My long and rambling path to preinfusion/pressure profiling

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#1: Post by Jake_G »

Hey all,

I'm new here but have been a creepy stalker on HB for the last several years, quietly observing and occasionally retaining some of the great pearls of wisdom that have graced this forum. My current setup consists of a mostly stock 1993 Rancilio S20 MIDI CD and a Mazzer Super Jolly with Duranium burrs. The S20 is 220V and fully plumbed in with 2 HX groups, an internal procon pump and a 5L boiler. It is definitely a dragon in terms of HX behavior. The pair hang out in my laundry room cafe and can be seen here.

I thought I would take this opportunity to introduce myself and tell the story of my love affair with espresso and the equipment that makes it. It is a tail of ignorance, hubris, years of bad espresso, a moment of enlightening, and a path to something that occasionally resembles good espresso. My history is not so unlike many others except that I ended up with a plumbed in commercial 2 group machine before I ever met miss Silvia :?. That, and life was all pixies and fairy dust until I happened upon an unreasonably good deal on a pour-over vibe-pump E61 machine that turned my world upside-down earlier this year. This story will culminate in a link to a post in the repairs section that has yet to be written, outlining the modifications I will be making to my S20. I will cross link that post back here so folks reading that thread can at least have a chance of understanding the "why?". I'll also keep an index at the bottom of this post as the story progresses.

My hope is that this multi-part story will:

-Become a conversational thread of folks reminiscing about their own journeys.

-Encourage a productive discourse regarding topics covered herein.

-Provide a perspective on the fluid dynamics between the pump and the cup that I haven't really seen communicated clearly as of yet.

-Provide a safe place for me to get my geek on without worrying about people around me slipping into a boredom-induced coma.

-Hopefully, be at least slightly amusing.

Alright, enough blabbering, I'm off to compose the first installment...
Chapter 1: From no coffee to terrible coffee
Chapter 2: Rapid upgrade-itis
Chapter 3: You bought WHAT???
Chapter 4: The fun starts
Chapter 6: The hubris sets in
Chapter 7: To have loved and lost
Chapter 8: What's going on in there, anyway? Part 1
Chapter 9: What's going on in there, anyway? Part 2
Chapter 10: Unexpected results
Chapter 11: Prior art
Chapter 12: Profile what?
Chapter 13: Option 1
Chapter 14: Option 2
Chapter 15: The build begins
Chapter 16: The calm before the storm
Chapter 17: What's going on in there, anyway? Part 3
Chapter 18: What's going on in there, anyway? Part 4
Chapter 19: There's something wrong with the machine. The water wont come out.
LMWDP #704

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Jake_G (original poster)
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#2: Post by Jake_G (original poster) »

Chapter 1: From no coffee to terrible coffee

It's mid 2008. My wife, Heidi, and I are living in Brownsville, commuting to OSU in Corvallis every day. We are not coffee drinkers. Our survival of my engineering and her biology classes consists of blending a 16 oz can of Rockstar in with a bag of frozen fruit every morning. It's healthy 'cause it's fruit.

We're renting our college home from a family friend, so we inherited quite a few appliances with the place. One day, for reasons I can't remember nor explain, we stumbled across the machine that forever changed our life. It exuded quality from every facet of being. From the delicate glass carafe (yep, I somehow broke it) to the sturdy cap that sealed in the boiling water. We found ourselves a Mr. Coffee steam powered espresso machine.

Caffé au lait, anyone? There was nothing that could keep us away from pouring pre-ground black-as-death oily beans into our new found contraption. They were fresh because they came from from those bins in the bulk section of your local warehouse grocery store (Winco, anyone?) and got freshly ground in a giant, communal Grindmaster. After making a pitcher of yummy "espresso", we'd pop in the blank portafilter disk and scald us some milk to pour into our bowl-cups. One part coffee, two parts sugar, four parts hot, bubbly milk. We knew we had reached a precipice of excellence few before us had found, because our brews tasted just like Starbucks. :|

Later (after breaking the aforementioned glass carafe) we upgraded to a Krups Il Caffé Duomo that we found for $5 while garage saleing(this doesn't seem to be a word. It should be a word). It could make drip coffee AND terrible burnt pressurised coffee sludge stuff... This worrisome chapter of our lives lasted the better part of a year. Its sad.

