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The Six Million Dollar Expobar
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MOSFET
Senior Member
MOSFET
Joined: 31 Dec 2003
Posts: 376
Location: Long Island, NY
Expertise: I like coffee

Espresso: Linea
Grinder: Mazzer Mini
Vac Pot: Hoover
Drip: Post-nasal
Roaster: Perdue Oven-Stuffer
Posted Sat Apr 24, 2004, 6:08pm
Subject: The Six Million Dollar Expobar
 

We can rebuilt him. Stronger... faster.

I feel like I've spent that much but not quite. I'm continuing the thread "Tea and Millennium owners: tuning for the E61? here to detail my modifications for those interested.

I'm an espresso purist who very rarely tries milk drinks. I plan to in the future, but since I bought my machine about 8 months ago I've been pursuing the best espresso I can make. I've stated before, and it's still true, that I enjoy Starbucks espresso blend, specifcally when it's made through a portafilter machine. (I've also tried roasting my own and will continue to experiment with that.) So I've tried to replicate the taste at home with my Expobar. Until this weekend I almost exclusively acheived shots that had an element of bitterness. I've done everything on the to-do list to combat this. Mostly futile, until now.

But to summarize briefly my modifications, mostly to acheive temperature and pressure precision:

  1. Added a gauge
  2. Added float kit
  3. Removed water tank, pump, and flowmeter, and relocated to my basement, about 4 feet beneath the machine (this was to make it quiet)
  4. Added an electronic temperature controller (yes, PID)
  5. As per above thread, and Mark's inspiration, "de-HXed" the machine by replacing all plastic tubing with copper and wrapping six loops of the copper tubing around the boiler in the water's path prior to entering the heat exchanger. This is to preheat it in order to allow the brewing water to equal the boiler temperature. I kept the option for normal heat exchange operation by adding a second water path via valves directly to the boiler without looping. Also, I insulated the boiler and tubes leading to the group.

With all this I was able to type in a temperature in the temperature controller and measure the same temperature in the basket during brew. Also the pressure could be monitored.

So...

Why still the bitterness? Even with all this and trials of all temperature-pressure combinations, each shot was sort of ok, but "dirty", always with an aftertaste you didn't want to linger. So what changed this weekend?

I experimented by dividing the shot in two. The first half (about 0 to 12 seconds) I collected in one cup, and the second half in another. The first half tasted like crude oil and the second like Starbucks espresso from a La Marzocco. Perfect. Finally I realized that the pressure was not coming up fast enough. I was concerned about this when relocating the pump to the basement but the pressure dial speed-to-peak didn't change much from when it was in the machine.

So what did I do? Took a chance and bought a commercial procon pump and motor. And now... finally... perfection. The pressure comes up immediately and the coffee tastes clean and fantastic. And it's extremely quiet, especially since the new motor is also in my basement. See picture for exterior view of FrankenExpobar, and follow-up of happy MOSFET coffeegeek. I finally bought a digital camera. Will follow up with some interior photos.

Caveat: I may have added some water "inductance" to the pump line by making it pump farther, but even before this I could rarely escape bitterness. Vibration pumps are cheap, but in my opinion they are (at least the one in my machine) borderline sufficient for these machines and don't quite do the coffee justice.

Keith

MOSFET: IMG_0028lighter1.jpg
(Click for larger image)
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MOSFET
Senior Member
MOSFET
Joined: 31 Dec 2003
Posts: 376
Location: Long Island, NY
Expertise: I like coffee

Espresso: Linea
Grinder: Mazzer Mini
Vac Pot: Hoover
Drip: Post-nasal
Roaster: Perdue Oven-Stuffer
Posted Sat Apr 24, 2004, 6:13pm
Subject: Re: The Six Million Dollar Expobar
 

A wierdo and his friend. The wierdo is the one on the right.

MOSFET: IMG_0034tu2.jpg
(Click for larger image)
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Cryptoman
Senior Member


Joined: 24 Mar 2004
Posts: 30
Location: S. Florida
Expertise: I love coffee

Espresso: Solis SL70
Grinder: Solis Maestro Plus
Drip: Korrupts
Roaster: Air popper
Posted Sat Apr 24, 2004, 6:15pm
Subject: Re: The Six Million Dollar Expobar
 

That looks like a 1/16 DIN PID.  Cool.  Is the thermocouple in contact with the water?
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RMyers
Senior Member


Joined: 24 Feb 2004
Posts: 74
Location: Plainville, MA USA
Expertise: I love coffee

Espresso: Expobar Pulser, Solis SL-70
Grinder: NS MCF,Wega 6.2
Drip: Press Pot
Roaster: HWG
Posted Sat Apr 24, 2004, 6:21pm
Subject: Re: The Six Million Dollar Expobar
 

Wow, Keith! Please take many pictures of every aspect of this setup.

Rick
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MOSFET
Senior Member
MOSFET
Joined: 31 Dec 2003
Posts: 376
Location: Long Island, NY
Expertise: I like coffee

Espresso: Linea
Grinder: Mazzer Mini
Vac Pot: Hoover
Drip: Post-nasal
Roaster: Perdue Oven-Stuffer
Posted Sat Apr 24, 2004, 6:21pm
Subject: Re: The Six Million Dollar Expobar
 

It contacts the boiler exterior, wedged between the boiler and insulation, in an envelope of thermal grease. I wrapped foil-backed self-adhesive insulation around the boiler.

