To make butter, you start with cream, which is basically droplets of fat separated by a small amount of water. The droplets of fat do not merge because they are coated with milk proteins. Churning bashes the fat droplets into eachother until their protein shells are broken and the droplets merge and join together, giving you a sea of fat with little droplets of water trapped in it. This process is called "inverting an emulsion" (the oil-in-water emulsion of cream is inverted to become a water-in-oil emulsion of butter).

Now.

I've been playing with microfluidics, and specifically with water droplets carried along in a stream of oil. Surfactants are used so that, even when two water droplets touch, they don't merge. But, by applying a modest voltage across a pair of droplets, they can be induced to merge, because the back end of one droplet picks up a negative charge, and the front end of the adjacent one picks up a positive charge, and so they attract and break through the layer of surfactant that separates them.

So.

It should be possible to turn cream into butter by applying a voltage across it, instead of by all that tedious churning. For a large vat of cream, quite alarming voltages would be needed, but only for an instant. Lightning should be more than adequate.

At this point, a well-thought-out idea would explain why this would be a better way to make butter than the conventional approach, but this is not a well-thought-out idea. Therefore, I will stop here and leave you with the concept of a lightning-powered instant buttermaker.
-- MaxwellBuchanan, Apr 22 2010

The target demographic http://en.wikipedia.org/wiki/Sif
[mouseposture, Apr 22 2010]

//Lightning should be more than adequate.// But what sort of power levels do you get from a bolt of lightning? http://www.youtube....watch?v=mjCRUvX2D0E
That should be enough! [Jinbish, Apr 28 2010]

Pulsed Electric Field (for sterilisation of food) http://www.epsrc.ac...s/foodelectric.aspx
"Just like humans, bacteria such as E. coli can be killed by a jolt of high-voltage electricity." & [Jinbish, Apr 28 2010]

Sif <link> would use this.
However: wouldn't heat denature the whey protein?
-- mouseposture, Apr 22 2010


Why do I suspect that you will have lots of burnt and scalded cream using this method?
-- jurist, Apr 23 2010


I don't understand why alarming voltages would be needed for a large vat.
Wouldn't many small voltages work better? Like raising a charged mesh through the cream maybe.
-- 2 fries shy of a happy meal, Apr 23 2010


parfait
-- Mustardface, Apr 23 2010


I'm tempted to test this at home using 120V household power. Any idea how much cream could reasonably be buttrified without tripping my breakers?
-- gisho, Apr 27 2010


What a coincidence - I was marking a student project recently: "Characterisation of non-insulating liquids" - yadda-yadda...something "breakdown voltage".

It was basically a vat with an electrode & plate arrangement to test out various combinations of natural oil for use in transformers. If only it wasn't exam time, I'd hunt the student down and tell him to redo his experiments but with full cream milk instead!

{Except, sadly, I know that the results will be poor - both for insulating material, and production of non-burnt butter.}
-- Jinbish, Apr 28 2010


Lightning is an unpleasant beast. Trying to harness it for voltage alone will see the voltage rise to the point that it happily delivers current. Lots and lots of current.

This may at first seem to be a bad thing, but if sufficient amounts of bread are lined up on racks around the butter making machine and that itself is built to survive - the voltage will rise, butter will be made, then current will form an arc and toast will result.

All in all, from milk and soggy white bread to fresh butter and lightly browned toast in less than a millisecond.

The loud report of the toast making arc should do well for an alarm clock too.

To time the whole system presumably one needs to anger Thor just before needing to wake up. Dreaming of Freya should do the trick...
-- saedi, Apr 28 2010


As I know almost nothing about science I shall take Max's basic proposition at face value and posit that if you attach a lightning conductor on the shoulder of your cows (assuming that you own some that is) and attach an earth cable to their udders then, when an electrical storm is imminent, you can drive your cows out into an open field where they willl attract lightning strikes and have cows that produce butter 'naturally'.
-- DrBob, Apr 28 2010


It should be possible to test [Max]'s hypothesis by comparing the butteriness of milk from cows grazing in fields with and without electric fences.
-- hippo, Apr 28 2010


Intuitively I can't help thinking that applying a lower voltage gradient for a longer period might have the same effect as applying a high voltage gradient for a brief period - though admittedly this is a gut feeling, not based on any sound knowledge of the principles.

Making butter takes a while anyway, so why worry about trying to do it in a fraction of a second? Maybe you could speed the process up considerably in a much simpler way.
-- Wrongfellow, Apr 28 2010


//a lower voltage gradient for a longer period might have the same effect//

I'm not sure - I think that would just electrolyse the watery part of the butter and do something nasty to it. You need a sufficient voltage to ensure that adjacent droplets become polarized like this:

[+] (+-)(+-)(+-) [-]

where the square brackets are the electrodes, and each ( ) is a fat globule, with a charge difference across it. The charge difference between one droplet and the adjacent one (that is, the -)(+ part) has to be big enough to cause enough attraction between the droplets to break down the protein layer that normally stops them merging.

As to why the process needs to be so fast....imagine the possibilities! You could create a massive cream fountain or cream waterfall, and instantaneously solidify it into a butter sculpture! This is clearly a technology that fills a much-needed gap.
-- MaxwellBuchanan, Apr 29 2010


Ah, OK, that makes sense.

I can certainly see advantages to being able to instantly solidify liquids. This could revolutionise the study of fluid dynamics, or the process of taking a casting and making a mould.
-- Wrongfellow, Apr 29 2010


It's astonishing that this thread of annotations has got so long with no one mentioning Van de Graaff generators.
-- hippo, Apr 29 2010


So you think Van de Graaff generators are a match for lightning?
-- pocmloc, Apr 29 2010


A very big one would be - 1km high with a 200m diameter ball on top...
-- saedi, Apr 30 2010



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