La Peppina Termomatica - Page 2

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truemagellen

#11: Post by truemagellen »

So this is an old video I used to learn.
This guy does an extra pump for more volume after shot starts and adds pressure by lifting lever. You can do these things but if your spring is good it's not really necessary.

I've owned a micro cimbali and faema faemina and peppinas oncen dialed in will be a bit easier to have consistent shots and shot quality it can match it.

You will have wet pucks with this machine since it is basically a piston pump with no 3 way valve.

LObin

#12: Post by LObin »

Sounds like your piston may be slipping. What lubricant did you use?

With some lever manipulation, you can easily pull 1:2.5 ratio.

I'm posting this for motivational purposes only. :wink:
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yakster
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#13: Post by yakster »

truemagellen wrote:So this is an old video I used to learn.

video

This guy does an extra pump for more volume after shot starts and adds pressure by lifting lever. You can do these things but if your spring is good it's not really necessary.

I've owned a micro cimbali and faema faemina and peppinas oncen dialed in will be a bit easier to have consistent shots and shot quality it can match it.

You will have wet pucks with this machine since it is basically a piston pump with no 3 way valve.
That old video is still around. I started out with the PID but found that if the kettle was at least half full it was pretty stable so I ditched it. With the Termomatica it should be even less of an issue. I didn't even have a good grinder yet when I made that video.

So you basically want to load the group with water which I do with partial pumps until I feel resistance. For a double, around 14 g IIRC, I'd wait about 10 seconds after loading the group and feeling resistance and then push the lever down again to start the pull. With the single basket I didn't wait any time otherwise it tasted overextracted.

Good luck, these are lots of fun. As long as you can pump water into the group and have the flapper valve shut and hold pressure against the puck you should be OK. I played with fine tuning the flapper valve under the dispersion block. With the screw too tight, the valve would be cupped so I left it a bit loose. I was pulling shots with the block off and adjusting the screw tension for the best spray, but I don't think it's that critical.

With a good grinder and spring there's generally no need to help the lever up. I haven't done that in quite a while.
-Chris

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XS750AU (original poster)
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#14: Post by XS750AU (original poster) »

LObin wrote:Sounds like your piston may be slipping. What lubricant did you use?

With some lever manipulation, you can easily pull 1:2.5 ratio.
Can you explain piston slipping? Does it slip on the down stroke and allow air into the cylinder or does it slip on the way up and allow water to blow past?

I am not seeing any leakage of water. I am suspecting that the flapper valve is leaking. I will post s video tonight, that may help with the diagnosis.

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truemagellen

#15: Post by truemagellen »

yakster wrote:That old video is still around. I started out with the PID but found that if the kettle was at least half full it was pretty stable so I ditched it.
.
Funny thing is, when I learned the peppina from this video I knew it was you...but then time went on and I forgot , but I saved it a long time ago :mrgreen: :mrgreen:

Thanks again :lol:

LObin

#16: Post by LObin »

XS750AU wrote:Can you explain piston slipping? Does it slip on the down stroke and allow air into the cylinder or does it slip on the way up and allow water to blow past?

That's a very good question. From my own experience with piston slippage on a few machines (La Peppina,
Londinium and Mini-Gaggia), in this scenario, the piston gaskets can't create a good enough seal with the champer walls. Catch point is then affected and happens much higher which reduces the pressure above the puck and the volume of water inside the cylinder. Shots are usually low volume and underextracted. Whether it's air or water that slip through the seals... I'm still debating in my head!

Someone else will likely come up with the answer.
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XS750AU (original poster)
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#17: Post by XS750AU (original poster) »

Here is the video of the attempted first shot last night
Input on my work flow and any thoughts on the lack of yield appreciated.

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LObin

#18: Post by LObin »

XS750AU wrote:Here is the video of the attempted first shot last night
video

Input on my work flow and any thoughts on the lack of yield appreciated.
Thanks for posting the video! That's helpful.

Here's what I'm seeing:

Technique:
I would suggest trying to emulate the technique from the video posted by truemagellen.

-Hold the lever (all the way) down for about 10 seconds (you should probably move it closer to the edge of your counter since we can hear the handle touching the counter).
- Do a few small pumps untill you feel the lever grabbing.
- When the lever grabs, you can hold it there for a 2nd preinfusion at around 3 bars and lower the lever one more time. This help yielding larger shots and is quite efficient with modern roasts.
- No need to do a 2nd pull.
- Don't pump all the way to the top. You shouldn't have to go pass 8 or 9 o'clock when doing the small strokes. Lever grab is pretty low on this machine like 7-8 o'clock.

Some more observations:
- Seems you may need to grind finer. Choking the machine and pulling a shot by assisting the lever is a good starting point. Grind coarser from there.

- There's a squeaking noise in the video. It sounds like your piston seals need lubrification...
Also, is the inside of your piston chamber clean and free of build-ups and scale?
From the video it doesn't sound like a noisy spring or spring mechanism. Unless you guys have a pet hamster? ;)

- I have converted one of my La Peppina portafilter to bottomless. It's not the easiest PF to convert and it looks a bit weird but it definitely helps being able to see what's happening underneath the basket.

Hope this helps!

Cheers!
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yakster
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#19: Post by yakster »

I would take the lid off the kettle and check to see if you see any water re-entering the kettle during the pull. The La Peppina uses two flapper valves (rubber washers) with an upside-down piston between them. When you pull the lever down, the flapper valve in the group shuts and seals and water is drawn through the flapper valve from the kettle. When you let the lever raise then the flapper valve leading to the kettle closes and forces the water out of the group through the group flapper valve. If the flapper valve leading to the kettle isn't making a good seal then some water will flow back into the kettle and not into the cup. You can help this somewhat by making dramatic lever movements that will help snap the flapper valves shut, quickly pulling down the lever and after pre-infusion pulling the lever up a bit to snap the valves shut.

As mentioned, a bit of lever oil on the lever bearing and linkages under the La Peppina will probably help with that squeaking. Once you've got that taken care of you'll probably feel better about making snappier lever movements too.

Another trick that I use is that I slide the La Peppina up to the edge of the counter so that when I pull the lever down I can pull it all the way horizontal with the angled part of the handle hanging below the counter for a bit of extra volume.

I don't see any signs of a bad piston gasket. You'd see water under the La Peppina if the flapper valves were working properly and water was getting past the piston gasket.
-Chris

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yakster
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#20: Post by yakster »

When you pump the lever up and down with the kettle lid off you should see the water being drawn into the cylinder by the piston and shouldn't see much backflow back into the kettle. If it's drawing well into the cylinder then the piston ring is probably fine. If it hardly draws any water into the cylinder and doesn't have much backflow I suppose that air could be getting past the piston seal preventing the piston from being very effective at pumping water.

I see it as one of two scenarios, either the piston is pumping water effectively and the flapper valves are not doing their job directing the flow of water or the piston is not pumping water effectively due to the piston seal.

My money is on the flapper valves.
-Chris

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