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Tricks to minimize necessary equipment
Hi all,
I am a complete beginning starting out at home making emulsions where I need to heat an oil phase and an aqueous phase before mixing them together. From reading a few formulas, it seems this would require two hotplates with two overhead mixers working in parallel: one for the oil phase, one for the aqueous phase. Am I missing something? Is there a creative (or blatantly obvious, haha) way to do this without needing two batch setups? Of course, the concern here is cost minimization.
How do you do your classic hot mix emulsion? Do you continuously mix while heating?
Thanks!
Matt -
6 Replies
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@matt719: You don’t need to get so complicated to begin. You will need a hotplate for melting solid lipids. You don’t need to mix anything on the hotplate and in fact to do that isn’t safe.
You should get a large microwave oven - the largest you can find, and it is vertical height inside that I am referring to. This makes a great heater of anything that contains water. Not only that, but the microwaves also sterilise the beaker so you get a really sterile result.So melt the lipids on the hotplate and get them to the required temperature and bring up the polar materials to the required temperature and then blend using a stick blender, again the biggest damn one you can find. -
@Belassi. Thanks for your reply. Good point, that does seem like a better ticket for at home. However, I am actually going to be moving into a lab space and I am looking to do professional-caliber research (I am a chemical engineer). With that in mind, what do you do as professional cosmetic chemist? I was imagining needing two hotplates, two mixers, and possibly a homogenizer. After your comment, it sounds like I’d only need one mixer. Is that right?
Extra credit question: how much of the time are cosmetic chemists working in a fume hood?
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If you are at home you really don’t need a lot of equipment to get started. There are few options for heating but one of the best for beginners is probably a double boiler setup. I have in the past just used a saucepan partially filled with water heated on my cook top with my stainless steel bowl sitting on top. I personally don’t like microwaves because of the tendency to overheat or not evenly heat the contents.
There is no need to constantly stir both phases when heating them just give them a stir periodically to ensure that they are heated evenly.A stick blender is great to mix the two phases together.
Check out swiftcraftmonkey’s blog for lots of useful information.
http://swiftcraftymonkey.blogspot.com.au/p/newbie-links.html -
I would recommend that your set-up include:
(1) Microwave (I’m with Belassi on that one … I use the microwave to get my water phase (and oil phase for that matter) close to final temperature. If you do some simple experimentation, you will determine the right power setting and time that gets a particular volume of a particular liquid up to the desired temperature. Undershoot just a tad and then bring it up to your target temperature in a water bath (double boiler) … I find this saves a considerable amount of time.(2) Water bath or double boiler … preferrably large enough to hold two beakers side by side(3) 1 10″ X 10″ hot plate with magnetic stirrer (and stir bars)(4) 1 10″ X 10″ magnetic stirrer(5) 1 homogenizer(6) 1 overhead stirrer(7) 1 digital scale (500 to 1000 gram capacity, accurate to at least 0.1 gram) and calibration kit.(
1 pH meter(9) A good set of beakers of various sizes(10) a viscometer(11) If you plan on doing your own stability testing, your going to need an incubator or oven that heats to 50C. You’ll also need a freezer (or access to one) for freeze/thaw cycle testing.When you’re making an emulsion, no, you don’t necessarily need to stir continuously through the entire cool down period. Generally, you slowly add the oil phase to the water phase while homogenizing for 3 to 5 minutes, let it cool down a bit, homogenize some more … let it cool down a bit. When you reach the “set” temperature, you’ll notice that your emulsion does not separate and begins thickening to a homogeneous consistency. But, you certainly can homogenize the entire time if you like. -
Get a good scale - I paid $350 for a 2Kg scale in 0.1g increments - and also get one of those cheap Chinese jewelers scales, 0-100g in 0.01g increments, for measuring small amounts at the 0.1% end of the ingredients.
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If you’re doing this professionally, you will want to come as close as you can to simulating the processing equipment and conditions at the factory that will be making your products. Most private label companies will be willing to give prospective customers a tour of their processing floor - I strongly recomend at least one field trip.
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