-
precent w/w question
Was asked this question the other day, does one need density to do %w/w
example, simple formula
WATER 90% SODIUM PHYTATE 0.2% siligel 0.3% glycerin 9% ETHYLHEXYL OLIVATE 0.5% now if we’re making 100g
do you add 9 g of water which comes out to 8.5mls ( if you look at the amount you added to get 9g)
or do you add 7.143mls which is taken for Glycerol’s density of 1.26g/ml which calculates to that 7.143ml = 9g glycerol
Any takers?
Thanks
-
4 Replies
-
When using weight measurements everything is in terms of Grams. Volume does not matter.
If you want 90% water in a 100g batch, you add 90g of water
If you want 9% glycerin in the same batch, add 9g of glycerinDensity & volume do not matter.
-
Yep. thanks
-
@Perry
what is your method when going through your protocol? Say when using %w/w and you have to heat and weigh your liquids and solids? do you weigh all your liquids first on a scale then place on a hotplate then add your solids?If so, how about if the protocol calls for a strict sequence where you can’t add all liquids at once? Do you then add all ingredients in your vessel then heat and stir?
thanks!
-
Typically, you weigh your ingredients in weigh boats (something like these)
You can pre-weigh all your ingredients, but you can also weigh as you go. You should follow the proper sequence and not add any ingredient at the same time. I always tried to imagine what a compounder who was making a 3000 gallon batch would be able to do. Ultimately, your manufacturing procedure needs to be scalable.
Log in to reply.