Not until we go visit my brother in Melbourne, Australia in March of 2010 do we receive our first meaningful lesson. On the way, my dad explains that he has a "burr" grinder in his suitcase that my brother just has to have.
"What's a burr grinder?"
"I don't know, but he has to have one."
You see, my older brother, he has a pump driven espresso machine. He explains to me the virtue of reaching the optimum pressure to release all the aromatic oils from the freshly ground beans without getting the water hot enough to burn the coffee. I'm intrigued...

We get home and pretty quickly find us a Capresso Café pump espresso machine with a Krups burr grinder for $20 for the pair on Craigslist. Score! One thing I will say for Capresso: Our unit dribbled water out of the steam wand the second you tried to steam. Being the clever chap I am, I pulled it apart and found NOTHING wrong. :( . So, I called up Capresso customer service and explained that I recently acquired one of their Café units. The friendly CSR took a couple of notes and asked me for the serial number. I looked it up and rattled it off to her...
"Sir, can you please hold?"
"Sure thing."
"Can I get your shipping address? We're going to send you a new unit. Just send the old one back in the same box, there will be a prepaid shipping label in the box."
"I mean, um. Thanks!"

Talk about standing behind their product. It wasn't a good product, but still! The Capresso Café sports a thermoblock for quick warm up, and even has a valve in the water path for purging steam pressure back into the drip tray when brewing your second cup. It has a heating element in the cup warming tray and a clever cantilevered design so it looks neat. We hung on to that guy for more than a few months while we slowly added less sugar to our morning bowls of milk and coffee. A year and a half had passed since we found that Mr. Coffee steam machine. At this point, we don't know what preinfusion is. I am pretty sure pressure profiling is a fundamental principle in aerodynamic lift and necessary for flight. And our coffee is still utterly terrible...
LMWDP #704

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#3: Post by Jake_G (original poster) »

Chapter 2: Rapid upgrade-itis

It's mid 2010, and the season is just right for falling into a vicious cycle of upgrades. The one that started it all was a CL ad for an Estro Vaporé. The seller tested it out and informed me that the portafilter was broken and that if I still wanted it I could have it for dirt cheap. I wanted it...

This machine was the precursor to the ubiquitous Starbucks Barista machines. Truly identical in every way except the badging, the portafilter design and the shower screen. The Estro models came with what Saeco calls the Grand Crema portafilter. Very simple design. Lock the filter handle into the machine and a mechanism in the handle closes a needle valve in the bottom on the portafilter. Swing the handle a bit to the left, and the valve opens. The idea was to "pre-infuse" the grounds with this valve closed. While the pressure on the top of the puck would be whatever the ulka pump could muster, so would the pressure at the bottom of the puck.

[Nerd tangent]: I didn't realize it at the time, but this is super important in fluid dynamics. It's easy to think of pressure in terms of force over area; pounds per square inch. No prob, right? The other way to look at pressure is resistance to flow . More specifically, the pressure drop in a system (difference between what the pump produces and what the puck sees) is proportional to the flow through that system (among other factors). No flow, no pressure drop. [/nerd tangent]

So, pressure on the top of the puck = pressure at the bottom of the puck with this valve closed. Great. So what? Well, my take is that this is a crude way of saturating the puck without encouraging the fines to migrate. With the needle closed on the bottom of the portafilter, there is no flow. No flow, no motion. So, the even though the puck is suspended in a solution of highly pressurized water, the coffee should be able to bloom a bit before you slide the handle over and lift the valve, letting all this highly pressurized coffee/water mixture squirt out. That said, I think the real reason the Saeco folks came up with this contraption was to allow this pressurized stuff to flash as it leaves the PF. This would qualify as a "crema enhancing" device, creating micro bubbles as the pressure rapidly decreases on the way to the cup. I eventually replaced all this stuff with a well-placed 1/4" hole in the bottom of the PF.

