What's the benefit of tea in your soap?

Well polyphenols are similar to tannins which can impart color to soaps like picture a few posts up so obviously tannins can survive the highly basic environment. One thing I did find out is that polyphenols can bind proteins and become unavailable unless exposed to a acid. So it may be a bad idea to use green tea with milk when soaping.

new12soap said:

Flashpoint and volatility are two different things. Flashpoint is the temperature at which the vapors can ignite when exposed to open flame. Essential oils do not begin to evaporate away unless and until you reach their boiling point which is much higher.

http://roberttisserand.com/2011/06/essential-oils-in-soap-interview-with-kevin-dunn/

Some interesting comments about the benefits that may remain, too.

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You are correct that the boiling point is much higher, but the flashpoint is the temperature at which the vapor pressure from essential oils (or anything else) begins to be significant (and is enough to cause ignition). There is increased evaporation at increasing temperatures, you do not need to reach the boiling point to start evaporating your EOs, this can be seen in vapor pressure charts. I was using the flashpoints as a quick guide and comparison of the temperature 'robustness' of the different EOs (one with a FP of 200F is not as much of a concern as one with FP of 105C as an example). An yes, it is much lower than the boiling point, but you can loose a substantial amount even below the boiling point. The longer the soap stays hot, and the hotter it gets, the more scent you loose from EOs with low flashpoints (and relatively low boiling points). Exposing rosemary EO (as an example) to 105F is not going to evaporate it all away, however, a gel stage of lets say a couple of hours of 160C will cause some of the EO to vaporize, even though its boiling point is much higher at 349F.

Thank you for the link on EO in soaps, it is very interesting.

That was some great information Greensoap Thank you! :-o

With respect, I want to chime in about the flash point and boiling point of a substance and how they relate to volatility -- the ability to evaporate.

The flash point is the lowest temperature at which vapors will ignite when mixed in air and exposed to a spark. The vapors may or may not continue to burn if the ignition source is removed.

Some substances do not have a flash point -- they either do not have burnable vapors, or chemically degrade before they reach a flash point, or do not produce any vapor under normal conditions. Things like gasoline, liqueurs, EOs, and FOs do have a flash point. For safety's sake it's wise to keep spark or flame away from these substances if you are working with them near their flash point.

The boiling point is where a liquid stops increasing in temperature in response to added heat energy -- all added energy goes into the boiling process only. Bubbles of vaporized material form within the liquid and rise to the surface at the boiling point. The flash point of a substance may be above the boiling point ... or it may be below. It depends on the flammability of the vapors.

Both properties are obviously related to volatility, but what I'm reading in this thread is that a substance is not volatile -- it will not evaporate -- before the flash or boiling point is reached, and that's just not true.

Long before a substance reaches its flash point or boiling point, a substance is still volatile, meaning it will evaporate. It is just volatilizing without actually boiling or burning. If substances were not volatile before their flash or boiling points, you couldn't smell bread baking, you couldn't watch vapor rise from a hot cup of coffee, and you would not be able to smell the fragrance in soap. Sheets wouldn't dry when hung on a clothesline, clouds in the sky would not exist, bread would never go stale, and your soap would never lose its scent. All of these things relate to the volatility of a substance even though the temperature is well below its boiling and flash points.

Bottom line ... respect the flash point of your EOs and FOs for safety's sake. Add fragrance to your B&B products when they are as cool as possible. Understand that volatility of a fragrance is related to temperature, time, and concentration, as well as the inherent vapor pressure of the chemicals in the fragrance.

Some compounds in an FO or EO have a higher vapor pressure than others and will not last as long. These highly volatile chemicals are the "top notes" in a fragrance. Citrus and many floral scents fall in this category. Some compounds last much longer in a fragrance. These chemicals are less volatile -- they have a lower vapor pressure -- and make up the long lasting "bottom notes". Patchouli, benzoin, frankincense come to mind.

Thank you so much for this, really helpful. I am making solid syndet shampoo and conditioner bars, and was seeing the results of volatility as you describe above but couldn't articulate it or understand it. I was falling into the trap of equating flash point with a notional evaporation/volatility point. For example, citrus EO would stick (albeit weakly), despite being added at a temperature far in excess of flash point. Then conversely a fragrance oil with a very high flash point was being totally evaporated despite being added at way below its flash point.

Having read your comments and done some further research on scent anchoring I will now
1) let the mixture cool a bit before adding the fragrances
2) add a base note of ginger EO to the citrus EO to help anchor it, and
3) add kaolin clay to also help anchor both my EOs and FOs.
I've read these things help for CP soap, so hopefully this translates to solid shampoo, where i'm trying to add fragrances at temperatures over 60 degrees C. (I tried letting the mixture cool down to around 45 degrees before adding fragrance a couple of times, but the bars just came out as mush after refrigeration, so that was a no go!)

Sophie Thwaites said:

Thank you so much for this, really helpful. I am making solid syndet shampoo and conditioner bars, and was seeing the results of volatility as you describe above but couldn't articulate it or understand it. I was falling into the trap of equating flash point with a notional evaporation/volatility point. For example, citrus EO would stick (albeit weakly), despite being added at a temperature far in excess of flash point. Then conversely a fragrance oil with a very high flash point was being totally evaporated despite being added at way below its flash point.

Having read your comments and done some further research on scent anchoring I will now
1) let the mixture cool a bit before adding the fragrances
2) add a base note of ginger EO to the citrus EO to help anchor it, and
3) add kaolin clay to also help anchor both my EOs and FOs.
I've read these things help for CP soap, so hopefully this translates to solid shampoo, where i'm trying to add fragrances at temperatures over 60 degrees C. (I tried letting the mixture cool down to around 45 degrees before adding fragrance a couple of times, but the bars just came out as mush after refrigeration, so that was a no go!)

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This post is from 2014. The poster hasn't been here in a long time.