Coffee Appreciation

Dagnabbit, you've got me designing the damn thing now.

Key thing working against it is the big diameter (63.5mm). Pressure = Force / Area. Area is 3167 mm^2 = 0.003 m^2. 9 Bar = 900,000 Pa. Load is therefore 2850 N (285 kg) to make 9 Bar of pressure. With a 10:1 lever ratio, we can bring that down to a more manageable 28 kg. The question becomes more about whether the rubber seal can hold that pressure and if it can take 285 kg on the back of it.

So, realistically, leaning your weight on an Aeropress actually only makes between 1 and 2 Bar pressure depending how much of your weight is actually on it. I'd never really considered what it made before.

Don't know if it makes you feel any better but Paul Pratt (maker of the Cafelat Robot) says that lever machines rarely make it to (and don't require) 9 bars of pressure, most are happy in the 5-7 range.

So basically something to hold the Aeropress in place and then the lever attached to the plunger? I reckon the rubber seal would hold. Would also need to make sure that the pressure doesn't break the cup (apparently it's possible with hand plunging).

Yeah, pretty much that. I was thinking a parallel mechanism so the plunger moves roughly vertically. Aeropress slots in and I’d have the cup standing underneath, not with weight on it.

I’ve already done the CAD in Solidworks in my head.

I'll put the first order in if you're able to make a couple of prototypes :-)

Might be worth giving it a go with just the Aeropress.....then you've got the starting point. Increasing the pressure should increase the intensity/concentration as I understand it

For an initial test you could simply try standing on it which (according to your calculations) will get you to 2-3 bar depending on your weight. My guess is

a) you'll need an absolute shitload of filter papers and/or coffee in there and

b) some part of it is going to fail, either the flange bits that sit on the rim of the cup or the black filter paper holder bit (depending on how you support it), or the rubber seal.

Rubber seal failure could be quite exciting, as you may end up with a high-pressure jet of boiling liquid directed at the user's face.

Definitely in the camp of "If you want your aeropress to make espresso, get a rok/flair/robot". These sorts of things look like they'll likely smash a cup while not giving you espresso:

https://www.youtube.com/watch?v=LcqttIbH6oA

A question about coffee grinding: I'm getting to know my new Silenzio and am wondering what the difference is between a certain grind at 15gms and another, slightly coarser one at 17gms. The effort and extraction on my Robot are approximately the same. Is one preferred due to flavour or something else?
This of course applies to any grinder, but I was just wondering.

I struggled to understand this (my ignorance, but also maybe it's poorly/rarely explained) until I eventually found the following:

from https://www.home-barista.com/tips/espresso-101-how-to-adjust-dose-and-grind-setting-by-taste-t16968.html

Or to explain it another way, if you fix the flow + yield/ratio to balance bitterness/sourness, you've got a contour on the dose/grind axes to move along (as in your example, 15g/fine to 17g/coarse are both on that contour, as is presumably 16g/medium) and the position on that contour determines the "boldness" of the shot.

What I've learned from this is that all my shots are shite

Hm, thanks.

You mean the group head gasket? I followed @dubtap's lead and got the silicone Cafelat...

Just got one too. Poxy not Gaggia rubber one swelled up to the point I could hardly get the portafilter in. That resulted in pretty much a whole batch of espresso shots ruined before I realised what it was doing and I was busy blaming the coffee. Then it yielded, now the handle goes almost all the way round to the other side and doesn’t seal. Grrr.

This is quite a nice video and is related to people asking before about making espresso with cold water. However he roasts the fuck out of those beans, then adds a bunch of sweatener and milk at the end
¯\(ツ)/¯
https://www.youtube.com/watch?v=6g5z0OCWN6g

This guy is normally pretty decent and has also done a cold-pressed espresso video:

https://www.youtube.com/watch?v=kpYCwqSBdVE

Over the last week I've gathered myself this little setup. Pretty decent results with both the shots and foam today. Really excited ! Never had milk in my coffee before, but digging it!

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🐻 latte art

Question: am I ok with putting a chalk filter on both water hoses ?

Nice tray/stand thing, what is it?

It's this one
https://www.kaffemekka.dk/shop/1405-base/346-rancilio-base-til-silvia-og-rocky/

Got it for cheaps second hand

Nice!

Get in the bin. Junk.

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I'm bringing home my great uncle's great old cona coffee maker. The glass meths burner is cracked and before I buy a replacement i wondeted if anyone here recommends an alternative heating method - something with more heat control

That’s how I always remove solidified gaskets.

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