Modifiable espresso machine for an engineer type?

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xtronics

#1: Post by xtronics »

I get the basics - grounds are tamped - then wet the coffee(pre-infusion) before delivering hot water at a precise temperature under pressure without air.

It seems that the E61 is what I would call a brute-force method of controlling the temperature with thermal mass. The engineer in me thinks one should be able to do the same thing with a cheap PID loop ( I've written PID loop software in machine code - one can even make a hardware PID loop with a couple of transistors - this is not expensive rocket science anymore).

Most of what I read is about pump pressure - not much on rate of delivery under pressure or pressure through a standard orifice. ( Am I missing something here?)

So I want to get a machine so I can make great espresso at home - I don't need steam - would like for it to be small - can add things like PID temperature control.

I looked at the Gaggia 14101 Classic Espresso Machine - seems it is probably lacking pre-infusion.

The actual requirements should not be hard to do for $300 -$500 - the machines seem overpriced to me - but I will pay what I need to.

I hope someone can point me to something for a hands on guy to start with?
,.,.
For the record, I first had espresso in the 1970's at my cousins Italian restaurant - espresso has greatly improved over the years..

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bettysnephew

#2: Post by bettysnephew »

If you want to tinker, buy a used machine and knock yourself out. It will have a much better price to start and you may even have to fix a few things before you start to mod it. I think you will be happy with that from what I read here.
Suffering from EAS (Espresso Acquisition Syndrome)
LMWDP #586

Not2Bitter

#3: Post by Not2Bitter »

A used Olympia maximamatic might be a good start. They show up a lot for ~500 are capable of making very good espresso and could be modified fairly easily.

happycat

#4: Post by happycat »

I have a Gaggia classic and I did the following
  • Adjusted over pressure valve down
    added an Auber PID with steam control
    Swapped steam wand for Rancilio Silvia version
    Put clickable light dimmer between pump and power
PID heats machine fast
Steam wand way better than stock for milk micro foam
Dimmer gives pre infusion... Click on low power for few seconds then click off. PID reheats water in the small boiler during pre infusion. Click on and crank up to desired pressure level and adjust depending on pour quality

Fun stuff

There is a Gaggia users group out on the web. I think newer members have long taken credit for rediscovering these mods.

You can also upgrade the stock baskets... I have VST but recently got espresso HQ 14g basket that I like

This is not a great machine... Tiny boiler. But they made lots of them and you can probably find them used. You can probably do similar mods in other machines.
LMWDP #603

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aecletec

#5: Post by aecletec »

Water debit is what is usually called the flow issue. I think Slayer have a needle valve to modify this and other machines use a static restrictor - 0.6mm is a common size if I recall correctly.
Several are trialling cartridge heaters in lever groups for amateur attempts at the Bezzera Strega style system. Breville have done a similar thing in their 900/920 etc models.
Maybe there's some ideas waiting for you in those topics?

jonr

#6: Post by jonr »

The Gaggia Classic is well suited to automated flow and temperature profiling modifications. Particularly the latter, because it has a small boiler that allows you to treat it partially as a thermoblock during brew - temp rise or fall is possible (unlike most large boiler designs) without being overly sensitive (like an actual thermoblock).

Microcontrollers allow one to do much better than PID algorithms from the analog days.

https://www.coffeegeek.com/forums/espresso/m ... ods/638206

xtronics (original poster)

#7: Post by xtronics (original poster) »

Thanks for the great information.

The Gaggia classic boiler appears to be about 100ml - I'm thinking it should be enough for a double shot? (40ml/shot - 80ml) - pretty easy to do this mod:
Preheating the incoming water on a Gaggia Classic

The Olympia Maximatic boiler looks to be about 625ml
Size:

Width Depth height
Gaggia Classic 12 " x 13" x25"
Olympia maximatic 7.68" x 13.39" x 14.57"

Both have vibratory pumps.

The Olympia maximatic sounds good - not seeing any used ones for sale?? Wonder if I will find one?
I think it was sold under other names - not finding the exact models.


Might note for others on the same path - pay attention to which voltage.

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drgary
Team HB

#8: Post by drgary »

Olympia Express Maximatic = Olympia Express Coffex = Pasquini Livietta (make sure it's the old style).

As a Coffex owner who restored my machine to spec, I don't see the need for any modification. It is the perfect small footprint espresso and cappuccino machine with the wonderful build quality of Olympia Express. Also because it is so compact there are tight spaces inside. It wouldn't be so easy to modify.
Gary
LMWDP#308

What I WOULD do for a good cup of coffee!

matseski

#9: Post by matseski »

Depending on how much time you want to invest in this and if you have access to machining equipment, it might be fun to design and build one yourself. These machines are very simple.

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aecletec

#10: Post by aecletec »

As mentioned earlier, there is a whole community modding their Gaggia Classics, this one with automatic flow profiling mods etc impressed me https://www.youtube.com/watch?v=2w8TLcs5Rjg