Sunday, March 24, 2013

Weekend Wonderings: Compensation for evaporation, Polawax as a possible replacement for beeswax, and using Epsom salts in bath bombs

Have something you want to ask? Visit the Weekend Wondering comment post and ask away! 

In an e-mail, Brittany asks: I've struggled with the heating of the water phase for a while now. You suggest to heat the water phase for 20 minutes, but to add more than the needed amount to account for evaporation. I find that after 20 minutes, most of my water is completely gone so I'm stuck with having to add more and reheat. This continues until I just end up adding the unsterilized amount I need to make up for evaporation. Any tricks to make this easier or am I just missing something?

I answer this question in great detail in this post - question: compensation for evaporation - but the basic idea is to heat and hold some water in a separate container and add it to the product after you remove the heated water phase from the double boiler. I measure out my heated water phase, weigh the entire container before heating, and add back what I lost at the end of the process. You can boil up some water and let it cool down to 70˚C to 80˚C as well. Please use distilled water for this process.

You don't want to add non-heated water to the heated water phase because it will mess with temperatures, which can lead to a serious lotion fail.

If you are losing all your water, something is happening that isn't quite right. Even making a 100 gram batch of lotion (say you have 60 grams of water) shouldn't result in losing all the water. Those Pyrex type jugs I have above will lose a lot more water than one that is partially covered - see this post for more information - so you might want to reconsider using another type of container. Perhaps putting a piece of plastic over the container to stop such huge amounts of evaporation would help?

As a quick note, I don't remember suggesting adding more water to the water phase at the start of the heating process. My suggestion has always been to add more similar temperature water at the end of the process. If you find a post where I suggest adding more, please let me know so I can correct that! 

Related posts:
Surface area and evaporation

In this post on emulsifying systems, Sera asks: I was wondering if you can use Polawax for a lip balm, instead of beeswax? I have Polawax at home but no beeswax and I really want to make a moisturizing lip balm. 

No. Emulsifying wax is not a wax - it is an emulsifier. Beeswax is what we would consider to be a traditional type of wax. The two are NOT interchangeable in any way. Adding it to a lip balm will make it taste weird, and it won't have any of the stiffness we come to associate with a lip balm.

Waxes are used to stiffen our products without making them too brittle, increase the melting temperature, and add structure to a product. Emulsifying waxes are used to bring water and oil together in a product to create emulsions. They are not even remotely close to each other in function. You can find beeswax in small white or yellow pellets, but this appearance is a coincidence.

Part of the confusion is the name - beeswax and e-wax do sound similar - but if you want to see if one can be used in place of the other, ask your self about the function of the ingredient. If I want to create a lotion, I need an emulsifier, therefore I should choose e-wax. If I want to create a lotion bar that is stiff and only melts on contact with my skin, then I want to use beeswax. We can use beeswax in our lotions to add a bit of drag and tenacity, but beeswax isn't an emulsifier.

Great question, Sera! Thanks for sharing your thoughts!

Related posts:
Question: Mixing oils and water
How do some people manage to get water soluble things into anhydrous products?

In this post on bath bombs, Anonymous comments: Epsom salts?

I think this is in relation to the idea that one can put Epsom salts into a bath bomb. I haven't tried this. Have you? What were your results? I'd love to know what you thought of making and using a product like this!

Definitely don't put Dead Sea Salts into a bath bomb - they are very hygroscopic and will set off the fizz in your products while they are sitting waiting to be packaged!


Ged said...

Hi Brittany (and Susan)

You can also keep some extra heated water in a vacuum flask or jug. I usually boil some ahead of time and let it cool down a little then keep in the vacuum jug for adding to adjust for evaporation. That said, covering the jug/bowl or whatever you're heating the water in should lead to less evaporation

Little Bird said...

Hi Susan. I use 1 part epsom salts, 1 part citric acid and 2 parts baking soda. I love the feeling of the water and I think that it actually fizzes a little longer.

melian1 said...

i never try to weigh out my water for my batch before heating and holding except in the most general fashion, being sure i have more than enough. i put that amount into a glass coffee pot (thrift store find, tested to be sure the plastic top will withstand temps of 175F), and another amount (a couple of hundred grams or less, depending on the size of the batch i'm making). i heat both to temp, pop them into a 170F oven and set my timer. when the time is up and i'm ready, i weigh out the correct amount of water at that time. if my original amount is insufficient, i supplement with the side amount. with the plastic top covering the coffeepot, i rarely ever evaporate away very much. i figure what little over i have is a small investment to be sure i have enough water, heated and held, and all at the same temp.

i also heat and hold my oil phase right beside the water (all on a big cookie sheet) so they are exactly the same.

an advantage of this is that if i'm not quite ready to go when the exact 20 minutes is up, the oven will hold it at the right temp for however long it takes me, and i never have to worry if it is too hot or not hot enough. and with the side amount of water right there, i am sure to have enough of the water when i weigh it for the batch.

Leslie said...

Melian 1 - I have never thought of using my oven for heating and holding. It seems that it would take a lot of the temperature guess work out.

Does anyone else use this procedure?


Ged said...

The oven sounds a good idea (I like the idea of heating the oils there too) but sadly a: the oven is in the kitchen not my workshop and b: it never gets cleaned!

it occurs to me though that I'm replacing my microwave so I could get a combination one. Hmm, thanks melian, might investigate that ...

Row said...

I heat and hold in the oven. I use stainless expresso pots which I cover with tin foil. The tin foil catches the steam and it drips back into the pot containing the water phase. I've never been short by more than 1/2 a gram or so. If it's for myself I don't bother topping it off. I also use one of those laser thermometers that I can't live without anymore. It's just too easy and very accurate.
Thank you for your blog, Susan

Anonymous said...

Hi Swift,
thank you for your explanation.Indeed the Polawax has wax in the name and it is a bit confusing.I actually needed an emulsifier in my lip balm because I wanted to incorporate aloe vera in it.Anyways I ended up making one with- aloe vera,lanolin,cocoa butter,shea butter whipped with oils,castor oil,honey(for the taste but didn't help much because I used a small amount)and vit.E.It turned out ok,bit grainy(i think it's because of the shea)but it was ok.
Ám going to share lots of thoughts (maybe you shouldn't have encouraged me lol)because am really enjoying making all kinds of products and learning the function and reaction of the ingredients.
I also have trouble with the water evaporating so I hit more water than required and it compensates the loss.The oven is a great idea.

Susan Barclay-Nichols said...

Thanks for the great conversation!

And Sera - where are the questions? I'm waiting! :-)