# New idea about preinfusion



## Mad Wally (Feb 24, 2016)

I found the following on http://coffeesnobs.com.au

"Iv'e played around with different pre-infusion methods on Silvia and I agree that I wasn't able to find one that benefited the coffee. Pulsing the button or having the steam wand open just added more difficulty without any obvious differences in the cup. But to say that Pre-infusion is just internet hype?

It depends on how the pre-infusion is implemented. On higher end machines Slayer/Strada/Hydra it completely changes everything. An 8-10 second 2-4 bar pre-infusion facilitates the use of a much, much finer grind. It changes the way fines migrate through the puck (no more fast/slow/fast espresso pours) It serves to round off the acidity in brighter coffees and improves body, it facilitates the use of lighter roasts and larger doses. It's another tool which I have found improves the taste of most coffees.

On a silvia its going to be very hard to replicate this, the only way I can think would be to use some kind of voltage controller on the pump and have a pressure gauge also installed to tell you whats going on. This is just theory though. It probably wouldn't work to make the coffee better."

What if I were to add a 2nd OPV set at 2 bar with a valve (manual or automatic)?

That way I could start the shot with the valve open and the low pressure OPV controlling the pressure at 2 bar for 8-10 seconds and then close the valve and have the regular OPV control the pressure at 9 bar?


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## Mrboots2u (May 10, 2013)

Ive seen to OPV added to a rocket before to do something similar but i have no idea if that would be compatible with a sliva ( sorry just not technically minded enough )

There are PID's that pulse the pump for " pre infusion "

if you dont have a pid then im not sure what the value of doing this would be as you would get far more benefit from having a stable temp than faux pre infsuion


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## Mad Wally (Feb 24, 2016)

Mrboots2u said:


> Ive seen to OPV added to a rocket before to do something similar but i have no idea if that would be compatible with a sliva ( sorry just not technically minded enough )
> 
> There are PID's that pulse the pump for " pre infusion "
> 
> if you dont have a pid then im not sure what the value of doing this would be as you would get far more benefit from having a stable temp than faux pre infsuion


I did the PID the same day I bought Silvia but am now looking to improve further.

And why would the preinfusion be "faux"? It is just a matter of controlling the pressure buildup to the puck regardless if the machine costs 600 or 6000 euro.


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## Mrboots2u (May 10, 2013)

Mad Wally said:


> I did the PID the same day I bought Silvia but am now looking to improve further.
> 
> And why would the preinfusion be "faux"? It is just a matter of controlling the pressure buildup to the puck regardless if the machine costs 600 or 6000 euro.


By faux i was reffering pump pulsing with a pid ( or not ) ....although i think this is what the linea mini does to be honest - @DavecUK care to comment


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## Mrboots2u (May 10, 2013)

Have you seen this btw


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## oursus (Jun 5, 2015)

Mrboots2u said:


> Have you seen this btw


I was looking at this yesterday while ruminating pre-infusion (also Silvia & PID with pump voltage & pause)

Only thing I came up with was "mmmm e61" chocolate fire guard, just a magpie at heart


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## DavecUK (Aug 6, 2013)

Mrboots2u said:


> By faux i was reffering pump pulsing with a pid ( or not ) ....although i think this is what the linea mini does to be honest - @DavecUK care to comment


I don't really know enough about what the Linea does....if that was the question?


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## Mrboots2u (May 10, 2013)

DavecUK said:


> I don't really know enough about what the Linea does....if that was the question?


Sorry I wasn't very clear - I was asking around the OP s idea of utilising x2 OPV to create pre infusion and it being a matter of just controlling pressure build up to the puck


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## DavecUK (Aug 6, 2013)

Mrboots2u said:


> Sorry I wasn't very clear - I was asking around the OP s idea of utilising x2 OPV to create pre infusion and it being a matter of just controlling pressure build up to the puck


Well it's a good idea, with just one tiny problem (well a few problems actually)...

1. because the pump isn't being controlled, it won't half have a good flow rate at 2 bar

2. The expansion valves don't really work down at those pressures, some will go no lower than say 5 bar, others will leak. adjuster fall out etc..

3. if you do get one that works (unlikely), spring tension will be so low, I think it might fluctuate a lot.

Might be an idea to bite the bullet and just get a better machine.


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## Mad Wally (Feb 24, 2016)

DavecUK said:


> Well it's a good idea, with just one tiny problem (well a few problems actually)...
> 
> 1. because the pump isn't being controlled, it won't half have a good flow rate at 2 bar
> 
> ...


1 pump works fine at low pressures just a big more flow but that would be diverted through the opv

2+3 opv valves can work fine at 2 bar. Professionally I use opv's from 50 mbar up to 500 bar. Just a matter of selecting the right one (with the right spring). We even use some that can maintain the pressure at 1 bar +/- 1 mbar. Costs more than a dual boiler though...


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