I used the Estro for a few solid months until yet another CL find set the stage for my current setup. A local hoarder had no less than 7 pump driven espresso machines for sale, all needing a little TLC for a bargain price. In the group were 3 Baristas (one Protèo Barista, one Starbucks, and a plastic Starbucks that had all the same guts as the metal guys) a crummy Breville Café Roma, a Francis Francis! X5, and a weird pseudo-commercial garbage machine called "Espresso Italia Easy Cup 300".

The baristas were easy fixes. Clogged check valve on the Ulka pump, weeping boiler check valve, rip the plastic guts out of the "pressurized" portafilter, etc...

The Francis Francis! was a cool machine. 57mm portafilter, brass boiler, and a P controller (no I or D in there but oh, well) for brew temp control. This guy needed a little thermal paste between the RTD and the thermal well in the boiler to be in tip top shape, with superb temperature stability. The steam button took the P controller out of the loop and used a button thermostat, which worked great. It came with two portafilters. One for Illy pods, and one for ground coffee. The ground coffee portafilter came with a special anti-sneeze tamper. The tamper piston has a shower screen on the face and pops out of the handle after tramping. You then lock the PF in the group, tamper piston and all. The water flows through the tamper piston/shower screen for extraction, and the screen keeps the grounds from going berserk when you pop the PF out of the group. Pretty clever way to keep the grounds from spraying you in the face when you don't have a 3 way valve...

I have nothing interesting to say about the Café Roma. It's a typical thermoblock disposable espresso machine.

The Easy Cup 300 was just weird. High quality components throughout but used for evil. Near as I can tell, the "Espresso Italia" brand was setup as a kind of pyramid scheme to sell these espresso capsules to small businesses. They literally GAVE the machines to folks as long as they signed a contract for capsules. You drop a capsule into the HEAVY brass portafilter, and one of the two thermoblock "boilers" would send water through the group. It had another dedicated thermoblock for steaming. I couldn't find a source for these instant espresso capsules any better than I could find a single human interested in taking it off my hands. It turned into a surprisingly heavy heap of spare parts...

As these machines parted ways with me, a few other notable machines showed up. An Estro Profi, with a built in burr grinder that I used at work for quite a while and another X5, for free. Life was good. We were enjoying coffee that had moved from terrible to just not very good at all over the course of a year or so. The Krups grinder from 2010 was doing a fine job making a mixture of coffee dust and pea gravel with the second, free Francis Francis! X5, which would remain our primary machine until the beast arrived in early 2012. Selling off all those cheap machines left me with a little budget to hunt down miss Silvia and her buddy Rocky...

Preinfusion with the X5 consisted of pump on, pump off, pull shot. Annoying. Pressure profiling was now maybe a service a consulting firm would offer to a municipality to grade their fresh water delivery infrastructure. Nearly four years in from Mr. Coffee and our cups are getting smaller and sugar isn't really needed anymore. The coffee is the best we have ever tasted. And also lousy...
LMWDP #704


#4: Post by jgordon311 »

Awesome story. I also started with the Mr. Coffee water pressure machine. And unfortunately, it also tasted like Starbucks. I had no idea what I was doing. Keep it coming.

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#5: Post by TomC »

Welcome to the forum Jake. Your story and your journey are most welcome here.
Join us and support Artisan Roasting Software=

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Jake_G (original poster)
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#6: Post by Jake_G (original poster) »

Thanks for the warm welcome!

I've got a few more chapters to cover before we get to the last 6 months, where things took a surprising turn for the better. That being said, things got pretty fun in the next chapter, even if the coffee was still mediocre, at best :).
LMWDP #704


#7: Post by mcspresso »

Do tell!! Great storytelling.

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#8: Post by Chert »

Jake_G wrote:Chapter 2: Rapid upgrade-itus
Selling off all those cheap machines...
Maybe you had your own little pyramid scheme of inspiring upgrade-itis in others?

Very entertaining coffee journey.
LMWDP #198

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#9: Post by Jake_G (original poster) »

Chapter 3: You bought WHAT???

It's late 2011. Edit! it's actually late 2012... Things are going well. I graduated, became a dad and got a full time job in June, we closed on our first house in October, and Francis and I have been getting along great. Heidi is fully aligned with taking the proceeds from our espresso machine hop-scotching (and subsequent inducing of full-blown upgrade-itis in not a small handfull of Oregonians) to hunt down a well-kept Silvia/ Rocky pair from someone who has good intentions, but lacks the patience to actually make use of the equipment.

