2 Scent Retention questions

[Carl]

Hi everyone,

I have 2 quick questions regarding scent retention.

1. Can a water discount help with scent retention? I'm thinking as the water leaves the bar during the curing process, can it possibly be picking up some scent molecules and taking them with it?
2. Are there any base oils that are better for scent retention? Any that are worse? Or are they all just equal?

Thanks ahead of time!

 

[cmzaha]

No to both. Your FO is going to determine how long the fragrance sticks and most EO's will fade

 

[Susie]

^^^What Carolyn said! But some EOs stick just fine. It's just that FOs are so much cheaper!

 

[DeeAnna]

Here are my opinions, speaking of bar soap --

1. No. I don't see that using less water does much, if anything, for retaining scent.
2. I don't think there are any better or worse fats for scent retention in soap. The fats saponify into soap, so the "base oils" aren't base oils anymore, for one thing. But try an experiment to see for yourself -- put one fat or oil in a small open container, add scent to it, and see how long the scent lasts. Repeat with several other fats/oils of your choice.

There is no scent in soap that is going to ever stay knock-your-socks-off strong as time passes, even if it starts out that way.

Fragrances with low volatility -- patchouli, sandalwood, dragons blood being examples from the EO world, although there are FO examples too -- are going to last longer than fragrances with high volatility -- citrus EOs being prime examples.

But they will all gradually fade over time. That's just the nature of scent -- fragrance can only be smelled if it evaporates, but by evaporating, the scent will inevitably fade.

There's also another issue in that I think some scents gradually alter and become less fragrant with exposure to the alkalinity of soap.

Ways to slow the loss of scent -- Use lower volatility scents that remain stable in soap (ones that others report as "sticking" in soap). Use storage and packaging methods that reduce the evaporation rate of the scent while on the shelf. The soap could also be stored in a cool or cold place if practical, because lower temperatures reduce volatility.

Or make liquid soap, scent it with soap-stable fragrance, and package the soap in bottles. That works real good ... but I know that's not where you're going with this thread, Carl.

 

[amd]

A soapmaking friend of mine, whose husband is a chemist, and I had an argument regarding adding fragrance at trace (recommended by the chemist) vs adding fragrance to the oils prior to adding lye (my method). His reasoning:

1. You are volatilizing it off as you are mixing and creating ideal conditions to purge the scent out*
2. the scent is sitting in a basic environment for longer and getting hydrolized by the sodium hydroxide*

Bonus information from him: Why is this worse than going through gel phase? Once it is at the gel phase you've already reacted some of it (scent) to a solid on the top and you've already reacted a lot of the sodium hydroxide into soap.*

*My friend recorded her husband explaining this, so I have transcribed his words here so I wouldn't screw up the words and miss his point.* (Cuz that would happen...)

So, according to the chemist husband, when you add the fragrance to the soapmaking process can help scent retention. I'm not a chemist, and but here's my opinion: for my recipe/methods it really doesn't matter. I take my soap to emulsion in about 30 seconds, it will go to trace in about a minute but I rarely intentionally go to trace. Even separating and coloring before adding fragrance, would be about two minutes more time. All said, (again, for my recipe) I don't think that those three minutes have any impact to how strong/long my soap holds fragrance. My friend's recipe requires 8 minutes of continuous stick blending to get to trace, which to me would have more impact to reason #1 above. For me... well, given the short amount of time I spend mixing, and the very probable likelihood of me forgetting to add my fragrance... I won't be changing my methods. [I'm such a rebel...]

What you can take from this: If your recipe is slow tracing and you spend quite a bit of time stickblending, consider when you are adding your fragrance. OR you can shoot all the holes you want into the Chemist Husband's reasoning. I did breeze through the Scientific Soapmaking book to see if KD had any thoughts on fragrances, but I didn't see anything regarding it - I may have missed it if he did - but that is all the research I have applied on my own due to a crazy time crunch this week.