Formulating Using Percentages: Why And How?

I see many recipes out there using volume measurements and technically this is an incorrect practice.  The reason for this is two fold: volume is an inaccurate measurement and there is no way to determine what .5% of an ingredient is in volume measurements.  Plus unless you have extremely accurate, expensive, lab equipment and can read a meniscus properly, you will never have precise measurements using volume.

 

So what is the proper way? 

The proper and accurate way to formulate a recipe is in weight measurements and this is why you often see recipes in percentages as they convert to one another easily.  Metric measurements (grams) are the most precise way to get consistent results every time. 

 

Percentages allow us to increase or decrease a batch size with ease.  We do not have to worry about only being able to half, double or triple the batch, etc.  We can take a 1200 gm batch and convert the measurements to 2200 gm easily using the percentage method. 

 

How do I change my volume recipe to weight measurements?

If you have a tried and true recipe that is in volume, you can easily convert it to weight by taking the volume measurement of the ingredient and weighing it out on a scale (I suggest purchasing a scale that is precise to at least a gram, as when dealing with specialty additives and preservatives you will need it.  Canadian Tire often has these scales on sale for a decent price). 

 

As an example: Your recipe calls for ¼ cup of Jojoba Oil.  Take your empty measuring vessel (measuring cup if that's what you normally use) and place it on your scale. Tare your scale to zero. Add your 1/4 cup of oil to the measuring vessel and it will read you the weight of the oil.  This will be your new measurement value for your Jojoba oil (I suspect the reading will be in the neighbourhood of 52 gm, but this is only because I know the density of the oil (862 gm/L) and ¼ cup is 60 mL or so.  **Note: 60 mL of oil does not equal 60 gm.) 

 

Do this with each and every ingredient.

 

Converting recipes to percentages.

Now that you have the weight values for each of your items calculated, it is time to convert them to percentages.  I will use one of my recipes as an example. 

 

The recipe is:

 

  • Distilled Water  726 gm
  • Hydrolyzed Silk 24 gm

 

  • Calendula Oil   54 gm
  • Jojoba Oil  57 gm
  • Fractionated Coconut Oil  102 gm
  • Avocado oil 54 gm
  • Shea Butter  48 gm
  • Virgin Oil de Coco Creme  48 gm
  • Emulsifying Wax  60 gm
  • Stearic Acid  6 gm

 

  • Cosmocil CQ (Preservative)  5 gm
  • Allantoin   6 gm
  • Vitamin E  6 gm
  • Fragrance  4 gm

 

Total up all of your recipe weights by adding them together.  In this case the total recipe weight is 1200 gm.  This is the number we are going to use for each calculation. 

 

Take the weight of your first item (in this case Distilled water) and divide it by the total weight.  Multiply this number by 100 to get the percentage. 

So as an example:  726/1200 = 0.605 x 100 = 60.5%

 

Do this with every item in the recipe. 

 

We now have a recipe that looks like the following:

 

  • Distilled Water  60.5%
  • Hydrolyzed Silk   2.0%

 

  • Calendula Oil   4.5 %
  • Jojoba Oil  4.8%
  • Fractionated Coconut Oil  8.5%
  • Avocado oil  4.5%
  • Shea Butter  4.0%
  • Virgin Oil de Coco Creme  4.0%
  • Emulsifying Wax  5.0%
  • Stearic Acid  0.5%

 

  • Cosmocil CQ (Preservative)  0.4%
  • Allantoin   0.5%
  • Vitamin E  0.5%
  • Fragrance  0.3%

 

 If you total up all the percentages, you should get 100% at the bottom of your recipe.

 

Voila!  You have your recipe in percentages.

 

Taking your converted recipe and turning it back into a batch size. 

So let’s say you now would like to make a batch 2200 gm in size.  How do we do this?

 

For each ingredient percentage you will follow the following math formula:

(% divided by 100) x Total Batch size. 

So in the case of the distilled water:  60.5/100 = 0.605 x 2200 = 1331 gm. 

 

Do this throughout your entire recipe.  To make sure you did not make any mathematical errors add up your ingredient weights and they should equal 2200 gm.  If they do not, you made an error in your math somewhere (you may be out 1 or 2 grams due to rounding, if this is the case, don't fret, remove those grams from your water phase, if you have one.  If you do not have a water phase, remove them from your bulk oil). 

 

So our above recipe now looks as follows:

 

  • Distilled Water  1330 gm*  (The actual amount was 1331, but to total the recipe to 2200 gm, I removed a gm as it is a rounding error.)
  • Hydrolyzed Silk 44 gm

 

  • Calendula Oil   99 gm
  • Jojoba Oil  106 gm
  • Fractionated Coconut Oil  187 gm
  • Avocado oil 99 gm
  • Shea Butter  88 gm
  • Virgin Oil de Coco Creme  88 gm
  • Emulsifying Wax  110 gm
  • Stearic Acid  11 gm

 

  • Cosmocil CQ (Preservative)  9 gm
  • Allantoin   11 gm
  • Vitamin E  11 gm
  • Fragrance  7 gm

 

So, it may seem like another language right now, but after some practice, you will find that it is a lot easier to manage batch sizes and stay consistent.  Plus, the recipes posted in percentages will not seem so complicated.  The other good thing about percentages, is that we are more capable of helping you tweak or adjust your formula as we think this way at Creations from Eden.  So, practice makes perfect!  Have fun!

 

If you have MS Excel, I have created three FREE basic calculators for you that will convert all of your formulas, if you know the weight of the ingredients in your recipe.  You can download it by clicking here.  Basic instructions are provided under the calculators.  Please read the above to understand what numbers you are looking for in the calculator.  I know, I could have posted this first, however I wanted you to work for it and understand why you are doing what you are doing :)

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