Monday, October 3, 2011

Question: What if you go over 70˚C when heating & holding?

In this post on heating and holding, Nedeia asks: What could go wrong if you heat your ingredients at more than 70 degrees, say 80? I do not have a crock pot , and the best way I have found to get the 2 phases at the right temp at the same time, is to place them into a bowl of hot water. they get to 70 degrees or a bit more, but I cannt hold at 70 for 20 minutes, the water will cool down eventually, and constantly heating it from time to time is not an option for someone that also needs to watch a kid :)

Using a 0.5-1% Optiphen would keep the lotion mold and germ free for a period of time, so... could I skip the hold period, especially because I cannot control the temperature without the risk of "burning" the oils?

You have two questions here, so let's take a look at question number one: What could go wrong if you go over 70˚C to 80˚C when heating and holding?

The short answer is that going to 80˚C isn't a bad thing when heating and holding, but I wouldn't want to go over. The long answer is this...

For some strange reason, we see our oils as remarkably fragile when it comes to heating and holding. This is the number one reason people say they don't want to heat and hold - they're worried about losing the goodness in the oils, speeding up oxidation, or having them burn. Oils can handle a lot more heat than we think!

All oils have a smoke point and we don't want heat our oils above that point, but they really aren't that fragile! For instance, camellia seed oil has a smoke point of 485˚F or 251.7˚C, grapeseed has a smoke point of 420˚F or 216 ˚C, and even flax seed can handle 225˚F or 107˚C (one of the lowest smoke points). As you can see, these oils can handle temperatures far higher than our heating and hold temperatures. (Click here for a handy dandy chart on smoke points from Wikipedia!) So leaving them at 70˚C/158˚F to 80˚C/176˚F for 20 minutes won't burn them or ruin the awesome power of their fatty acids!

Having said this, just because the oils can handle a little bit more heat doesn't mean we should heat our other ingredients up to higher levels! I wouldn't want to go over 80˚C for things like my water phase - more evaporation isn't a good thing - and I wouldn't want to expose my emulsifiers to something more than 80˚C. But it is safe, for the most part, to go over 70˚C when you're heating and holding. (Yes, there are some ingredients that we don't want to heat and hold and some that don't want to be over 70˚C, but I can't go into every ingredient in this post!)

Just make sure your two phases are around the same temperature when you add them. If your water phase is at 60˚C and your oil phase at 80˚C (or vice versa), this can lead to epic lotion failure. If you can get them within a few degrees of each other, all should be good!

There are a few different reasons to heat and hold our heated water phase and heated oil phase. The main two are to eliminate possible contamination and to get our ingredients to the phase inversion temperature so we can have an awesome and stable emulsion. (Click here for a lengthy post on heating and holding and click for another one on heating and holding the phases separately. Click here for a post on how and why lotions fail.)

I don't consider heating and holding optional. It is necessary to ensure we get a safe, stable lotion. If you don't have a crock pot, get something like one at a thrift store. (I could get you at least three crock pots at my local Sally Ann's for $10 each!) You can create a double boiler using two pots on a stove, but if you've got a little one running about, that's probably not an option either.

As for the second question - can you skip the hold period? - no. Yes, your preservative will work to stave off contamination, but you need to heat and hold the lotion to ensure you start with lower levels of contamination. We are never going to get rid of the bacteria, yeast, and other nasties entirely because they're everywhere in the environment, but heating and holding can substantially reduce those nasties! Why start off the shelf life of your lotion with ickiness when it's so easily avoided? (Although, having said this, Optiphen is not considered a broad spectrum preservative, so there's always the chance of mould!) As well, don't you want a well emulsified lotion?

If you really want to avoid heating and holding, you could consider an emulsifier like Sucragel AOF. I find this product limited in that I can't make a thick lotion and it feels sticky, but it can be used without heating and holding. I have no idea how much it costs or where to get it - Susan from Saffire Blue sent me samples of it for posts for her blog, but I don't see it in her shop yet - but if you really can't find the time or equipment to heat and hold, this might be an option! (Click here for the video on how to use it!)

To summarize this post in a few sentences: You can go higher than the heating and holding temperature of 70˚C/158˚F without ruining your oils, and heating and holding is an essential part of lotion making to reduce the risk of contamination and to ensure we make a good lotion.

Join me tomorrow for more fun formulating!


Kathy said...

Susan - If a butter, like shea or mango, is part of the oil phase, will heating it over 70 make the final product grainy? What does cause the grainy-ness?

Nedeia said...

