I was fortunate quite a few years ago to be able to communicate with the late Maurice Hevey who was a cosmetic chemist who was on a Yahoo Cosmetic Chemistry message board and he helped many people (just as Perry does now) to understand the basics of cosmetic chemistry and the specialized characteristics as well. I learned very early on about formulas so I am quite familiar with the 100 percent base of all formulas.
Lathering Shaving cream became quite popular starting in the 1920’s and the formulas and ingredients lists from those times are still exactly the same on current products as they were back then because they work well! There are quite a number of books that contain formulas for this type of shaving cream dating back to that time especially in the 20’s, 30’s and 40’s and they either can be found in cosmetic chemistry formula books or soapmaking textbooks. Cosmetic Chemistry procedure has changed greatly in the last 100 years so it is not unusual to look back at an old book and find some procedures that are now questionable. That is why I asked the questions I did.
I haven’t noticed any current formulas (for any kind of products) that mention having an evaporation percentage but I have seen some that say you should add back any of the evaporated water to the batch of that particular product. Also, the procedures listed in these old books such as stirring something on heat for a certain period of time would cause evaporation so I am now looking at the production procedures from some of these old formulas to see if they have techniques like those listed! That tells me something about that formula and answers the questions as to why some of the old formulas have larger water phases than the others!
Because my batches are relatively small, I can easily add the amount of water that evaporated, the next day and homogenize it. A large production company probably can’t do that quite as easily as I can. So it would behoove them to have a larger water phase to account for the water loss during their production which is why some of these old formulas have larger water phases. Because of this, it will tell me what size water phase I need in creating my formulation. So the formulas with procedures in them can tell me quite a bit more about them than those without! Obviously comparing phase size, ingredients and procedures can as well! Having this knowledge helps me to understand which old formula will be more helpful to me to create a new formulation!
Also, I did know that it was the water that was evaporating in the formula because none of the other ingredients have the ability to evaporate I just needed to know if it was 10% of the total formula (not the water phase) and if they had written it this way I wouldn’t have felt the need to just verify what I thought all along! - “Note: The loss of water is approx. 10% (of the total formula)”