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I am making carotene butter by mixing clarified butter and carrot juice.

The idea is that I now need to separate the carotene infused butter from the juice. The only problem being that they are very well emulsified together.

I tried blending it more until the heat and friction would break it, but that has not happened, even after more than 5 minutes of blending on high (my blender's limit. I tried heating the liquid to a boil but this did nothing either. Lastly, I tried decanting it, but it barely separates even after a long time.

How can I break the emulsion?

user110084
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JS Lavertu
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  • Just out of curiosity, why are you trying to break the emulsion? Are you trying to get the water from the juice out while leaving the carotene in the butter? – Joshua Engel Jun 05 '17 at 18:03
  • Yep exactly. I'm following a video chefsteps made a few years back. – JS Lavertu Jun 05 '17 at 18:06
  • This looks like the ChefSteps recipe: [Carotene Butter](https://www.chefsteps.com/activities/carotene-butter) – derobert Jun 05 '17 at 19:15
  • As I just commented above, its exactly that. – JS Lavertu Jun 05 '17 at 19:17
  • @JSLavertu yeah, I saw your comment and went looking for it. You ought to edit it in to your question. It helps to see the recipe you're trying to follow. – derobert Jun 05 '17 at 19:18
  • Salt is commonly used to break emulsions. The salt dissolves in the water phase and makes it more polar by adding ionic charge. The hydrophobic phase has a higher dielectric, dislikes charge, so it separates from the water, – Wayfaring Stranger Jun 06 '17 at 01:34
  • Did you not have problems with brown juice and melanin getting into the butter and dulling the colour? I did. – user110084 Jun 08 '17 at 14:23
  • @user110084 not really... I mixed the fresh juice less than 5 minutes after sqeezing it so it didnt brown – JS Lavertu Jun 08 '17 at 17:56

6 Answers6

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Chill it.

The butter will solidify and upon remelting the emulsion will be broken.

I've never had a butter emulsion not break after chilling.

Sobachatina
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  • I'll try this tomorrow since its already in the fridge – JS Lavertu Jun 05 '17 at 03:45
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    So you had bad luck with ice cream making all your life? :) – rackandboneman Jun 05 '17 at 13:32
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    @rackandboneman I presume "cool it off while constantly agitating it to prevent large ice crystals from forming" is not what this answer means by "chill it". – Deleted Jun 05 '17 at 14:33
  • I thought there were other methods for making ice cream by just chilling a mix, but I don't know whether that's a method that works specifically with butter emulsion or not... – Shotgun Ninja Jun 05 '17 at 19:15
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    Notice I wrote: "upon remelting". The emulsion of milk fat in the cream, in Philadelphia style recipes that don't employ custard or starch, can in fact break when the ice cream thaws. – Sobachatina Jun 05 '17 at 20:34
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    Must... not... attempt .. a ... confusing pun on the fact that for some regions, "Philadelphia" is known more as a brand of cream cheese than a US state... – rackandboneman Jun 06 '17 at 09:53
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How you break an emulsion depends somewhat on whether the continuous phase is aqueous or oily, oil droplets in water or water droplets in oil. I suspect you have oil droplets.

These are just a few methods I would try (in addition to those already mentioned earlier by users Sobachatina and fyrepenguine) if I were faced with this, but I have not tested them on your exact combination.

Adding warm or hot salt water (0.5% by weight salt in water) into it and stir

Thermal treatment: Extreme heat cycles (freezing and heating)

Particle charge disruption methods (all different methods not steps in a single method) :

  • Adding vinegar and stir
  • Dissolving agar or gelatin hot water and add to emulsion, stir and let it settle and then separate the oil from the gel (1-2% by weight)
  • Add salt (0.5% steps by weight) to gel solution above and stir into emulsion

G-force: If you have a centrifuge, there should be enough density difference between the two phases to achieve a complete separation.

Carotene has a strong preference to stay in the oil while salt, vinegar strongly prefer water.

As an aside, with aggressive agitation and when subjected to high shear, you tend to end up with a very stable emulsion. This is why my preferred way of this type of 2-phase liquid-liquid extraction is to use gentle stirring over more time rather than using a blender. Even periodic shaking is preferable. Diffusion across the interface will allow the extraction to happen with time. If you use a thermometer to monitor the temperature of the contents inside most kitchen blender, even in high speed mode, there is no heating effect from friction (except for very high power ones as pointed out in comment below), but You are very likely to create electrically charged droplets which is great if you are after a stable emulsion. Very high speed blenders capable of heating by cavitation can make the emulsion more stable than less stable. There is also the likelihood of aeration to accelerate enzymatic browning.

It is too easy to just focus on the best way to extract (small particles for high surface area and short diffusion path) in the least amount of time, and lose sight of the entire process which still requires separating the oil phase from the water phase. Extraction between two very mobile phases is relatively painless, but emulsion breaking can be painful, and you want to avoid doing one step really well only to create a hard problem for later.


In a very crude experiment today, I found that starting with pulped pressure-steamed carrot, using a gold coffee filter cone and repeatedly dripped clarified butter through with patience worked very well, no emulsion (just a layer of water phase below to decant away). In fact, if you really want efficiency, retain some carotene butter for next time, start the extraction with fresh pulp and melted carotene butter in the first couple of runs, then use pure clarified butter for subsequent once. (Counter-current extraction technique). Strictly speaking it is no longer liq-liq extraction but leaching but the concentration gradient principle is the same.


