# Effects of anti-static devices when pulling a shot



## MediumRoastSteam (Jul 7, 2015)

Hi all,

I've recently bought a Profitec t64 grinder and I am still experimenting with different ways of grinding my coffee every morning in order to minimise wastage and extra steps.

So, until now (for about a month), I've been using the grinder without the anti-static screen (similar to the ones in a Mazzer Mini / Super Jolly) so I could easily sweep the chute and have relatively no retention and have been obtaining relatively good results in the cup. The grinder would dose my usual 18g of coffee into the basket, but there is a relatively considerable amount of static, but nothing too bad that can't be managed with a dosing funnel made out of a yogurt pot or similar. The grinds in the basket are nice and fluffy, no clumps what so ever. Level, tamp, pull and there it was 18g in, 36g out in about 30s.

Today I decided to try the grinder with the anti-static screen back in place, which means that coffee would back up in the chute and when the coffee is ground the new coffee pushes the coffee out instead of them flying straight out the chute into the cone, causing static. With the anti-static grind on, the coffee grinds clumped quite a bit. Regardless, I went ahead I dosed 18g into the basket, levelled, tamped and pulled the shot. 18g in, 25g out in 95s! 65 more seconds! I tried again and the exact same happened.

Does anyone know why the anti-static grid makes such a difference in terms of extraction, if the grind adjustment was unchanged? Why would one need to grind significantly coarser when the anti-static grid is in place to obtain the same brew ratio, for the same dose and the same shot time?


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## risky (May 11, 2015)

Grounds clogging in the burrs as they cannot easily exit and getting reground extra fine?


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## dsc (Jun 7, 2013)

On grinders with a dosing funnel (like the doserless Mazzer) quite often if you remove the anti-static grid / shield you get fines sticking to the inside of the funnel and only the heavier stuff comes out. It might not look like much weight-wise, but without those fines there's nothing to slow down your shots. I'd say this is probably what's happening here.

T.


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## MediumRoastSteam (Jul 7, 2015)

dsc said:


> On grinders with a dosing funnel (like the doserless Mazzer) quite often if you remove the anti-static grid / shield you get fines sticking to the inside of the funnel and only the heavier stuff comes out. It might not look like much weight-wise, but without those fines there's nothing to slow down your shots. I'd say this is probably what's happening here.
> 
> T.


Thanks @dsc. I'll keep experimenting.


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## dsc (Jun 7, 2013)

Mind you I might be entirely wrong here as well








although in my defence I have to say I've seen similar effects on a converted Mazzer Major that I once owed (and converted).

T.


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## MediumRoastSteam (Jul 7, 2015)

dsc said:


> Mind you I might be entirely wrong here as well
> 
> 
> 
> ...


I think you are quite right in your theory dsc, at least according to this article, to quote:

"...

I followed the lead of Malkoenig and Mazzer, and combined a simple polished cone with a wire mesh screen on the exit from the apeture leading to the grinding head. . I found that without the screen the coffee sprayed out of the grinder and micro particles adhered to the vertical, stainless steel wall.

..."

http://espressovivace.com/index.php/micro-particle-migration-in-conical-grinding-systems/


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## dsc (Jun 7, 2013)

This is exactly the effect I was describing and indeed one of the reasons David Schomer is a firm believer that free fall grinders are not a good idea.

T.


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## Father_Java (Apr 24, 2013)

pessutojr said:


> I think you are quite right in your theory dsc, at least according to this article, to quote:
> 
> "...
> 
> ...


Very interesting, thanks.


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