Monday, December 15, 2014

Weekday Wonderings: Heating and holding? Figuring out the melting point? Pouring oil into water - how fast?

In this post, If you're new to lotion making, Heidi L asks: I can't mentally get past this one super basic concept... I understand the idea of heat and hold, I get the mechanics of double boilers. But how on earth do I control the temperatures of the water and oil phases? You list the minimum temp, but what is the max each phase can get before we start to see degradation of the beneficial properties of our ingredients? (I do of course realize that will vary based on exactly which ingredients I choose, but I'm hoping for a basic rule of thumb). I think you may have said 85 degrees somewhere, but does that apply to both phases? Then, I know the two phases need to be about the same temp when we combine them, but how close is close enough? I keep imagining having these 2 pots constantly on and off the heat, in and out of the water baths, stove on, stove off, as I frantically try to achieve and maintain a specific even temperature for 2 pots simultaneously. I can't help but imagine this horribly comical juggling act! Is there a trick to it, or is the reality of it just not as difficult as this frantic scenario I've built in my head?

It really isn't that difficult! If you're using a double boiler, the temperatures will increase slowly so you can monitor is quite easily. Just get yourself two nice candy thermometers and check on them from time to time.

Norm MacDonald had a bit where he explained why he always had little dogs. If they wanted to kill you, it would take them all night to try to bite through your jugular vein. When you woke up you could just shake them off with "Get off me, weiner dog!" I think of using a double boiler this way, although with less yelling about weiner dogs. (Okay, being honest here, slightly less yelling about weiner dogs. They are fun creatures!) The double boiler rises in temperature slowly enough that you can keep an eye on it for temperature. If it gets too hot, you just turn down the temperature on the element or the plug and it goes down.

This is why I don't suggest using microwave ovens. A few seconds too long and the metaphorical weiner dog has bitten through your vein and you're spewing blood everywhere! (Okay, you get the picture. No need for more gore, eh? This isn't the Walking Dead, after all!)

In all my years of making stuff, I've never had an oil get anywhere near a smoking temperature, let alone too hot to use in a lotion. I think the highest has been 80˚C. I wouldn't want anything to get over 85˚C because that's pretty high and can hurt you if you spill it. (I have no evidence I can point to for this number, but I remember seeing it somewhere and it makes sense to me. It's surprisingly hard to get your phases this high in a double boiler!)

As for how close the two phases should be - I would say no more than 10˚C apart, but I prefer 5˚C. So if you have your water phase at 75˚C, get your oil phase to 70˚C.

Another comment from Heidi L from the same post: One more question. I currently make an oil based body butter. Basic recipe is more or less: 50% butters, 25% coconut oil, 25% liquid oil. Any thoughts on how I'd determine the specific melting point for the finished product? I originally thought I could take the temp at which each ingredient liquifies and the % of the total solution and come up with a simple formula, but the liquid oil does not seem to have a temp at which it becomes solid available from reliable sources. When I plug in the figure I've gotten from the sources I have been able to find and then do the logical math, the calculation I come up with is clearly inaccurate. Thoughts?

There is no easy way to figure out the melting point of a product other than watching when it melts. We can't figure it out because of confounding factors like the amount of oleic acid in the product. Check out this post for more information on that!

In the same post, Jay Sy asks: When you are adding the water phase to the oil phase, are you blending the oil phase and slowly pouring the water phase into the mix? Or are you literally just pouring the water phase into the oil phase, inserting the stick blender, and then blending away?

I just pour the oil phase into the water phase and start mixing then. I don't worry about how fast or slow I'm adding the oil - I just pour and then mix. Part of that is so I can see the awesome power of emulsification in action; the other part is that I am very klutzy and if I try to do more than one thing at a time, I will make a horrible mess. Mixing and pouring will not work for me!

Join me tomorrow when I share the first of some of my exciting experiments from the workshop with you! Woo!


Birgit said...

You forgot to answer the part about how close in temperature should the oil and water phase be for the lotion to happen. Was it 10 degrees (Celsius)?

Susan Barclay-Nichols said...

Hi Birgit! It was awesome to meet you on Saturday! Have you tried what we made yet?

Thanks for catching that. You can do 10˚C, but 5˚C is better.

Jay Sy said...

You Rock Susan! Thanks for answering my question. I can't wait to try it again this weekend. :)

Birgit said...

