precise and convenient as possible.  Few grinders are as good in that respect, and none better.

In the special language of coffee, a shot can't be simultaneously "bitter and sour."  It's one or the other, or "balanced."  Since your first shot is more sour than your second, I tend to (a) suspect that temperature is the variable; specifically (b) that the brew temp of the second shot is hotter than the first.  However, other possibilities include that the coffee itself may have an inherent sourness; and/or your use of sour and bitter as terms of art is non-standard.

One of the first things you have to do, if you haven't already, is educate your palate to the terminology.  Try brewing a shot with no cooling flush at all after a long idle, so the water is very hot.  That should make it very bitter.  Then try brewing the second shot immediately after a very long cooling flush -- say 15sec after flash boiling ends -- that should make it very sour.    

After you've established that you can brew too bitter and too sour by changing the temp, you have to "dial in" the temp for the coffee (and do it every time you change coffees).  Use counting the time for a cooling flush from the reference point of flash boiling; and bracket between too hot and too cold with jumps in temperature that are big enough so that you can tell the difference.  Once you're not sure whether either side of the bracket is too hot (bitter) or too cold (sour) split the difference, say "wotthehell wotthehell," and call it a day.  

There's no way to know for sure without testing each coffee, but something like 85% have sweet spots within the 198.5F to 200.5F range.  With a little experience you'll find the right count for that.  That will become your starting point, and you'll be able to "dial in" with no more than two or three shots.    

If your machine's okay (and your grinder isn't fouled), you'll be able to balance bitters and sours by tweaking temp, grind and dose.  But it takes a lot of practice.  

Hope this helps,
Rich
back to top
 View Profile Visit website Link to this post
steamer
Senior Member
steamer
Joined: 11 Feb 2005
Posts: 900
Location: socal
Expertise: I live coffee

Espresso: Expobar Brewtus IV R
Grinder: Mazzer Mini-B Baratza...
Vac Pot: Krubs Moka Brew, vacPot
Drip: TechV, and many more
Roaster: Hottop
Posted Wed Feb 19, 2014, 9:15am
Subject: Re: expobar lever
 

I have the same machine, I have had it a few weeks, it does come set at .8/.85, and 12 bar. I adjusted mine to 1.0 Bar and it cycles from .9 to1.0 every minute. I find that too fast of an cycle to maintain. I am current working with WLL on this now. The naked portafilter that came with my Lever is very consistant to squirting all over the place. On my Vairo-w, I'm at 1 and F on the settings. I'm using fresh beans, but they are lighter roasted than the normal dark espresso beans. I'm using 20gr in a triple basket in the NPF. I got my tamper pressed way heavy on the dose. I get drops at close to 7-10 seconds, then finishes at about 25 seconds for 2oz shot. I'm learning this machine from coming from a Gaggai Classic.
back to top
 View Profile Link to this post
laythss
Senior Member


Joined: 19 Feb 2005
Posts: 48
Location: California
Expertise: I live coffee

Espresso: La Cimbali M23
Grinder: La Cimbali junior
Posted Wed Feb 19, 2014, 8:33pm
Subject: Re: expobar lever
 

Thanks steamer and d_laze,
Steamer my upper gauge which is the boiler pressure shows 7.5/8 where do I adjust that to make it higher on the machine? Do u have a picture?
D_laze not sure I can get to answer all the questions u asked , but I will try :
1- grinder I am using is a mini mazzer actually and it is brand new.
2- WLL told me that the top gauge is boiler pressure and that it only effects the steam power !! And the lady said .8 is fine !
3- blind filter in brew pressure settles at 10 bar after 30 seconds or so .
4- takes another 5 seconds I think for cone to appear so total 18 seconds from opening valve (I will measure and check for sure)
5- channelling is sometimes happening and evident at start and such shots I am not using for refrence here.
6-

If "sour" isn't the coffee itself, it's a sign of under-extraction; most often low brew temperature, and/or too fine a grind, and/or too large a dose

I thought too fine of a grind causes over extraction and sour taste ?
7- and I think this makes the idea of water temp being the most viable answer . I did what u said to get my terminology straightened and waited 4 hours before I made a shot , then made a shot of espresso with out flushing. It tasted almost perfect and came out nicely in about 30 seconds ( abit of channelling and probably needed to be finer but that is a different issue).
Then I ran 12 oz of water out of machine and used same grinder setting and made a shot right after (less than 2 sec recovery) and it was a sour shot , closer to what I usually get out of the machine .
back to top
 View Profile Link to this post
GVDub
Senior Member


Joined: 25 Jan 2008
Posts: 849
Location: Los Angeles, CA
Expertise: I live coffee

Espresso: Londinium I, Arrarex...
Grinder: Gaggia MD85, Dienes Mokka,...
Drip: Behmor Brazen, Abid Clever
Roaster: Behmor 1600
Posted Thu Feb 20, 2014, 8:20am
Subject: Re: expobar lever
 

laythss Said:

6- I thought too fine of a grind causes over extraction and sour taste ?
7- and I think this makes the idea of water temp being the most viable answer . I did what u said to get my terminology straightened and waited 4 hours before I made a shot , then made a shot of espresso with out flushing. It tasted almost perfect and came out nicely in about 30 seconds ( abit of channelling and probably needed to be finer but that is a different issue).

