# Are levers more forgiving...



## TomHughes (Dec 16, 2019)

...with fresh roasts?

Just wondering as this is something I have noticed since moving from the Sage. 
I roast most of my stuff at home, and sometimes I forget, so occasionally I HAVE to dig into a coffee after a day or 2 as I've run out!

On the sage this was generally a bad experience, all gas and no substance, bitter roasty flavours or weak underextracted sourness.
But not with the Pavoni!

For a number of reasons I think.

The ability to have a long pre-infusion, this seems to stop the massive CO2 release from a super fresh bean from disrupting the extraction. No idea where it goes but it seems more manageable 
The ability to pressure profile, again by ramping up or down pressure it seems to make extraction controllable in these situations. 
Temperature, I can seem to get around some of the underextracted sourness in a lighter roast that hasn't rested long by ramping up the temp.

Interestingly, this seems to have an end point of around 7-10 days, at this point that same high temp causes a sudden increase in bitterness as the bean is now more extractable??

Case example.

A Yellow bourbon I roasted 10 days ago, I have spent the last 4-5 days hitting it with 95-97C and getting some lovely fruity flavours. But the last couple of days it has suddenly turned bitter. 
So I tried extracting it at what I think is 93 based on thermocouple experiments and it's now bang on where it was. 
This happened with a Guatemalan before but I thought it just might be the machine.

Anyway, thought I'd share that. I love the manual control of the Pavoni compared to the hit or complete miss approach of the sage.


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## Mrboots2u (May 10, 2013)

I can do long , low flow, pre infusion On a pump machine , to be honest I experience no benefit to using it with fresh coffee .


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## TomHughes (Dec 16, 2019)

Mrboots2u said:


> I can do long , low flow, pre infusion On a pump machine , to be honest I experience no benefit to using it with fresh coffee .


 Can yours get rid of the CO2 after the bloom though or is it a closed circuit? I guess the pressure profiling also plays a role


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## Mrboots2u (May 10, 2013)

TomHughes said:


> Can yours get rid of the CO2 after the bloom though or is it a closed circuit? I guess the pressure profiling also plays a role


 How would one get rid of the co2 , I'm lost


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## TomHughes (Dec 16, 2019)

Mrboots2u said:


> How would one get rid of the co2 , I'm lost


 As in on the Pavoni where you can apply the pre-infusion then release the pressure, allowing the CO2 to escape back up into the group head. 
At that point it will either become part of the extraction volume, meaning the pull will be spongy and the shot volume will be low. Or you can felleni it and pump it back into the boiler and replace with water, then pull.


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## MediumRoastSteam (Jul 7, 2015)

TomHughes said:


> As in on the Pavoni where you can apply the pre-infusion then release the pressure, allowing the CO2 to escape back up into the group head.
> At that point it will either become part of the extraction volume, meaning the pull will be spongy and the shot volume will be low. Or you can felleni it and pump it back into the boiler and replace with water, then pull.


 I don't think there's that much CO2 into 14g of beans Tom. However, I do understand what you are saying in terms of ageing of the beans. When I roasted my own, I had a similar experience (documented in this forum, obviously!) where freshly roasted beans were earthy, grassy. After a good rest of 7 days, they were good. Unfortunately, I never had the opportunity of doing what you did with the Pavoni, which seems interesting. It might be, however, the simple fact that a gentle bloom per-infusion and high temperature would benefit extracting freshly roasted beans for espresso, in the same way that very freshly roasted beans used on Aeropress or V60 tastes absolutely fine. IMHO.


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## TomHughes (Dec 16, 2019)

MediumRoastSteam said:


> I don't think there's that much CO2 into 14g of beans Tom. However, I do understand what you are saying in terms of ageing of the beans. When I roasted my own, I had a similar experience (documented in this forum, obviously!) where freshly roasted beans were earthy, grassy. After a good rest of 7 days, they were good. Unfortunately, I never had the opportunity of doing what you did with the Pavoni, which seems interesting. It might be, however, the simple fact that a gentle bloom per-infusion and high temperature would benefit extracting freshly roasted beans for espresso, in the same way that very freshly roasted beans used on Aeropress or V60 tastes absolutely fine. IMHO.


 I think that last part was the gist I was going for!


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## Mrboots2u (May 10, 2013)

TomHughes said:


> As in on the Pavoni where you can apply the pre-infusion then release the pressure, allowing the CO2 to escape back up into the group head.
> At that point it will either become part of the extraction volume, meaning the pull will be spongy and the shot volume will be low. Or you can felleni it and pump it back into the boiler and replace with water, then pull.


 I can stop all flow going into the group head , but there will be water creating pressure in the puck already which I would have thought me at nothing can escape . 
same for a patio I surely as you are not sucking water out after pre infusion


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## TomHughes (Dec 16, 2019)

Mrboots2u said:


> I can stop all flow going into the group head , but there will be water creating pressure in the puck already which I would have thought me at nothing can escape .
> same for a patio I surely as you are not sucking water out after pre infusion


 I don't follow.

Firstly, I was led to believe that one of the reasons very freshly roasted beans were hard to get right on the extraction was due to CO2 release (Matt Perger mentioned this, as well as an SCA lecture on extraction)

On the Pavoni as you bring the lever up it uncovers the hole to the boiler letting water come in at boiler pressure +1bar. 
This then hits the coffee to pre-infuse at say 1.7bar. 
If the coffee is super fresh then you will get a release of CO2 right? but this is at low pressure, a bit like pouring a V60. 
At that point you can release the pressure and lightly pump the lever the air in the group is forced back into the boiler, this in theory could include a small amount of CO2, hence why when I do this I get much less crema.

In addition to being able to pressure profile on the fly based on whats happening with the extraction I think this ends up with being able to control a fresh roast better.

Does that make sense?


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## Mrboots2u (May 10, 2013)

TomHughes said:


> I don't follow.
> 
> Firstly, I was led to believe that one of the reasons very freshly roasted beans were hard to get right on the extraction was due to CO2 release (Matt Perger mentioned this, as well as an SCA lecture on extraction)
> 
> ...


 Makes sense , not sure it will negate the effect from fresh roasted beans for espresso .

yes I can do this on my bianca , it's a kind of blooming espresso , shut off all flow from the puck , but how does the co2 escape the puck is covered with water at pressure at say 1 bar in a sealed environment


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