PS

This is another technique that is much more sensible/workable in a home kitchen.

Shred the carrots, finer is better but coarse shredding works well enough. You can optionally blanch this if you are concerned about browning.

Put into a bag with hot clarified butter at above 75C, expel as much air as you can or vacuum the bag before sealing. Sous vide at 75C or use a hot water bath (well below boiling) for 3 hours or longer. Decant off the now orange coloured oil phase. You can keep the carrot pulp to make crisps or discard it. If you are obsessed with extraction efficiency, cook it for a day, but I suspect numerically you would not get to the same degree as the juice/emulsion method, but then this is practically just a single extraction-separation step without any emulsion headache.

user110084
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  • I wonder if it would be easier to extract out the carotene first, rather than separating the water out from the emulsion, since the proteins in butter act as emulsifiers. Perhaps something as simple as allowing the water to evaporate from the carrot juice? – Joshua Engel Jun 05 '17 at 18:21
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    I think clarified butter should have most of the proteins taken out, but yes unclarifed butter will be messier still. Many non-aqueous solvents to pull out the carotene would have the same emulsification issue. The main culprit is the blender and high shear. Evaporation would get rid of the water but not the sugar and ash. And you will want to go gentle on the heating too. – user110084 Jun 05 '17 at 18:27
  • "If you use a thermometer to monitor the temperature of the contents inside a kitchen blender, even in high speed mode, there is no heating effect from friction," — at least with a Vitamix, that's not true; I put warm water with a drop of soap + run it on high for a minute or so to clean it, and it's steaming (and hot) when I pour it out. – derobert Jun 05 '17 at 19:10
  • @derobert, yes I am wrong on that with a few very high speed blenders which cause cavitation in the liquid. Will edit that. – user110084 Jun 05 '17 at 19:38
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    "If you have a centrifuge" I haven't gotten around to trying it yet, but [there's a neat-o homemade centrifuge that some medical workers use in the field](http://news.stanford.edu/2017/01/10/whirligig-toy-bioengineers-develop-20-cent-hand-powered-blood-centrifuge/) when they lack access to either electricity or machinery. The capacity might be too small to be useful, but worth a try. – jscs Jun 06 '17 at 11:48
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(By no means is this a method that I know will work, but it is a decent last resort)

I'm just going off of what I've learned from chemistry, but another possibility is adding salt water if Sobachatina's suggestion of chilling it doesn't work. The salt water should mix with the carrot juice, and the increased polarity should separate out the the butter. Here's a link to list of techniques (not all of them suitable for cooking) to break up emulsions.

fyrepenguin
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    That's surely going to leave salt in the final product. – David Richerby Jun 05 '17 at 07:59
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    Good point, @DavidRicherby. How much would you expect to stay in the butter, rather than separate out? I wouldn't imagine that too much should stay in the butter. – fyrepenguin Jun 05 '17 at 08:46
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    Instead of adding salt, if you add salt water, there is less of a chance for salt particles to be trapped in the oil. Salt simply will not dissolve in oil. There is still room for tiny salt water droplets getting trapped in the oil, but if the emulsion separates, then there should not be much left in the oil phase. – user110084 Jun 05 '17 at 09:50
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Just let the mixture stand for a few hours. Just like in milk, the butter should rise to the surface.

If then additionally you chill it for half an hour or so, the solidified butter should be easy to scoop off. If you freeze it it is probably not going to work.

If this does not work, you might actually have to churn it, like with milk. Shaking your container might be a good option if it is not too big.

No sweat. Or almost. LOL!

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    A good point about the churning -- it's a much different type of action than a blender would give. I think the paddle blade in a stand mixer might be a better way to mix it if you're trying to break it. – Joe Jun 05 '17 at 13:36
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    It is very perplexing why so many recipes recommend high speed blending for liq-liq extraction when you absolutely do not want an emulsion to deal with afterwards, even more surprising when they come from authors who talk so much about science of cooking and are good at that in so many other areas. – user110084 Jun 05 '17 at 14:30
  • @user110084 For the most effective liquid-liquid extraction, you want to maximize the surface area between the two liquid phases, and to maximize the time spent with this surface area. Making (or almost making) an emulsion is an effective way to do that. I'm guessing the assumption is that in most cases it's relatively easy to get oil and water to re-separate - the normal concern is how to keep an emulsion from breaking, rather than how to prompt it to. So most recipe writer aren't to concerned about making an emulsion with a blender, as "normally" they'll break on their own. – R.M. Jun 05 '17 at 20:54
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    @R.M.Appreciate the desire for large surface area and short diffusion path, it just look like accomplishing one separation only to create another which could be potentially much harder, too much brute force and unnecessarily so especially for two highly mobile phases. Time saved in extraction is lost to settling even for unstable emulsions. The entire process needs to be effective rather than just a single step. Emulsion breaking is a huge headache in too many situations. – user110084 Jun 07 '17 at 01:41
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take a small portion, put it into a small but solid container, tie it with a small cord, and let it turn in air drawing circles. Be carefull when you stop it may spill everywhere!! It's very "preistoric" centrifugation but it may works :D

lol
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Put it in a small container and shook like crazy. Butter separated easily fine the water and was very creamy. Saved 1/4 oz. Phew!