Posted February 19, 2014 link

Over extracted is bitter, under extracted is sour. Also bitter is generally tasted on the tip of the tongue, sour on the sides. Just knowing that has helped me isolate problems in the past.
back to top
 View Profile Link to this post
Bogiesan
Senior Member


Joined: 1 Jan 2002
Posts: 43
Location: boise Idaho, usa
Expertise: I live coffee

Espresso: Salvatore Famosa c.2000
Grinder: Rancilio M40
Posted Thu Feb 20, 2014, 9:16am
Subject: Re: expobar lever
 

GVDub Said:

Over extracted is bitter, under extracted is sour. Also bitter is generally tasted on the tip of the tongue, sour on the sides. Just knowing that has helped me isolate problems in the past.

Posted February 20, 2014 link

This misperception is known as the myth of the tongue map, a misunderstood and misquoted bit of research done early in the 20th Century. The tongue's taste receptors are evenly distributed. This wiki includes links to the research that repeatedly attempts to debunk the old map..

http://en.wikipedia.org/wiki/Tongue_map

 
I play go. I use Macintosh,. Of course I ride a recumbent.
back to top
 View Profile Link to this post
steamer
Senior Member
steamer
Joined: 11 Feb 2005
Posts: 900
Location: socal
Expertise: I live coffee

Espresso: Expobar Brewtus IV R
Grinder: Mazzer Mini-B Baratza...
Vac Pot: Krubs Moka Brew, vacPot
Drip: TechV, and many more
Roaster: Hottop
Posted Thu Feb 20, 2014, 9:22am
Subject: Re: expobar lever
 

laythss Said:

Thanks steamer and d_laze,
Steamer my upper gauge which is the boiler pressure shows 7.5/8 where do I adjust that to make it higher on the machine? Do u have a picture?
.

Posted February 19, 2014 link

Make sure the machine is cold before getting inside.
1) Remove the 5 Phillips screws holding the back and sides on (2 on each side, one in the back towards the bottom).  The back and sides are a continuous U-shaped piece.  The piece is very heavy.  Take caution not to drop this piece.  
2)  Depending on the location of the pressure stat, sometimes the inner stainless steel piece does not need to be removed.  Follow step 3 if you can not locate your pressure stat.  The pressure stat is between the boiler and the panel.
3)  The inner stainless steel piece covers the top and includes the place where the water tank rests.  Remove the two 3mm Allen screws from the left side (near bottom, on the same side as the reservoir).  You will also need to remove the two screws on the top of the machine, near the front.  These can be either Phillips or Allen screws. (Not all machines have screws on the top)
4) Locate the pressurestat. It is a black, plastic device with electrical connections in the top and a copper pipe with a brass nut at the bottom.
5) Looking downward at the pressurestat, you can see an adjustment wheel (a gear or toothy wheel).  Adjust 1/4 turn counter-clockwise to lower pressure, or clockwise to increase pressure.
6) You should now reassemble the machine and allow it to heat up.  If more adjustment is needed, allow the machine to cool and repeat steps 1-5.
7) Once 1.2-1.4bars has been reached (or your safety relief valve stops releasing steam) your pressure has been adjusted to the proper level.

I have mine set at 1.1 right now.
back to top
 View Profile Link to this post
GVDub
Senior Member


Joined: 25 Jan 2008
Posts: 849
Location: Los Angeles, CA
Expertise: I live coffee

Espresso: Londinium I, Arrarex...
Grinder: Gaggia MD85, Dienes Mokka,...
Drip: Behmor Brazen, Abid Clever
Roaster: Behmor 1600
Posted Thu Feb 20, 2014, 9:26am
Subject: Re: expobar lever
 

Bogiesan Said:

This misperception is known as the myth of the tongue map, a misunderstood and misquoted bit of research done early in the 20th Century. The tongue's taste receptors are evenly distributed. This wiki includes links to the research that repeatedly attempts to debunk the old map..

http://en.wikipedia.org/wiki/Tongue_map

Posted February 20, 2014 link

Well, I taste bitter on the tip on my tongue and sour on the sides, predominantly, so the debunkers can go take a leap, at least as far as my tastebuds are concerned. Besides, they're not so much debunking as refining. The article you link to plainly states that "while some parts of the tongue may be able to detect a taste before the others do, all parts are equally good at conveying the qualia of all tastes," leaving the conclusion that threshold tastes do have specific areas and can detect certain flavors faster, while the entire tongue does have an overall mix of sensors. And threshold is a big clue.
back to top
 View Profile Link to this post
GVDub
Senior Member


Joined: 25 Jan 2008
Posts: 849
Location: Los Angeles, CA
Expertise: I live coffee

Espresso: Londinium I, Arrarex...
Grinder: Gaggia MD85, Dienes Mokka,...
Drip: Behmor Brazen, Abid Clever
Roaster: Behmor 1600
Posted Thu Feb 20, 2014, 9:33am
Subject: Re: expobar lever
 

duplicate, mods please remove.
back to top
 View Profile Link to this post
showing page 1 of 2 last page next page
view previous topic | view next topic | view all topics
Discussions > Espresso > Machines > expobar lever  
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.
Commercial Equipment
Nuova Simonelli, La Marzocco, Rancilio. Nationwide installation. Instant financing options.
www.seattlecoffeegear.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. (0.400021791458)
Privacy Policy | Copyright Info | Terms and Conditions | CoffeeGeek Advertisers | RSS | Find us on Google+