The matter of static causing clumping while grinding beans has been discussed recently in the Forum. An article in the Daily Telegraph today (7/12/23) sheds more light on this. I have copied it below. Maybe a light water spray isn't such a bad idea after all. I have achieved similar results with a small deioniser (see also Dave's posts on this) but it seems that a water spray might improve the degree of extraction in a way that deionising won't. Secret ingredient for better coffee revealedBy Joe Pinkstone SCIENCE CORRESPONDENT **The Daily Telegraph** 07 Dec 2023 SPLASHING water on to coffee beans before grinding could be the secret to making the perfect cup of coffee, a study has found. It is a common technique favoured by baristas hoping to keep their station tidy, as the water creates less mess. Now, a study from Oregon University which drew on the science of volcanic activity has found spraying water on beans before putting them in the grinder reduces the amount of static electricity on the particles as they pass through the machine. This not only reduces clumping and makes clean-up easier, but it also creates a finer dust which increases surface area and therefore allows for more flavour to be extracted from the beans. Dr Christopher Hendon, associate professor of chemistry at the University of Oregon, set up a coffee lab on his campus two years ago and volcanologist Dr Josh Méndez Harper was a regular visitor. Dr Méndez Harper’s expertise in the movement of molten rock, geological activity and rising magma meant he knew that when ash and rocks spewed out of a volcano they rubbed together and create static, which can result in lightning strikes. “It is similar to grinding coffee, where you’re taking these beans and reducing them to fine powder,” he said. The pair investigated if the process of spraying water on to the beans before grinding can stop the static forming. They found the technique was effective at stopping charge building up and improved flavour and the strength of an espresso. “Because the static doesn’t form, the particles also do not clump. Clumps pose problems during extraction because less surface area is available for water contact,” Dr Hendon said, adding: “By having more available surface, you end up with less wasted but extractable mass left in the coffee particles after brewing. “As a result, by grinding with a small amount of water, you end up accessing something like 5 to 15 per cent more soluble material.” If everyone in Europe sprayed water on their beans when making a cup of coffee it could stop product worth £200 million being wasted every year, Dr Hendon said. However, the team warned that while grinding and spraying can boost flavour, the benefits will not be realised without careful calibration of a machine to exploit the finer grind. The study is published in Matter. To make a perfect cup of coffee, learn from the volcano. So say a group of volcanologists. No doubt they see everything through magmatinted spectacles. But static electricity does seem to be a thing that an erupting volcano and a coffee grinder have in common. Particles in a volcano’s smoke plume rub against each other, sometimes producing lightning from the electricity generated. Coffee grinders similarly create static, making the grounds stick together and flavour the brew less. The answer is to splash a little water on the beans first to discharge the static. A flaw in the scientists’ advice is that the majority of coffee drinkers in British homes do not grind beans. They make coffee from instant powder, ground coffee or those expensive capsules. For the best Eyjafjallajökull effect, they’ll have to be converted to beans. Shared via PressReader

My only question is, if you dampen your beans does that not cause more of the grinds to clogg up the burrs which would mean having to take them out and cleaning them more often? Not that that is a problem for me as doing that for the Niche is a breeze. But for some it might be more of a faff.

Not sure about that. I used to do it this way and I didn't notice any clogging. I used a very light fine spray onto the beans in a small old syrup pudding cup which I used to weigh the beans and then gave the beans a good stir before tipping them into the grinder. Others have commented that it could cause rust on the burrs but I didn't notice this after doing it for a few weeks. According to the article it seems that the increase in humidity is as important as, or maybe more so as they didn't seem to do controls using a deioniser alone, stopping the clumping. Maybe others with better palates than mine might do some tests with deionising and water spray to see if there is a difference in the taste of the coffee. Dave C said deionising doesn't affect the taste. As usual - more questions than answers,

It appears the study did look at ionisers a bit but this report doesn't comment on any effect on the taste. https://www.washingtonpost.com/science/2023/12/06/coffee-grinding-science-static-droplet/

Already a thread on it here: https://coffeetime.freeflarum.com/d/2236-new-grinding-technique-for-perfect-espresso/13

https://www.youtube.com/watch?v=nLnB99VJ0HE

Static affecting ground coffee

MBdoc

There are a lot of comments after the Washington Post article. Many are pretty inane. Common in ‘general’ forums in my experience. Happily very rarely on this one.

FadedFrontiers

MBdoc It appears the study did look at ionisers a bit but this report doesn’t comment on any effect on the taste.

Ionisers are typically directed at the grounds rather than beans pre-grinding, so by then it’s too late.

