Tuesday, June 7, 2016

Weekday Wonderings: Using potassium sorbate alone isn't a good idea! How to add things to the cool down phase? Can you fully replace the water in a lotion with something else?

I've noticed a lot of people using potassium sorbate and sorbic acid as the only preservatives in a product. Neither of these are what we call broad spectrum preservatives, ones that will take care of bacteria, fungus, yeast, and mold, so you have to pair them with another one. Neither of these are good with bacteria, so pairing them with phenoxyethanol or Optiphen or another effective bacteria beater is a great idea!

In this post, How do you know when to add an ingredient?, Tiffany asks: My first question is about the cool down phase. The stuff you add in this phase do you just add it when the temperature is right or do you dilute it with water or oil first then set it aside? Then add it when the lotion has cooled? I really may be nuking this but I can't seem to find anything on the subject?

Second question. Can you fully replace the water in a lotion with aloe vera juice or a hydrosol? I have been trying to find an answer for this but have come up empty handed.

Yes, you just add the cool down phase into the container when the temperature reaches 45˚C. You don't need to mess around with it. Just weigh it like you would the other ingredients directly into the container. Something that needs to be diluted, like a powdered extract or preservative, can be mixed with a titch of warm water to get the process going, but you could just put it into the container and let the warm water dilute it.

Related posts:
Newbie section
Creating products: The cool down phase
How do you know when to add things?
Learning to formulate: The cool down phase

As for your second question, no, you don't want to replace all the water with something else. Water is an important part of our lotions - it's not just filler. Plus all those lovely things you want to use instead of water contain electrolytes, which can throw off the emulsion or the preservative. Better to use no more than 10% aloe vera or 10% hydrosol and add distilled water for the rest.

Related posts:
Water isn't just filler


VirgĂ­nia Fernandes said...

Hi, Susan!

I'm very pleased to come across your blog, which I discovered by searching for a duplicate for the Kiehls Midnight Recovery Oil. I am a chemical engineer and I'm from Brazil, so greetings from the south! :)
Just like you, I'm very passionate about cosmetic chemistry - however, I hate the manufacturing process, so I always have someone make the recipes for me :P. But the thing is I absolutely adore to learn more and more about this beautiful chemistry branch and that's why I am so mesmerized by the great content you upload. In a nutshell, I'd just like to say congratulations for the good work and know that what you're doing is highly appreciated.

That would be all for now. Hope you have a good one! :)

ingenting said...

Hi Susan:)

In this post you write about pairing potassium sorbate with another preservative...
I was wondering (not just for this case, but in general), when pairing preservatives, how much should you add of each? Would you need to adjust the recommended usage rate in some way? Or can you use each preservative at their own recommended usage rate?

E.g. (I'm totally making this combo up, btw), if you want to combine LGP with Germaben II, would you use 0.5% LGP and 1% Germaben II, for a total of 1.5% preservative... or would you dial it down to, say, 0.3% LGP and 0.5% Germaben II?

And...one request...
I was wondering if one day you could do a post on recommended books to teach yourself diy cosmetics, or the books that have helped you get to here ( chemistry books included:) ).

In any case, thanks again!!

Susan Barclay-Nichols said...

Hi Virginia! Wow, thank you for your kind words. You don't like the formulating! I love writing up recipes, then getting into my workshop to see if they work! Maybe you're not making the recipes you love? Maybe you need to branch out into hair care, lotions, body washes, and more?

Hi ingenting! I've written up my answers to your questions in today's Weekday Wonderings

LoveSmoothJazz said...

Hi Susan,

Just like Virginia I am so happy to come across your site. My name is also Susan and I am from hot & sunny Arizona. I have long had an interest in skin care having suffered with many issues as a teen. In the past I spent quite a bit of time reading up to learn how to formulate something on my own. I purchased some basic supplies but sadly, life got in the way and I never pursued this. However, I have recently rediscovered my interest in this (and Korean SkinCare) and am back on a journey to learn as much as I can before I attempt something (simple). I have no background in formulating but hopefully my crafty, detail oriented, inquisitive (and sometimes intuitive) nature will help when I am ready to try my first formula. Thank you for all the information you have put out here.