Hot Process Fragrance

[Countryside]

Hi. I have a quick question. I have been making CP soap for a while and have started working with HP. The usage amount for the FO that I use is 5%. My question is does that apply to both CP and HP? I have searched the internet and thought I saw something that said HP fragrance should be added at 2%. The reason I ask is because I am having an issue with the fragrance fading. I add the fragrance around 160 degrees. Is there something that I am doing wrong? I do not have any issues with the same FO with CP. Any advice would help. Thanks.

 

[gloopygloop]

Here in Europe the maximum usage rate for FO is 2 to 3% but more often 2% I make HP and have never used above 3% and mostly use 2% without any problem and finished cured soaps smell nice and noticeable. There are of course some FOs which will fade no matter what you do so those you just have to move away from and go with the ones which do stay. You are in the US and therefore not governed by the rules in Europe however the rules were made because of safety issues and skin sensitisation, I could not imagine using a soap with 5% percentage FO but I think in the US it maybe commonplace.

Usually you can get away with a little less FO in HP as it does not get reacted with the lye.

 

[lsg]

Most of my suppliers list the maximum usage rate for each product. Brambleberry.com and Wholesale Supplies Plus have fragrance calculators.

 

[Countryside]

Ok. Thanks. It may just be that particular FO. I will continue testing. Thanks so much for the reply.

 

[Obsidian]

You also need to know the flash point of the FO you are using. If its 140 and you add it at 160, the scent will mostly cook away.

When I make HP, I always put the soap in a large stainless bowl before scenting so the FO doesn't burn off on the hot crock pot liner.

 

[Countryside]

Ok. I will try that as well. I usually add while still in the crock pot.

 

[amd]

@Obsidian flash point doesn't have anything to do with scent burnoff. See DeeAnnas comments in link below explaining it.
https://www.soapmakingforum.com/threads/favorite-fragrance-calculator.71720/page-2
Grrr tried editing to fix the URL to go directly to DeeAnna's post but my phone and the forum aren't cooperating. You may have to skip down a few posts on the linked thread. Sorry about that.

 

[jcandleattic]

You also need to know the flash point of the FO you are using. If its 140 and you add it at 160, the scent will mostly cook away.

FALSE
Flashpoint has nothing to do with the temp of when an FO will "cook away"
Scent "cooking away" has to be at a high sustained heat for a LONG time before the scent molecules are gone.

Flashpoint is literally this and nothing else: The temperature in which a volatile liquid comes in contact with a spark and ignites.

 

[Obsidian]

All I know is if I add scent to batter that is too hot, it vaporizes and disappears. I watched it flat out burn once when in contact with the crock pot liner.

 

[jcandleattic]

All I know is if I add scent to batter that is too hot, it vaporizes and disappears. I watched it flat out burn once when in contact with the crock pot liner.

That may be so, however, that has nothing to do with flashpoint.
I've never had that happen with any scents I've used in my HP process (and have used FO's with a FP as low as 100), and I put my scent in right after the cook, in the crockpot before putting it into the mold.
If my scent disappeared that quickly, when I HP'd, I'd look into the scents I was using and wonder why. However, I know you've been soaping for a long time and presumably use reputable FO companies, so am not sure why that is happening.

The only time I've ever had scent dissipate quickly due to heat is when my wax was sustained at/above 250°, and even then it took about 35-40 minutes at least, before it was gone.

And, as usual, DeeAnna was more elegant with her explanation. (I didn't see amd's post before I posted)

 

[gloopygloop]

I have rebatched soap with added FO at high temperature and after moulding and cooling its aroma has not changed. I too always understood that flash point was not burn off, I have never had an FO burn off personally.

 

[Countryside]

It may just be the amount of FO that I used in the CP vs HP. The scent does not disappear or burn off but it is noticeably not as strong. From my understanding 5% fragrance was acceptable in soap. This is also the maximum amount recommended for that particular FO but I have not read or found any information that states that this percentage is acceptable in HP.

 

[jcandleattic]

I have not read or found any information that states that this percentage is acceptable in HP.

It is acceptable in HP, however I rarely ever go above 3% FO in my HP, and my HP soaps are just as strong (if not stronger) than my CP soaps because the saponification process is already complete.

 

[Bladesmith]

I only do HP and I always add the fragrance as the last thing right before putting the soap in the mold. My soap is usually 190F+ at that point and, while I have noticed something like steam rise up after putting the fragrance oil in, I've never had any issues with the fragrance going away.

 

[msunnerstood]

I also soap hot but I do wait until the soap cools a bit before adding FO and I do it right before I pour it. I typically use 3-4% of FO.
From my experience, the sticking power depends on the fragrance. I can use the same amount of one fragrance and have t last while another batch with another fragrance doesnt.