Plus the paper suggests electric ionisation does not reduce the charge - so doesn’t have the same effect as water, even if it were applied before or even during grinding:

Because both tribo- and fractocharging may originate from electronic ionization, nuclear ion transfer, or a combination of the two,⁵⁷ we further developed an experiment to suppress ion transfer through the inclusion of ions directly into the wetting solution. If ion transfer is an operative mechanism, the inclusion of salt water should produce markedly reduced charging, dissimilar to that of pure water. Figure 6B reveals that the inclusion of NaCl, at either 0.5 or 1.0 M, shows the same fractoelectric charge reduction as that of pure water. These data lead us to conclude that ionic electrification is likely not the mechanism of charging in coffee but rather electron transfer.

MBdoc

A good point about the isocharge nature of the ‘static’. Maybe I will return to spraying.

NB to DaveC - are you still using ioniser or have you reverted to spraying?

FadedFrontiers

MBdoc A good point about the isocharge nature of the ‘static’. Maybe I will return to spraying.

I guess there’s no harm in doing both to keep things less messy, especially with those grinders where Ionisers are built in.

Systemic

MBdoc

Thank you for this link.
Having played with a small pocket ioniser for a while (Eureka Mignon 2grinder converted to single dose with bellows) I initially found it seemed to stop clumping but latterly it doesn’t seem to and I still get quite a bit of grounds stuck on the outside of the chute. I will go back to water spray again once I have emptied the shower cleaner spray again ( it produces a nice even fine spray).

JHCCoffee

I had a Eureka Mignon Specialita and found that it had a static issue. If you like the Mignon then get an Ionizer, as its a bitch to fully open up and fully clean!

I sold my Mignon and bought a Niche Zero for that and a whole host of other reasons, but that’s a topic for another post. Love my NZ and never looked back.

MBdoc

Since returning to a light water spray (about0.3-0.5G as recommended by James Hoffman) I find that clumping is slightly less than with the ioniser and there is less scatter of fine grind on the outside of the spout than with the ioniser. Don’t notice any difference in the taste of the coffee.

MBdoc

I bought a couple of little spay bottles from Amazon which arrived yesterday. A big improvement over a few drops from a spoon or my other, rather coarse spray. Much less sticking in the grinder funnel and no clumping in the dosing cup. I won’t bother with the deioniser any more.

coffeebymike

It looks like I’ve found something interesting on this topic, so I wanted to share it with everyone. Not only does this article dive deeper into the Ross Droplet Technique, but the author also tracked down who first brought it up online. Apparently, this was discussed back in 2005 in the alt.coffee community (Google Usenet), if anyone remembers that. Overall, it’s pretty fascinating.

Adrianmsmith

coffeebymike your site?

coffeebymike

Adrianmsmith your site?

No, I found this link on reddit

MBdoc

Since I replaced my grinders with Eureka Oro Zeros I have found that using CDT or deionisers made little difference to either retention , clumping or adhesion of grounds to the dosing cups. The converted Mignon which just had the hopper replaced by the Oro SD hopper and bellows wasn’t nearly as good and there was still a lot of ground adhesion in the exit spout and dosing cup. I don’t understand why this should be so as both types of grinder have heavy metal casings and spouts which are earthed.
Very odd but much more convenient not to mess about with CDT before grinding or deioniser during.

dfk41

MBdoc Some grinders have developed, some grinders have not. I think the grinder market has developed far and beyond any other aspect of coffee. Eureka have not changed their target market, or really kept up to speed with changes. It is often worse in the colder months di=ue to central heating being on. I am sure Dave will give us a technical answer as to why retention in general moccurs on some grinders and not on others…..

MBdoc

You may be right dfk41.
However the difference in the output grounds from two Eureka models I have used was striking and confirmed when I changed the original Mignon to another Oro.
There is a very marked difference in the way the grounds clump and adhere to the metal dosing cup (which is not grounded on the Oro as it sits on a wooden platform whereas on the original Mignon it sits on the grounded metal base of the grinder)

JimmyP

MBdoc Yeah, I’m a big fan of spraying with water and living in a draughty old barn I’ve noticed a big difference in preparation depending on the weather.

MWJB

For beans that are prone to static, I prefer to drop the water from the handle of a teaspoon & stir the beans, rather than spray. Spraying can leave excess moisture in the dosing cup, to which beans are more likely to stick, likewise in the grinder hopper.

MBdoc

When I was spraying I used a very fine spray and about two small puffs into a small plastic cup which I used to weigh the beans on the scales, then a quick stir before I tipped the beans into the grinder hopper. There was never any stickiness in the dosing cup but since I changed the grinders it’s just the same without the faff of spraying etc.

JHCCoffee

When the weather gets colder and the heat comes on, the dryness causes static. So I then use a fine spray bottle. But I don’t like the wetness in the dosing cup, so I may retry a wet spoon.

The water doesn’t adversely impact my Niche Z though, which remains pristine (I do a deep clean every 3 to 6 months).