As you may know, I have a shaving cream project I have been working on for the last three months. In reviewing everything, I have found that some of my problems with this formula have come from rounding off some of the numbers from within the formula. My original formula did not have enough of the bases (hydroxides, TEA) to full saponify the oil phase, I also added a them as well as a preservative, EDTA and I added the required amount to the formula to get the results I wanted, but it brought the formula up to around 108%. Some of the numbers added to the original formula were the required numbers for a 100% formula and needed to be higher to work with 108% total. My solution was to try to get everything up to 110% which I thought would make it easier to reduce it to 100% number-wise. Part of the problem was that in adding extra ingredients, I used the percentage required for a 100% formula but I actually needed more to provide enough of each of those ingredients to work with the 110% amounts. The problem lies with the resultant percentages with all those extra decimal points! One example would be an amount that came up to 41.398% which I rounded off to 41.4%...not a problem but when I got to the end of rounding off all these numbers, I had to add .75% to the water phase. It many not be a problem but keeping the oil phase and water amounts within a certain range does affect the end result in this product which you may have read created one version of my product that went back and forth between solid and liquid!
So how do you guys do it? It has turned out to be quite a balancing act and I'm really close but I want to understand better how this should be approached. Does one of Perry's videos address this issue or is there some basic cosmetic chemistry book that may cover this? Your input will be greatly appreciated!