Tutorial on static electricity in grinders - Page 3

Grinders are one of the keys to exceptional espresso. Discuss them here.
toobs1234 (original poster)
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#21: Post by toobs1234 (original poster) »

Buttercup wrote:So, a couple of things:

What about static with a Hario Mini Mill Slim? (Ceramic burrs).

And why does everything respond with 3-4 drops of water in 25g of beans with a nearly complete dissipation of static?
Ross Droplet Technique-Eliminating Grinder Static
It's difficult to predict how much static the ceramic burrs will generate. It depends on where the ceramic lies on the triboelectric series relative to the beans.

You don't need to soak the beans in water, you just need a 1 molecule thick coating on the surface. The water molecules don't even need to be adhered to the surface, they can be suspended in the air too. They just need to be located in the gap between grind and burr in order to help the electron bridge the gap.

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FotonDrv
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#22: Post by FotonDrv »

Terranova wrote:+1


Lets try to find a way to neutralise these little animals, destroying our mood on a monday morning. :)

Will it make a difference to fit a lower funnel in steel, connected to a metal wire which is grounded to the sink or so ?
Or do you habe another practical suggestion which is worth it, trying out.
In 2 weeks time or so I get my hands on a HG One, which I cannot take apart (it's not mine) , but just changing the funnel is quiet ok.
It has also been mentioned, some beans are prone to produce more static, but this is more because of coffee being very hygroscopic, translated: it exchanges watermolecules, gives them up to the atmosphere or absorbs them, depending on relative humidity surrounding the grinder.
It is worth a try.

Cheers

Frank
Hey Frank! I just ground through 1-1/4 pounds of beans with my new HG-1 83mm #099. Static is very bean dependent and I too suspect age of bean/hygroscopic nature of them. Some older beans had zero static retention and some new fresh beans exhibited a lot of static.

I did not try the RDT yet but that is for tomorrow. My arm is tired.

Cheers,
Stephen
That Light at the End of the Tunnel is actually a train

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orphanespresso
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#23: Post by orphanespresso »

As noted from the replies, queries, theories, and suggestions static produced through coffee grinding is a very difficult thing to wrap one's mind around. Static can be produced with ceramic burrs. In fact static is ALWAYS present, it is just sometimes not detected as it is either transitory or eliminated through physical manipulation.

Static is produced in my abrasive blast cabinet to an amazing degree with no grinding burrs, etc...it comes from the simple movement of small particles through the air. In the case of the HG1 there are a number of design elements which are compounding to cause the static to be produced yes, but more importantly not be allowed to dissipate readily, and be VERY observable.

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FotonDrv
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#24: Post by FotonDrv »

Doug:

How would you reduce static in the HG1?

Stephen
That Light at the End of the Tunnel is actually a train

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orphanespresso
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#25: Post by orphanespresso »

I generally agree with the idea that if a couple drops of water tames the static...problem solved! Even turning slower seems a help.

The problem is that another grinder on the same counter with the same beans does not show the same level of static cling. What is likely, IMO, is that static is equal in the two grinders at the burr level but is not detected in the one but is seen as a feature of the other. I think that the shape of the lower funnel is one issue and the non conductive coating is another...but with static, conductivity is not as big a deal as use of materials that have the ability to allow these charge imbalances to equilibrate as fast as possible. A glass lower funnel would likely do the job. The water added is acting a bit like a catalyst for the neutralization of the charge imbalance to take place. Our next grinder will have no plastic or negative tribo electric parts at all below the burr and we think this will fully solve the static problem...as long as one is holding it in one's hand while turning. That is another small static enhancer with the HG1....both hands grip to plastic so your body cannot lend its relatively large surface area as a static sump.

Barb actually has a better intuitive grasp of this than I do, since she is neither a scientist or an engineer she does not over think the whole thing.

toobs1234 (original poster)
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#26: Post by toobs1234 (original poster) »

"...but with static, conductivity is not as big a deal as use of materials that have the ability to allow these charge imbalances to equilibrate as fast as possible. A glass lower funnel would likely do the job."

this seems counterintuitive to me. Can I get you to explain a bit more?

thanks, John

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FotonDrv
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#27: Post by FotonDrv »

Doug:

Excellent explanation, as usual :D

I tried using a glass catch basin (a large Bodum cup) and wow did that ever increase the static coming from that aluminum cone! The glass extended a bit above the bottom of the cone and the static cling drew grounds about half the way up the outside of the cone!! I will not do that again...

Just as it come the static cling is easily remedied with a tap on the outside of the cone but today I will use the same beans and try the RTD; note to self, buy mister.

I had not considered the plastic handles! I can see I will be busy turning some aluminum ones, or maybe stainless if I can find some locally. I might have to resort to mail order for material :shock:

Today I will try grinding barefooted rather than in stocking feet to see if that makes a difference but I suspect not. I grind next to a sink and I ground myself before grinding.

Thanks again Doug.

Stephen
That Light at the End of the Tunnel is actually a train

Seacoffee
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#28: Post by Seacoffee »

Stephen,

What about putting left hand on gear housing instead of the steady handle. At least then you have grounded yourself the to metal

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JohnB.
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#29: Post by JohnB. »

FotonDrv wrote:
I had not considered the plastic handles! I can see I will be busy turning some aluminum ones, or maybe stainless if I can find some locally. I might have to resort to mail order for material :shock:
Save your time. The handles are already aluminum, not plastic.
LMWDP 267

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uscfroadie
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#30: Post by uscfroadie »

orphanespresso wrote:That is another small static enhancer with the HG1....both hands grip to plastic so your body cannot lend its relatively large surface area as a static sump.
Doug,

The handles on the HG One are not plastic. In fact, the only thing on the grinder that is not metal is the rubber feet.
Merle