Yes, the controller is an Omega CN9000A.

Keith
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MOSFET
Senior Member
MOSFET
Joined: 31 Dec 2003
Posts: 376
Location: Long Island, NY
Expertise: I like coffee

Espresso: Linea
Grinder: Mazzer Mini
Vac Pot: Hoover
Drip: Post-nasal
Roaster: Perdue Oven-Stuffer
Posted Sat Apr 24, 2004, 6:43pm
Subject: Re: The Six Million Dollar Expobar
 

RMyers Said:

Wow, Keith! Please take many pictures of every aspect of this setup.

Posted April 24, 2004 link

One more for tonight. I'll mess around with the machine tomorrow for more photos after I've had eight or nine shots. This is a picture of the most important corner of my basement -- about four feet below the espresso machine. The procon pump and motor. Yes, I'll add sheathing or armor for the wires. It's still in test mode for this photo.

Keith

MOSFET: IMG_008875kb.jpg
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Canucklehead
Senior Member
Canucklehead
Joined: 30 Jan 2004
Posts: 52
Location: Vancouver, B.C.
Expertise: I love coffee

Espresso: Wega Lyra (h) / LM linea (w)
Grinder: Rancilio Rocky (h)
Roaster: JJ Bean
Posted Sat Apr 24, 2004, 7:22pm
Subject: Re: The Six Million Dollar Expobar
 

WOW!  That is some machine you built!

I bow before you sir!
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CaffeOle
Senior Member
CaffeOle
Joined: 28 Mar 2004
Posts: 29
Location: Bay Area
Expertise: I love coffee

Espresso: Expobar
Grinder: Mazzer Mini
Roaster: iRoast
Posted Sat Apr 24, 2004, 8:09pm
Subject: Re: The Six Million Dollar Expobar
 

This is an inspiration! And I thought I was beyond upgrade fever! Post more pictures!

It would be interesting to know which of your mods has the highest leverage on quality. For example, can you discern a difference in taste with and without the PID turned on, or do you think the pressure upgrade is more important?

Thanks!
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korngold
Senior Member
korngold
Joined: 21 Jul 2003
Posts: 636
Location: Des Moines, IA
Expertise: I love coffee

Espresso: Rancilio Audrey
Grinder: Rancilio Rocky
Drip: Melitta Clarity
Roaster: WE Popcorn Pumper
Posted Sat Apr 24, 2004, 9:10pm
Subject: Re: The Six Million Dollar Expobar
 

MOSFET Said:

I'm an espresso purist who very rarely tries milk drinks. I plan to in the future, but since I bought my machine about 8 months ago I've been pursuing the best espresso I can make. I've stated before, and it's still true, that I enjoy Starbucks espresso blend, specifcally when it's made through a portafilter machine. (I've also tried roasting my own and will continue to experiment with that.) So I've tried to replicate the taste at home with my Expobar. Until this weekend I almost exclusively acheived shots that had an element of bitterness. I've done everything on the to-do list to combat this. . . Keith

Posted April 24, 2004 link

Keith,

Those mods are amazing!  I think you may have answered your own question above, however.  All that work, and you're using Starbucks beans?  Lord knows how long ago they were roasted, and Starbucks roasts their espresso dark (almost to the point of being burnt), and what you have achieved with your amazing mods brings out the "true essence" of the beans and the roast, both age & quality.

I notice that you said you have not roasted your own--Have you tried beans from a local roaster?  You may find that that is the "perfect cup" you are seeking.  If you have more than one roaster, try a few different roasters' beans.  If you have only one, try a few different blends (espresso, Italian, "morning", etc.), and you may be surprised.  I have 2 local roasters, and 1 has an atrociously bitter espresso blend, and the other has an amazing espresso blend, but only about 50% of the time.  And, that roast goes bitter after about 5 days.  But, before that, it's beautiful (about 50% of the time)!

If you don't have a local roaster, or they are not producing a blend/roast you like, get a popcorn popper.  I have an old, yellow "Popcorn Pumper" that I bought for about $7 and a "Poppery II" that I got for $2.  The poppery burns the heck out of the beans, but the Popcorn Pumper makes a beautiful medium-dark roast in about 4:30.  Your local roaster may sell green/unroasted coffee beans, too, and they're usually cheaper than pre-blended, pre-roasted beans, and you'll never have to question the freshness.

HTH, as it seems there's not much more you could do with/to your machine!  The only "machine related' mod I can think of (not sure if you've done this) is not a mod at all--get a La Marzocco ridgeless basket, or an LM PF and a triple basket.  You'll be able to shove more grounds into either of them, which often makes for a "richer" shot.  Also, while pulling your shots, don't go by time alone--if your stream turns into "rat tails" of a light tan after about 20 seconds, cut the pump, and drink what you have.  Don't go for 25 seconds if the last 5-8 seconds are going to ruin the rest of your shot.
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marrone
Senior Member


Joined: 5 Sep 2003
Posts: 195
Location: Bakersfield
Expertise: I love coffee

Espresso: Isomac Tea
Grinder: Pasquini, Spong
Roaster: Hot Top, Fresh Roast +
Posted Sat Apr 24, 2004, 9:49pm
Subject: Re: The Six Million Dollar Expobar
 

Very very nice.

Has the insulation been effective?

Ted
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