Tuesday, October 4, 2011

Creating products: Heating and holding

Let's start by defining what it means to "heat and hold"...
Heating and holding means heating the heated oil phase and heated water phase separately in two heat-resistant containers in indirect heat (like a double boiler) for 20 minutes at 70˚C or 158˚F. The 20 minutes starts when the ingredients reach the required temperature. 


What do we heat and hold? We heat and hold the heated oil phase and heated water phases of lotions, and we heat and hold the water phases of things like shampoos, body washes, bubble baths, and cleansers. We don't need to heat and hold the oil phase of something like a lotion bar if we are making anhydrous or non-water containing products. But if we have a water phase, that product must be heated and held.

How do I heat and hold? (Click here for the original post!)
Weigh all your oil phase ingredients into a heat resistant container. Weigh all your water phase ingredients into a heat resistant container. Heat your double boiler up - I tend to boil up the water, then reduce the heat when I put my containers into the double boiler. Watch the temperature on your two containers. When they reach 70˚C or 158˚F, that's when the heating and holding starts. Get yourself a timer, set it for 20 minutes, and when the buzzer goes off, combine the two phases and mix!

The key to the heating and holding is the holding part. Heating things in a microwave enough to melt or boiling water is NOT enough to achieve the goals of heating and holding.

Why should I heat and hold? (Click here for the original post!)
1. Killing the nasties in our ingredients and/or water. When we heat the water and hold it, we will kill a lot of the gross little things that can get into our products.

2. Helping with emulsification. This one's a little more complicated.
Click here if you want to learn more about micelles before reading this post.
Click here if you want to see this post in full because it's really quite interesting! 

When we reach the critical micelle temperature or Krafft temperature - suggested as 70˚C to 80˚C for Polawax - we will see our micelles form properly, which means the emulsification has worked and we will get a nice lotion that shouldn't separate. If our oil phase is at 70˚C and our water phase is at 100˚C (boiling point of water in Celsius), then they may not come together properly. If our oil phase is lower than 70˚C, we might see a very unstable emulsion. When we heat something, we generally increase its solubility. Non-ionic emulsifiers (like Polawax or e-wax NF) are water soluble at low temperatures, oil soluble at higher temperatures. To form a good emulsion, we want it to be at the higher temperatures.

I realize there are times that you have made a lotion without heating and holding for the full 20 minutes, and I realize there are some very knowledgeable people out there who swear by heating the ingredients up in a microwave, but having something work once or twice doesn't mean it works all the time.

Why do we need two separate containers? We're going to mix it all together eventually and/or I don't have enough space to heat two containers in my double boiler? (Click here for original post.) 
Emulsification comes in three ways - heat emulsification, chemical emulsification, and mechanical emulsification. When you get an emulsion that works on day one but fails on day ten, it could be that you mixed it well enough to get a mechanical emulsion, but messed up on the chemical emulsification (not enough emulsifier or the wrong emulsifier) or the heat emulsification (not hot enough, phases not at the same temperature). It makes sense to heat all the ingredients in the same container - we ensure both phases are at the same temperature when we remove it from the heat to mix it - but it can make us think we have an emulsion when we don't. The phases need to be held separately so when they meet after the heat and hold, they have a chance to create an emulsion. If we have been holding them together, they could be doing the emulsification thing at much lower temperatures, which we know is unstable!

Here's a great quote from the legendary LabRat:
When you mix your emulsifiers, waxes, oils, water and other additives all together in one pot, you are making your emulsifier(s) work harder. That's not bad and it's not good but it's probably very inefficient.  


What if I can't heat and hold? 
As I mentioned in this post the other day, it's not expensive to visit your local thrift store and pick up an electric fondue pot or crock pot to help you heat and hold. Or you can create a double boiler on your stove top.

If you really can't heat and hold, then perhaps lotion making isn't for you. I know that must sound harsh, but I hope I've convinced you that it is essential to make safe, stable products. You can make anhydrous products (things that don't contain water) like lotion bars or scrubs because we don't generally heat and hold them, or you can make things like bath salts and bath bombs, but heating and holding is essential for things that contain water.

If you have any questions, please share them in the comments space for this post because this is a topic about which everyone seems to have questions! Join me tomorrow for more formulating fun!

17 comments:

Always.Looking.4.1.More said...

Hi everyone. Susan, this is so much fun! Thanks for your definition of "heat and hold". People like me need you to be specific like that. I'm glad I read this just minutes before I was going to make another anhydrous formula. I thought ALL formulations have to be heated and held. So I have a few questions.

1. Don't "nasties" grow on oils? I've always thought they're as susceptible to germs as water is. (If I sneeze or cough over two open bowls, one containing water and the other containing mango butter, aren't they both going to be contaminated?)

2. I thought we are to combine the two heated phases while they are both at the 70C point (after 20 mins. of heating), THEN let them go through the holding/cool down phase together as one. This is what I've been doing, but it seems that I've been wrong. Have I been having success that might fall apart one day using this method? Since it's been working I thought I was doing it right. Oops!
This is the part that confused me:
"The phases need to be held separately so when they meet after the heat and hold, they have a chance to create and emulsion. If we have been holding them together, they could be doing the emulsification thing at much lower temperatures, which we know is unstable!"

Thanks!
:-)

Susan Barclay-Nichols said...

