Tutorial on static electricity in grinders - Page 6

Grinders are one of the keys to exceptional espresso. Discuss them here.
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#51: Post by civ » Feb 23, 2013, 10:37 am

bdbayer wrote: ... air purification is usually done with negative ...
IF you only have one polarity you are adding charge.
Makes sense.
bdbayer wrote: If the unit you have pictured only generates negative ...
By the description on the web page, that's what it does.
bdbayer wrote: ... probably just hooked to one side of the AC circuit.
There's only two leads.
I've read on the web about a kit (Heath type thing) to build an ion generator that can be used to emit positive 'or' negative ions, depending on how the polarity of all the diodes are set up.

Bun not both alternatively or at the same time. =-/
bdbayer wrote: ... wonder if the same device would generate positive if hooked to the opposite side of the AC line.
Might be something to ask an electrician.
No idea how I'd do that. As far as I know (corrections welcome), AC voltage is a sinewave and at line frequency (50/60Hz) will go back and forth from + to - (or something like that).
bdbayer wrote: ... Zerostat has really gone up since my days ...
Indeed ...
In my days, which are probably the same as yours, it was also a rather expensive thing to have around.
The guy who had an AR turntable, a Rabco SL8 with a Pickering cartdrige and a a Zerostat was king of the neighbourhood. =-)

What would be needed is an AC powered Zerostat-like device, small enough so as to be able to keep it inside the grinder body with the emitters pointing into the funnel.

Thanks for your input.



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#52: Post by bdbayer » Feb 23, 2013, 12:15 pm

What would be needed is an AC powered Zerostat-like device, small enough so as to be able to keep it inside the grinder body with the emitters pointing into the funnel.
That's the type of stuff I sell but I have been trying to avoid promoting products or the company I rep.

It would an require an AC power supply box located somewhere out of site with a "one point ionizer" or very short static bar located in the path of the coffee grounds.

Cost is still an issue though, this setup would still be $450.00 for the one point to over $1000.00 for a bar and power supply, they are designed for industrial applications where you can justify ROI.

Barry Bayer

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#53: Post by bdbayer » Mar 01, 2013, 10:17 pm

Please don't let the fact that I sell this stuff stop the discussion.

I'm not trying to sell anything, just trying to lend a little professonal knowledge to the topic.


crusty cup

#54: Post by crusty cup » Mar 02, 2013, 2:47 am

I think the elegant solution has already been proposed - the addition of a small amount of moisture.

After that, the addition of a few grounded needles in the chute might be effective. It looks like static control on the K30 is just a ring of points right where the chute meets the grind chamber.

Some air ionizers have an AC source. One of those could be gutted and the electronics could be installed in the chute or in the doser.

In view of the fact the chute is so small, and the fact that the electric field strength is what is important, not the potential - maybe only 1kV would be required to neutralize the charge on the coffee, as long as it was done in the chute. A homebrew circuit would be easier at 1kV than at 5kV.

All this stuff in the doser or chute is going to become a impediment to keeping the equipment clean though. I guess the professional solution is something like the Simco Sidekick - sometimes these pop up on ebay for around $200. It needs a source of compressed air though, and it won't look so smooth in the kitchen.

How about roasting the coffee to a darker level - more carbon, more conductivity. :mrgreen:


#55: Post by flyguyjake » Mar 03, 2013, 3:36 am

I do see that there is a ground wire connected to the k30 chute.

Isn't this why the M3 has the copper wire & copper wiper arm?


#56: Post by cpreston » Mar 03, 2013, 5:39 am

On my M3 the static (as in fixed, not electrical) wiper looks like stainless wire. Still quite conductive. But I think it's intended for clearing grinds.

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#57: Post by Terranova » Mar 03, 2013, 7:47 am

flyguyjake wrote: Isn't this why the M3 has the copper wire & copper wiper arm?
The "static wiper" is made of spring steel and the moving wiper is made of brass.
cpreston wrote:But I think it's intended for clearing grinds.
That is right


#58: Post by Netphilosopher » Mar 04, 2013, 11:28 am

FWIW, interesting thing I found with my LIDO.

Untreated coffee ground in a dry environment with tons of static = more fines. It appears that the static has a tendency for some of the ground coffee to slow down or backup the flow through the grinder.

I found this out three different ways:

1) Noticed that high static CCD brews had longer percolation time (lower percolation rate).
2) Noticed there was more "mud" in the brew basket with high static grinds.
3) Noticed that at the end of grinding a batch, I shake the grinder and grind any straggler beans. I also pull the center shaft to knock anything out - and do another couple cranks. With static, there is ground coffee stuck between the burrs that resists shaft motion, and it takes some time to get these bits loose.

I've also honed in on the amount of water, it's really small. about 16g needs only 1 drop (and subsequently shaking the beans before tossing them into the LIDO). About 50% of the time, I can get away with 1 drop on 22g, but I usually use 2 just to make sure.