Now that I have been experimenting with formulations for about eight years, I am beginning to question some basic things that I was taught at the outset. I will try to keep my inquiry brief, and keep in mind that this applies to all oil-in-water emulsions and water-in-oil emulsions, as this is an issue of chemistry and physics.
Here is my question: I am wonder how much (if at all) does it really matter whether you pour the oil phase into the water phase, or the water into the oil phase, while creating an emulsion.
In this case, the following can be assumed:
1) Both phases were measured separately and heated up in their own separate vessels, up to the necessary temperature (i.e. - highest melting point of the ingredient with the highest temperature requirement for liquifying).
2) After pouring one phase into the other, the high-shear mixing begins within seconds of this action.
NOTE: On this issue, I have received contradictory responses from many other sources (other formulators and lab technicians). I am always reluctant to conclude someone is wrong on any issue (unless it's a clearly objective fact, like a mathematical calculation that doesn't add up). I have found in most cases the differences are a mix of facts and opinions, and they are simply talking about different things from different perspectives, and may have not realized it.
More specifically, my question involves the following concepts:
1) The emulsifying agents are really what determines whether you have an oil-in-water, or water-in-oil emulsion . . . correct? If your emulsifiers have an HLB value that is below 6/7, then you are pulling water in the lipids (the continuous phase), right? And if the emulsifiers have an HLB value that is higher than 9/10, you are pulling lipids into the water phase (continuous phase), right? This is assuming that you have an adequate amount of emulifying agents to get the job, and create a stable emulsion.
2) So whether you begin by adding one phase or the alternative into the other vessel, they both end up in the same place, and as long as the heat is higher than needed to keep everything melted, then it's really the high-shear mixing (the heat and energy) that form the emulsion . . . correct?
3) Without getting to complicated, some people have commented that this may create an issue with developing an emulsion that is actually closer to a "WATER-IN-OIL-IN-WATER" (W/O/W) which is uncommon. Don't know if anyone here has ever tried to create an w/o/w emulsion, but that may be a separate discussion if it's not relevant to this specific topic.
Hopefully someone will have an articulate scientific explanation for this inquiry.