Anyone remember using a grinder with a removable grinds hopper? This little headache alone is enough incentive for us to abandon oily roasts pretty early on. The STATIC is just maddening! The doser on the built-in grinder on the Estro is no better at containing the free-radical grounds that come from oily (and stale) beans than the stupid Krups bin. I swear, more coffee grounds end up next to the portafilter than go in. They literally leap out of the basket faster than you can dump them in. As we move to lighter roasts during this time, sugar is nowhere in sight and we settle on a set of 6oz mugs that we still use to this day.

My work has me travelling up to Portland pretty much every other week for a ten week training course spread out over 16 weeks time starting in October of 2011 (its really 2012, I'm stuck in the past...). I am in full Craigslist scouring mode, hunting for the perfect find every time I'm in town. Luckily, a few great deals just barely slip through my fingers. While hunting, I keep coming across this obscure add for a commercial machine that is much cheaper than the others out there. My curiosity is piqued, but I don't think much of it. I need a Silvia, and a Silvia I'll have.

Every time I stay in Portland, I bring my trusty side-by-side Estro Profi with me and set it up in our training building in Camas, just across and a few miles up the Columbia river from PDX. I travel on Monday morning with a few beans from home to get me through 8 hours of studying reliability strategies for industrial manufacturing equipment and then I head to downtown Portland to sample some fresh roasted offerings. Water Avenue, Stumptown, and a few others introduce me to what fresh coffee truly is. I pick up a pound on Monday after class and usually take about half that home with me on Friday. Fresh is good, even with the built-in grinder on the Estro or the Krupps at home.

The weeks turn to months and every decent deal for a Silvia is gone before I even have a chance to reach out. But every time I go to Portland, there is Silvia's older, conjoined twin brothers, mocking me. And slowly enticing me...

"2-Group Commercial Espresso Machine - $400
Got this machine from the basement of a restaurant that went out of business. Owners said it worked fine last time they used it but haven't used it in years. Front of machine says "MIDI CD Made in Italy". Blah, blah, blah."
$400? "No."
$375? "Tempting, but nope."
$350? "Hey hun, what about a commercial machine?" "Yeah, I was TOTALLY joking..."
$325? "Hmmm. Maybe she won't notice..."

I started doing some research to figure out what a MIDI CD was. Rancilio? Imagine that! I downloaded the parts manual, the owners manual and looked up all the info I could find. My searches actually led me to this forum for the first time back then, trying to wrap my brain around a machine I might be interested in. One of the members documented their rebuild and I was pretty confident I could handle whatever this machine could throw at me. It's a very compact 2 group machine. Relatively small 5L boiler, one steam tap with a matching hot water tap on the other side. Internal pump, no flow meters, only 3 solenoids, copper and brass throughout. The real deal, but compact and almost reasonable to have in a house if you squint real hard and don't think about it. I call the guy in March (January) of 2012 (yep, 2013) when I am in Portland and he has just reposted it for $300 OBO after I had assumed it was long gone...

"Hey, can I come check out the espresso machine you have for sale?"
"Sure, just meet me at my creepy storage unit in the bad part of town just after sunset. You'll know your close when the hair on your arms and the back of your neck stand straight up."
"Sounds great! I'll see you at 6. Please don't murder me."

He didn't murder me. Truth be told, when I saw how massive this thing was, and realised it was 220V, I wanted to back out. I looked it over and said "Gee, I was hoping it would be 110V. It's nice and all, but it would take a lot of effort to be able to use this at home. I couldn't give you any more than $200 for it, but thanks for your time. Also, no-one would be able to hear me scream right now nor would they likely notice or care if they did hear me. Please don't murder me." He didn't really even think about it. He just said "Ok, I'll take $200."


"Honey, I bought us a real espresso machine."

"No. It's not a Silvia."

"I know, I know. We want a Silvia. This is better. Trust me..."
LMWDP #704


#10: Post by pallen »

That thing probably has $200 worth of copper in it. What a find!