Susan, it was lovely meeting you, too. We had such good time.
I have tried all the products, here's how I feel. I love all the wash-off products, they are all great. The serum and eye gel are nice as well. The moisturizer is a tad too powdery for my taste, next time I will definitely add some oil (squalane, fractionated coconut our something similar), but in general I like it. The toner is super sticky, and the extracts (I used 0,3 grams of either instead of recommended 0,5) never really dissolved despite of plenty of heating and shaking. I even added more rose water in case I had reached the point where no more could dissolve. I use it under serum or moisturizer and it's fine, just looks really ugly with all the extracts clumped up swimming around. I may just strain it before the pump gets clogged.
Thanks for the super fun class and a great blog!

melian1 said...

i make my stuff in my kitchen, and i found using double boilers cumbersome and used a lot of my elbow room (cramped quarters). so i started using my oven (not microwave oven, a regular one). i set it at its lowest (mine is 170F tho some ovens will go as low as 150F) and put my water and oil phases side by side in there. i set my timer for 30 minutes and use that time to have some tea or clean up some of the mess i've made, or get my jars or bottles ready, etc. i don't have to worry about temp or watching it, and both phases are exactly the same temp when i get them out. of course, i add stuff to the water phase after i weigh it out, so i do have to watch that temp changing, but pretty much it makes it all easier. it works for me also because it is already held when i weigh it out so i never have to re-weigh and account for water loss from the holding time.

my own personal experience is that if i get further apart than about 10F in temperature between my phases when i mix, trouble can happen. if i'm much further, emulsification usually fails. i know there are folks who say they never take the temps and never have failures, but ime i can expect a screw-up if i go much over about 10F apart in the two phases.

melian1 said...

i remember a post on the Dish board from Liz about figuring melting points of lotion bars and so on. i put it in my notes at the time, and i quote it here, in case it helps:
"The formula is

Fa + F'b / a+b = MP of total mixture

Where F & F' are individual melting points of 2 ingredients and a + b are the quantities used


4 parts paraffin with MP 55C
2 parts paraffin with MP 49C

4 x 55 + 2 x 49/ 4 + 2 = 220 + 98/6 = 53C

The total mixture will have a MP of 53C

So of course you can use this formula for more than 2 ingredients."

Birgit said...

Melian, that looks good. How about liquid oils, what would be their melting point?

Ecochi said...

I use the heat and hold method as it helps with the emulsification process as well. I don't usedoubkw boilers, just straight on yo my glass oven top. Easy to maintain temp. My question is the oxygen/bubbles that can arise in lotions. With added Dimethicone and glycerine to the product, this helps. But I'm starting to think it's a heat issue, not a blending issue. So I trialed one batch after emulsification and waited till very cool then poured, but still retained small bubbles. I burp the blender etc. I'm wondering if it's the heat and hold phase. I.e mixing these two re. Oil and water phase when a much lower cooler temp, rather than the one it's been sitting at for 20mins. I'm going to test this theory this week. Would be great if anyone else is trying to work this one out and has problem with small bubbles ion top of lotion.

Melanie said...

Will emulsification always be immediate? I made your "pirate" beard conditioner last night and at first when i just poured it and and stirred it looked emulsified though yellowish. Then oil drops started forming. It wasn't until i blended it with the hand mixer for 5 minutes that it looked really white and seemed stable. Is that normal?

Birgit said...

And I understand all oils have melting points but when I introduce oils with melting points below 0C, like olive oil, the math somehow goes off, and the melting point ends up being around 10C, which is clearly wrong.

Susan Barclay-Nichols said...

Hi Birgit! As for the moisturizer, the powderiness comes from the BTMS-50. You can try adding oils to it or try making it with Polawax instead and see how you like it. Those powdered extracts are a bit of a pain. Sometimes they dissolve with no issue, other times there's still a bit of powder at the bottom no matter what you do!

What you mention is why it's hard to figure out a melting point because the liquid oils can mess it up!

Hi melian! Thanks for the formula! And for the oven suggestion! It's a great option for people who have workspaces in the kitchen!

Hi Ecochi! How are you mixing your products? And what emulsifier are you using? I use a hand mixer after heating and holding and haven't found there are tons of bubbles in any of my lotions. If you could post a recipe, that would help!

Hi Melanie! As usual, a great question. I'm answering it in Saturday, December 20th's Weekend Wonderings. The short answer is that it isn't always immediate.

AlannaBanana said...

I am having a problem where the oil phase gets hotter than the water phase. I have both identical glass cups in the same water bath. I'm wondering if, after 20 minutes, should i take the oil phase out and let it cool to within 5 degrees of the water phase? The last batch of lotion was an epic fail, so i'm trying to figure out what went wrong, and i'm wondering if the difference in temp is what made it separate...
Thanks everyone!

Susan Barclay-Nichols said...

Hi AlannaBanana! I'm not sure why your lotion failed. If you want to post the exact recipe in percentages and your exact process, we could try to troubleshoot it. As for keeping things at the same temperature, if you get them within 5˚C of each other, that's the ideal, but you can go a little higher and not suffer too many issues. Your oil phase will get hotter than the water phase thanks to its specific heat capacity being lower.

Wendy Gaechter said...

I love Melian's idea of heating and holding in the oven! I am a little confused about not worrying about water loss using this method. Can anyone explain? I will try this today!