Susan - thanks for the post! I am now wiser :))

I have recently bought Microkill cos, so I will be using this after empying my bottle of optiphen. Or could I use both of them in a product? (I guess I should only use microkill cos , but I am wondering ,I hate to throw away ingredients!)

Nedeia said...

about crock pots and my country.... this is not at all a familiar product on our market, I have been looking for one since ... well, don't start me! I think I'll go to , but I would like to know : any crock pot will do? do I have to look for something specific when buying it? I mean besides the obvious - it should fir my 2 beakers and be able to use a wide temp range.

Nedeia said...

Frustration: are there crock pots where you can set your own temp?! All I see are crock pots with 3 settings: log, high and another one ....

Readers in europe, help :-)

Bajan Lily said...

Hi Nedeia,
I am also in Europe and the only crock pots I have been able to find are ones which say: 'high, low and warm' too.

I just use a double boiler now as it seems to reach the desired temperature quickly and I can keep it there easily enough.

Anonymous said...

I have a goog quality large crock and can't even get to 70 through the individual jugs,I find it easier to pan of water and jug it!

Anonymous said...

Could you heat your oils and water on the stove top and then put them in the oven for the "hold" part? pre-heated, of course.

Bilalahmad Shafiq said...

just check flash points of chemicals before heating and storing.

Susan Barclay-Nichols said...

Hi Bilalahmad! There are very few things we need to worry about heating, like fragrances and silicones. I recognize that you are new to the blog - or at least new to commenting on the blog - and we go into issues like heating, freezing, thawing, and so on in many places.

Nikos Giannakopoulos said...

Hello Susan.

I understand the need for heating oils and water at 70°C but why it should be for 20min and having to measure additional water because of evaporation?

After reading about a type of pasteurization called "high-temperature, short-time HTST", also known as Flash pasteurization in wikipedia:

15 seconds @ 70°C are enough to kill the most heat-resistant pathogenic germ

while there is a less conventional, but US FDA-legal, alternative pasteurization method (typically for home pasteurization) in which you heat milk at 63°C (145°F) for 30 minutes, which seems almost like the one that you use as it concerns the heating time.

So 70°C for 20 min isn't too much (wasted) time?

I would like to know your opinion on that.

Thank you in advance, Nikos

Susan Barclay-Nichols said...

Hi Nikos. Unfortunately, very few of us will have access to this kind of equipment in our homes, so we do what we can with what's in our workshop, like a double boiler.

We aren't just trying to reduce the germs - in fact, there is some evidence showing that we aren't really doing much in that department - we are trying to get all of our oil phase melted well and to get our emulsifier to the phase inversion temperature. Soe of the fatty acids in our ingredients don't melt until we reach 69˚C, so stopping after we reach 70˚C means not all the fatty acids are liquid. We hold for 70˚C for a while because it ensures all the fatty acids are definitely melted. As for the phase inversion temperature, I go into detail about this in the post, so can I point you back there to check out that link?

In the grand scheme of things, is 20 minutes too much time to wait to make a stable and awesome lotion?

Nikos Giannakopoulos said...

Thank you very much for your answer Susan, I just read the PIT. Very interesting information.

Nevertheless 20 min seems to me long enough for practical reasons, for small/home production that is not a very big amount, and will be consumed in a couple of months.

There is so much information here in your blog, that I would call it a cosmetic encyclopedia!

I'm on to make some facial moisturizer these days...

Thanx again


Samantha Kiffer said...

Hi Susan!

Thanks so much for all of the info! However, I've consistently been having the same problem while heating and holding my lotions and it's beginning to bug the heck out of me! It seems as though when I heat my oil phase it never reaches above 60 degrees celsius!! I've waited as long as 40 minutes and the thermometer hand never moves above 60! Meanwhile, my water phase has heated to above 80 degrees sometimes (although I stabilize the temp before mixing the two).

I'm using the double boiler method with pyrex measuring glasses. I put canning racks on the bottom of two different saucepans and set my pyrex on top of them - could this be the problem?

In addition, my second thermometer broke a while back so I've been using a meat thermometer in its place (never been used for meat either before or after crafting), could this be giving me a false reading? I notice that when I pull it out so it's only half submerged in the water phase the temperature drops drastically.

Thanks so much for all of your wonderful knowledge!

Susan Barclay-Nichols said...

Hi Samantha! I use this method as well and it works for me, so I'm not sure what to suggest. Oils should heat up easily! I'm wondering if you might want to get a candy thermometer and try that for a while? Sorry I can't be more helpful.