He has a small tube furnace that had a 3" ø glass tube it came with so he made a 3" pressure vessel out of stainless and put that in place of the glass tube.
Theres a welded filter plate, fixed in the center of that filter plate theres a thermocouple that extends 3/4 the length of the tube so he could get a decent temp reading during the roast.
He brought the beans up to a temp of 300f and held that for 5 minutes at 1200 psi. He said carbon dioxide not nitrogen.
Edit: he just sent me this. US3589911.pdf (156.8 KB)
1200 psi daaaaamn this dude is doing some SHIT. this paper is dope, moreso in that it’s from 1971.
carbon dioxide is an interesting choice, from the paper sounds like an easy way to displace oxygen (thanks for posting that too). i’m under the impression CO2 more reactive than N2, though i might be wrong about that. maybe it’s easier to get or easier to control pressure? (ps i don’t expect you to go back and forth with your friend to answer all my curiosities, i appreciate that you have thus far)
we in the cannabis field use closed systems and pressures in order to retain good flavor/aroma compounds and prevent imparting bad ones, I can see that applied to coffee absolutely. if I ever go back to that industry is the kind of stuff I had in mind to experiment with.
i would LOVE to taste a side-by-side comparison brew of the same bean roasted on ‘normal’ parameters vs. on his method.
CO2 it actually created inside the bean during roasting too, and is why a lot of roasters recommend not brewing beans until at least a week after roast date, before the CO2 ‘offgasses’ it inhibits flavor and fucks up the dynamics of espresso pulls. like you’ll get a pronounced, fizzy ‘bloom’ whether brewing as coffee or espresso and the flavor won’t be half as developed as a week after.
i’ve definitely wondered if that CO2 comes from a decarboxylation process
I think he probably used co2 because he was out of nitrogen or something. He does have a big ass cylinder of co2 in his shop so it was probably just what he had on hand.
From that patent it looks like you could use a couple different gasses, I’d probably choose nitrogen.
He was happy to get a call and explain it to me anyways. He’s a real old guy, he emailed me those links lol.
I absolutely love good coffee and good coffee extractions.
My budget system is a hand-crank ginder with adjustable grind size and a pourover setup using a gooseneck kettle. Monitor the water temp in the kettle so it’s heated to only 195-197degF. When you use it with freshly roasted beans you can really see the bloom reaction with the bubbling off of CO2 gas. For anyone who wants to get more serious about coffee, it’s the place to start. You really see the effects of a fresh roast, and how with longer storage time, your roasted beans become “flat” and don’t offgas as much. A good Ethiopian roast can leave you with fruity coffee that tastes like fine wine and is naturally sweet. I have had a central American bean (can’t remember where exactly) many years ago and it tasted truly like cherry wine, with the perfect amount of acidity. I’m still chasing that flavor.
For my home espresso setup I have the Breville unit with steamer ($1300-1400) and use a Rancilio grinder ($300). Breville’s seem to be the best quality for an entry level home unit for the price. I’ve had mine for a few years now and it keeps running with regular maintenance cleaning.
I have always appreciated good espresso, but never really knew the mechanics of it so I taught myself through youtube videos and lots of practice, it took a few months to really get the hang of it and the milk steaming. The number one factor for backpressure seems to be the freshness of the roast, and a fresh grind. I’m such a snob that I will sometimes throw away beans if they are too far from their roast date.
My 3-5 year plan is to actually start up or invest/partner in a new cafe where I live since it’s sort of rural and there’s not a lot of great coffee options around where I live. I used to live in Spokane and I couldn’t believe how every single coffee place, including the drive-thrus had awesome quality espresso. It’s sort of my dream exit strategy from this industry once I’ve built up enough capital that I’m happy with.
Oh also wanted to add a tip: since I’ve never formally trained as a barista, it was hard for me to get the tamping pressure consistent on my ground espresso. So I found this calibrated spring tamper device made by LuxHaus and I highly recommend it for everyone. It takes exactly 34lbs of pressure to depress the spring, and the unit itself weighs 1lb. So it’s 35lbs of pressure exactly when you press it down. A great invention for a consistent tamping pressure!
That’s been literally my only issue with making espresso (especially half awake), when I’m not thinking about it I might as well be using a jackhammer to pack the puck and sometimes will make it too tight to pass water through. Thanks! I’ll give that a look!
Steaming the milk was by far the most difficult part for me, and is now the worst part about buying a latte on the go. Pretty much no baristas know how to do it properly
Shit man, I don’t know about you but since I learned to make decent lattes I’ve probably saved hundreds if not thousands since I am a bona fide caffeine addict
The Breville Bambino has been my BFF for about 6 years now. Espresso a few times a day for me. Bought the floor model from Bed Bath and Beyond years ago for around 4 to 500, can’t recall the exact number but it’s been worth every penny.
one can’t replace good training, even for baristas it’s just as steep of a learning curve as it is to make perfect espresso. that being said it’s all about tilting your steaming pitcher just right, keeping a nice vortex going, with air being worked into the milk in as small an increment as possible. so you shouldn’t hear a schloppy, super-bubbly, sound, just a nice, constant ‘sip’ of air entering that vortex.
then, temperature. it’s lucky that the average human threshold temperature for a ‘pain’ response in the fingers is around 150-160F, and that’s exactly the temp you want the milk to end up. so if you’re using a metal pitcher for steaming, the heat conducts readily to your hand, so steam until it goes ‘ouch’. or, use a lil thermometer as a sort of training wheels, that’s common for barista training.
this technique varies for cappuccinos, vs lattes, vs. breves, etc. and different approaches are needed using skim milk vs. whole milk vs. 1/2&1/2 vs. almond milk.
cappuccinos involve working a bunch of air in right at the start, then just keeping the vortex to add those sips, to end up with a nice big foam. they should also be a ratio of 1:1:1 espresso to milk to foam, a lot of cafes add wayyyy too much milk and basically make it a latte
you are after my own heart, i love this. my pourover setup is almost exactly the same, only my grinder is electric.
totally agree freshness of roast is imperative. just as important as FF is to live res/sauce.
and yes tamping espresso evenly is just as important to packing a column for even solvent flow–perfectly analogous.
and yes dammit Ethiopian beans roasted well are friggin mind-blowing, just beautiful fruity, floral, sweet character. and the oldest coffee culture in the world.
there’s some Columbian farms that are using dry-processing and even Brix meters to analyze the sugar content in their beans, and produce amazingly fruity flavors too. Costa Rica Perla Negra roasted by One Line Coffee in Columbus, OH was a showstopper
