If a recipe says add 1% of something, how do you work that out in grams? All my recipes are in grams, and ive no idea how to convert that to percentages.
Once you know how to convert percentages into grams, then you can take all your gram recipes and convert them into percentages. That will allow you to make batches of any size. Having all your master recipes in percentages is a big time saver as once you have that...you can re-batch at pretty much any size.
Converting weight to percentages:
Number of grams (per ingredient) x 100 divided by the total grams
For example: your formula is a total of 75 gms in weight
40 grams of your formula is grapeseed oil
23 grams is coco butter
10 grams is beeswax
1.5 grams is your fragrance
0.5 grams is Vitamin E
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75 grams total in your formula
(40 (grapeseed oil) x 100) / 75 (your total batch size) = 53.3%
(23 (coco butter) x 100) / 75 (your total batch size) = 30.6% This was actually 30.66 so you could round it off to 30.7%
(10 (beeswax) x 100) / 75 (your total batch size) = 13.3%
(1.5 (fragrance) x 100 / 75 (your total batch size) = 2%
(0.5 (vit E) x 100 / 75 (your total batch size) = 0.6 (again this was 0.66 and could be rounded up to 0.7)
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99.8% total
Now this happens if you don't round up or down and in many formulas and you have to decide at this point where you want to put that extra 0.2%. In this particular case just rounding up the coco butter and Vit E will even out your formula, but sometimes it will give you more than 100% especially if you have a lot of ingredients. You just have to look over your formula and decide where you want to add or subtract to reach your goal of 100% and than you have your master batch recipe that you can convert into any size you want.
Keep in mind that if your product is a hit and you will be taking it national or something like that with huge batches being made, that fudging around with the rounding up and down could get you into trouble.
You can avoid this by experimenting with batches of 100 grams, then everything will be evened out.