Espresso machines

[Mark Kelly]

Preinfusion time on an E61 is governed by the flow rate through the gicleur. If the machine was not doing this before the clean it is possible that some scale has lodged in the gicleur orifice.

I personally like long preinfusion times so I wouldn't bother changing it.

[pajotfix]

Yes - I push the lever up - wait till coffee starts to flow - than start counting again (to 25 seconds) ...

[pajotfix]

Preinfusion time on an E61 is governed by the flow rate through the gicleur. If the machine was not doing this before the clean it is possible that some scale has lodged in the gicleur orifice.

I personally like long preinfucion times so I wouldn't bother changing it.

I had to look up what a gicleur is... is this the bit that's inside the mushroom ?

[dashDustin]

interesting, all this time i thought preinfusion on an e61 just referred to some folks flipping the lever half-way, and basically just wetting the puck.

with this newly defined phenomenon, i can say that any longer than 6sec and i start doubting my grind. i typically run 17.5g, 9bar, at 198 deg. full shot time 24-27sec.

but it's all about that user-preferred flavor profile.

[pajotfix]

interesting, all this time i thought preinfusion on an e61 just referred to some folks flipping the lever half-way, and basically just wetting the puck.

with this newly defined phenomenon, i can say that any longer than 6sec and i start doubting my grind. i typically run 17.5g, 9bar, at 198 deg. full shot time 24-27sec.

but it's all about that user-preferred flavor profile.

Maybe I'm using the term pre-infusion incorrectly... It seems that the way you describe it is only possible with a plumbed machine, which mine is not... So maybe I should call it "delay" instead...

[Mark Kelly]

I had to look up what a gicleur is... is this the bit that's inside the mushroom ?

f_204.png

Yep, this bit. There are lots of opinions about what it does and how it does it but IIRC the original patent says it is for preinfusion control. On one of my E61 machines I can see the effect on the brew pressure gauge, it sits at around 400 kPa for about ten seconds then kicks up to 900 kPa. My other two machines are different: one doesn't have a brew pressure gauge and the other I have retrofitted with a DC variable speed rotary pump to give manual flow/ pressure control.

[glepore]

One of the joys of the crazy Breville DB is that they have firmware that can run the vibe pump at low pressures (ie 55% and above, at 55 the gauge never moves). It is amazing what a 20 sec preinfusion does. It takes tamp out of the equation, and now with one variable, grind is easy to find. And the shots are ridiculously consistent. Not "god shot" but I think that's palate boredom, they're probably all that good but you don't have the ones that stand out anymore because they're all good and thus you get disoriented.
The 3rd wave Slayer freaks are on to something. Profiling is a way to make a modern machine act more or less like a skilled lever operator. I've not bothered to set up profiling on the back end, but if I'm attentive to grind the long preinfusion actually makes the pressure decline in the last 20% of the shot.
Breville construction qual is iffy but very diy'able. Not nearly as cool as a Rocket on the counter, I'll admit.

[Mark Kelly]

The other side of the coin is that the traditional machines are pretty easy to find cheap second hand, pretty easy to fix and likely to outlast a new BDB.

Each of my E61 machines cost me less than half the price of a new BDB and I was able to get them running again with minimal outlay. The one caveat is the Gicar autofill controllers used in these machines which are quite unreliable and very expensive to replace. I simply designed and built my own controller boards but if you don't go that route the replacement cost might sour the deal.

[pajotfix]

So - a little update ...

Every new session with this machine showed a regular dripping from the shower screen as the boiler reached 1,2 bar... Than after a while it would stop and steam would escape. Overall other behaviour that showed something amiss with the brew valve.
So I took the group apart when I got home from work and what do you know; new mushroom O-ring ripped pretty much in two. How the hell did that happen? F*cker must have been rotten to start with... The set of gaskets I received had another size ring (the green one in the second shot) - I didn't use that as it seemed too narrow compared to the original but this is not good.

I contacted the parts shop where I got this kit. Ever seen anything like this?

[j44ke]

The schematics (PDF link) all show two gaskets there? Wondering if perhaps the green gasket goes in the slot on the end of the sleeve and the mushroom gasket is actually seated inside the group body so the threading of the sleeve into the body compresses the mushroom gasket?

Screen Shot 2020-02-14 at 2.43.20 PM.jpg

The mushroom gasket seems like something that would seal by compression rather than snugging up a gap on something being inserted into a tight fitting. Green gasket seems made of more appropriate material.

[pajotfix]

23 is a wider (white) teflon gasket that ends up under the (top) hex nut of the mushroom - larger but similar to gasket 17 in that drawing... They are not inside the group.
22 is the O-ring of the mushroom... apparently there are two sizes of these; for classic or "modern style" E61 groups... I fit the green one now but I'm having the same problems - which confirms my initial fear that it is too thin for this type of mushroom.

[j44ke]

Bah, thought I was onto something.

Edit: This place has the parts but sounds like you have a shop with them also. $2.75 or something. Bezzera 7479934.

If the same tearable material then doesn't do any good.

Also in the US so...

0128 Viton

[j44ke]

23 is a wider (white) teflon gasket that ends up under the (top) hex nut of the mushroom - larger but similar to gasket 17 in that drawing... They are not inside the group.
22 is the O-ring of the mushroom... apparently there are two sizes of these; for classic or "modern style" E61 groups... I fit the green one now but I'm having the same problems - which confirms my initial fear that it is too thin for this type of mushroom.

So what happened? I wasn't any help. Did you have eventual success?

[pajotfix]

Well, that O-ring is correct now - the green, slimmer one...
The problem remains, on and off - there is no constant drip but some remains while the boiler builds pressure as it's warming up.
Once the machine is warm and idle I once measured .17 oz of leaked water in 30 minutes.

I have replaced all rubber rings, the silicon gaskets and the valves.
I have not yet replaced the springs (they still seem springe enough) and the cam.
My focus is on the cam now; I feel that, in "neutral" steam or drips MAY come from the shower screen and when pushing it ever so slightly down (like holding my hand on the lever is enough) it will stop...
Need to take it apart but haven't got around to it yet.

While I'm grinding my coffee I let water run from the group. I'm getting great shots every time...

[j44ke]

Well as long as the shots are good!

[glepore]

So, gave up on the BDB after it needed orings yet again, have an Izzo on the way. Still going to profile though, with a flow control. Now just need to figure out how to mount both that and a temp probe without machining the group.

[Clyde]

Here's a $80 TYD Gaggia Evolution home machine. I replaced a bunch of gaskets. It pulls a shot that is hot. If one was to totally hot rod/buff out the machine it would probably benefit from a pump. There's a great company in NJ that sells the parts:

Parts and Care - Whole Latte Love

Flickr

They are $250 new and I am the original owner. I am out of the game for now so here's a project for the handy or an alternative to the high priced home machines out there.

[J_B]

Whilst wishing my local café was open on this rainy Friday, I started looking at home setups on YouTube; this result instantly caught my eye. Between the Monolith grinder and the La Marzocco, this setup costs close to nine thousand USD.

[kytyree]

I need more people like this in the world, it helps me feel more reasonable

[zetroc]

The price tag on that Monolith makes me feel super great about the money I spend on bicycles.