Topic: Why does the Oil "Separate" from the Curry and Base?

[Aussie Mick]

I don't have any scientific explanation, but oil and water do not mix, and cannot "blend". If a base gravy contains both oil and water, then surely at some point the oil will seperate.

[PaulP]

You're right Mick, they don't like to blend but a good example of a stable emulsion of water and oil is milk. One of the labels associated with milk is "homogenised".

The milk is forced through very fine filters that cause the fat globules to become extremely small and this is enough, in the case of milk, to create a stable emulsion.

But regarding base sauces, it doesn't really matter whether the oil separates unless you intend to skim some off for other uses. For the home cook freezing batches of base the separation is almost a nuisance as you will want to give it a good stir before dividing into smaller containers.

Paul

[Peripatetic Phil]

But regarding base sauces, it doesn't really matter whether the oil separates unless you intend to skim some off for other uses. For the home cook freezing batches of base the separation is almost a nuisance as you will want to give it a good stir before dividing into smaller containers.

Indeed. In fact, would not skimming off the oil be counter-productive, in that given that we all agree that it is the oil that is the carrier for BIR flavours (i.e., it acts as the solvent for the essential oils in the spices), would you not diminish the quality of the base if you were to skim the flavoured oil off the top ?

** Phil.

[PaulP]

I only mentioned that Phil as at least one member (JerryM) says he uses excess oil in the base and skims some off for his spiced oil.

Cheers

Paul

[Peripatetic Phil]

I only mentioned that Phil as at least one member (JerryM) says he uses excess oil in the base and skims some off for his spiced oil.  Cheers.  Paul

I wonder if Jerry adds additional spices to compensate ?
** Phil.

[h4ppy-chris]

Okay, here it is, so we can all get our heads round it.

In a base, or, a curry, there are 3 things.

1. water.
2. Oil.
3. Sustenance (emulsifying agent (emulsion mixture)= onions, spices ect.

We know oil and water don't mix. So we need a sustenance for the oil to stick to, which, then will mix with water. The sustenance is a carrier of the oil(bonded together), which then oil can be suspended in water.

De-emulsification.
The application of heat causes breakdown of the micelle bond (releases the oil from the sustenances).
Now we know oil floats on water, this is because oil is lighter then water.

So to get oil to come to the top, we need 2 things, HEAT & WATER.

Heat; enough to break the bond between oil & sustenance.
Water; enough to let the oil flow.

A good example; Madras, not a lot of sustenance, so oil can flow free-ish to the top.
                Dansak, a lot of sustenance ie; Lentils, so its harder to de-emulsify (not a lot of      water for the oil to move though, Making it harder to get to the top).

That, spiceyokooko is why i am doing an Ebook!

[natterjak]

Nice explanation Chris. And this would fit with he observation that at the same time the oil separates to the top, there is a residue which forms at the bottom of the pan (the "sustenance" material no longer coated by oil). I often find that as the oil separates out of a base I can dredge up a residue from the bottom of the pan.

[emin-j]

This might answer a few questions,

Why Does Oil Float?
Make a home-made lava lamp by filling a jar two-thirds full of water and put in some food colouring. Add some cooking oil. The oil will float on top of the water. Shake some salt onto the oil

[PaulP]

If anyone is interested this is quite to the point:

https://stellaculinary.com/podcasts/video/what-is-an-emulsion-a-cooks-guide

As H4ppy-chris rightly says (in different words) the stability of the emulsion is determined by what he calls "sustenance" such as the non-water and non-oil components. And that does explain why lentils, cream, coconut block, flour etc. can determine how easily the oil separates, or not as the case may be.

I'm not sure what a micelle bond is though, maybe it is spelt wrong.

Cheers,

Paul

[Peripatetic Phil]

I'm not sure what a micelle bond is though, maybe it is spelt wrong.

If you promise not to tell those who already know, Paul, I'll let you in on a secret :

A micelle (pronounced /ma??s?l/ or /ma??si?l/, plural micelles, micella, or micellae) is an aggregate of surfactant molecules dispersed in a liquid colloid. A typical micelle in aqueous solution forms an aggregate with the hydrophilic "head" regions in contact with surrounding solvent, sequestering the hydrophobic single-tail regions in the micelle centre. This phase is caused by the packing behavior of single-tailed lipids in a bilayer. The difficulty filling all the volume of the interior of a bilayer, while accommodating the area per head group forced on the molecule by the hydration of the lipid head group, leads to the formation of the micelle. This type of micelle is known as a normal phase micelle (oil-in-water micelle). Inverse micelles have the head groups at the centre with the tails extending out (water-in-oil micelle). Micelles are approximately spherical in shape. Other phases, including shapes such as ellipsoids, cylinders, and bilayers, are also possible. The shape and size of a micelle is a function of the molecular geometry of its surfactant molecules and solution conditions such as surfactant concentration, temperature, pH, and ionic strength. The process of forming micelles is known as micellisation and forms part of the Phase behaviour of many lipids according to their polymorphism.

There, you always wanted to know that, didn't you ?!
** Phil.