Hi Always! There are some things that can grow in oils, but they are few and far between, so we don't worry so much. If you cough or sneeze on your oils, you might have a problem, but it's easy to avoid that - don't cough or sneeze on them! I generally heat my oils and butters until melted, then I use them in whatever anhydrous product I'm making. There's no bad in heating them for longer - if I'm working on something else in the workshop and I don't have time to get to that scrub bar melting in the double boiler, I'll leave it for longer - but it isn't necessary.

No, you're doing it right! Combine the phases after heating, mix well, then allow them to cool down to 45˚C so you can add the rest of the goodies. This information is about heating and holding both phases in the same container, which some people like to do!

melian1 said...

you mentioned to weigh the water and put into the container for heating and holding, but if you don't also have some extra water you heat and hold and re-measure before you combine, you don't account for evaporation, which will throw the recipe off.

why do you recommend heating and holding using indirect heat rather than direct, or oven holding once it's at temp?

Cordy said...

Hi, Susan!

When heating and holding, do you take the temperature of each phase at intervals, or do you leave a thermometer in each container, or some other option?

I'm about to try making my first ever lotion, btw. Exciting!

~Cordy

Leman said...
This comment has been removed by the author.
Leman said...

Hi Susan,

Great post as always! and thanks for being so specific. This is not quite relevant but I thought I'll ask since you mention that we don't heat and hold anhydrous or non-water products.

1) When I make balms (non water) with shea butter it forms grainy bits after few days. Some people say when shea butter is melted it should be heated and held for 20mins at 70˚C temperature to prevent graineness and others say the faster you cool off the shea butter mixture by putting it into the freezer for few mins the less it will go grainy. And some say just to soften shea butter not melt. What's your experience with shea butter in anhydrous products?

2) Similar to Corby, I always wonder whether I should be taking the temperature by not touching the tip of the thermometer to the base of the container. Thinking that the base of the container is hotter than the ingredients inside and it would not reflect a true measurement! What's the best way to measure?

3) I have been heating and holding in two seperate double boilers. Maybe that's way my lotion failed on few occasions by not having them at the same temperature. I don't have a fondue or crock pot but maybe I can use a large saute pan to put the two containers in.

zaczarowany pierniczek said...

Hi!
Such a post is a really great idea. I like to watch videos about making comsmetics on YT and I've noticed that a lot of people have no idea how to do that properly and they see nothing wrong in misinforming others, e.g. this one (http://www.youtube.com/watch?v=lylREtvDBHg) - no proper emulsifaction, no correct information about time and temperature of emulsifaction, no real preservative and no information about keeping it in a fridge. After reading your posts about creating products I'm kind of scared what this women and others like her do and share with youtubers. That's awfully irresponsible!

Natalie said...

Once again, great post! Thank you Susan.

I'll be trying my first lotion next week so I'll make sure to heat and hold my phases!

Looking forward to reading your next post :)

Dana Walt said...

I am new to lotion making and I have a question or two about heating and holding. I understand the whys of it, but how do you hold the temp? If it starts getting to hot do you pull it out? (That may be a real dumb question). I am probably wrong, but I was thinking if you did that then it would cause such a sudden drop that wouldn't be good. In a crockpot what is the best way to do it? Thanks a bunch! I have learned alot from here!

Susan Barclay-Nichols said...

Hi Dana. I've addressed your questions in these posts - creating products: heating & holding and what if you go over 70˚C while heating and holding. The short answers are create a double boiler and it's okay if they go over 70˚C as long as both phases are around the same temperature when you mix them!

Melanie said...

Hi Susan! I'm very interested on this but still confused. If I'm making a hand lotion with shea butter, almond oil and beeswax should I put in a separate container the shea butter and in an other one the other ingredients and both hear them at 70. And hold the shea butter for 20 minutes and then mix all ingredients at the same temperature? After this should I let it cool down by it self? Or in the freezer? Cause I want to use the mixer to get a good consistency...

Susan Barclay-Nichols said...

Hi Melanie. Could you please post the recipe you're using because I don't think you're making a lotion as you aren't using water. It sounds like you're making a balm or a lotion bar or another anhydrous product. So you don't need to heat and hold the ingredients - just heat until melted. Then let it cool down in the container of choice. You can put it in the fridge or the freezer.

Laurie said...

With regard to heating and holding the water phase. If you have other ingredients in the distilled water, such as rosewater, for instance, how do you account for any of it evaporating? I understand adding extra water, and then re-measuring after heating is complete, but what about other additives in the water?

Ryan Pusztai said...

Do you have to heat & hold with shampoo when using surfactants Cocomidopropyl Betaine & Decyl Polyglucose surfactant?

My recipe did not thicken up correctly & has a slimy snot feeling to it haha. I found this recipe on this forum Here is what I used:

20% Cocomidopropyl Betaine
21% Decyl Polyglucose
20% Aloe Vera
28.1% water
4% glycerin
2% Panthenol
0.5% liquid Germall Plus
1% EOs
0.4% Citric Acid

Any help on this would be greatly appreciated!

Ryan Pusztai said...

This is a body wash recipe I meant haha not shampoo

Susan Barclay-Nichols said...

Hi Ryan. I recommend you ask the writer of the recipe for assistance as they should be able to explain better all the ingredients and process. Out of curiosity, what is your final pH?

Jenni Raincloud said...

Hi Susan! I always heat and hold my creams but I have such a hard time with holding the temp around 158F! My mixtures always tend to rise way above that, like to 170F. I literally stand there and fiddle with the stove top temps trying to keep them from getting too hot. How do you set a timer and walk away? Also, do you know what temp. oils start to lose their properties at? That's my fear with getting them too hot.