Classic Bells > Soapy stuff > How to use ppo

How to use "ppo"

Many recipes use the abbreviation "ppo" when measuring fragrance and other ingredients. What does "ppo" mean?

The abbreviation "ppo" literally means "per pound of oils." It means you should calculate the amount of an ingredient based on the total weight of fats in your recipe. Do not include the weights of anything else -- water, alkali (lye), or other ingredients.

The total weight of "oils" includes actual oils (liquid fats) as well as solid fats and a few ingredients that are usually treated as if they are saponifiable fats. Examples of these "non-fat fats" include beeswax, pine tar, stearic acid, and lanolin.

How do I calculate ingredient amounts if they are based on ppo?

"Ppo" is used in two different ways -- one way is with percentages and the other is with weights or volumes.

A percentage "ppo" is telling you to calculate the weight of fragrance or other ingredient using the total weight of oils.

A recipe might say to use "3% ppo" of an ingredient. This is a percentage-ppo measurement.

Percentage ppo is used like this --

ingredient weight = Total fat weight X Percentage-ppo / 100

Example: My recipe uses a total of 1600 grams of fat. I want to add fragrance at 4% ppo. How much fragrance should I weigh for this batch?

Fragrance weight = 1600 X 4 / 100 = 64 grams

 

A weight-based or volume-based "ppo" is telling you how much weight or volume of an ingredient to add for every 1 pound (16 ounces by weight) of fats in your recipe.

A recipe might say to add "2 teaspoons ppo" of an ingredient. This is a volume-ppo measurement.

It might call for "9 grams ppo" or "1.5 ounces ppo". These are weight-ppo measurements.

Weight-ppo or volume-ppo is used like this --

1. If needed, convert total weight of oils in the batch from grams to pounds --

Oils in pounds = Oils in grams / 454

2. If needed, convert total weight of oils in the batch from ounces to pounds --

Oils in pounds = Oils in ounces / 16

3a. If using weight-ppo, calculate the weight of an ingredient --

Weight of ingredient = Weight-ppo X Oils in pounds

3b. If using volume-ppo, calculate the volume of an ingredient --

Volume of ingredient = Volume-ppo X Oils in pounds

Example: My recipe calls for 600 grams of fat, total.
I want to add fragrance at 3 ounces ppo.
I want to add colorant at 5 grams ppo.
I want to add activated charcoal at 1.5 teaspoons ppo.
How much of each of these ingredients should I use for this batch of soap?

Oils in pounds = 600 grams / 454 = 1.32 pounds

Weight of fragrance = 3 ounces ppo X 1.32 pounds = 3.96 ounces

Weight of colorant = 5 grams ppo X 1.32 pounds = 6.6 grams

Volume of activated charcoal = 1.5 tsp ppo X 1.32 pounds = 1.98 tsp

--------

Extra credit. What does percent mean?

"Percent" is a mashed-together English word that was once written as two separate words -- "per cent." (1)

The word "per" means to divide. The word "cent" stands for 100 (100 cents in a dollar, century is 100 years, centennial is a 100 year anniversary, etc.)

Whenever you see a number followed by a % sign or the word "percent", this means the number should be divided by 100. Examples --

5% = 5 per cent = 5 / 100 = 0.05

33% = 33 per cent = 33 / 100 = 0.33

0.02% = 0.02 per cent = 0.02 / 100 = 0.0002

125% = 125 per cent = 125 / 100 = 1.25

(1) "...Percent is from the Latin adverbial phrase per centum meaning "by the hundred." The Latin phrase entered English in the 16th century. Later, it was abbreviated per cent. with a final period. Eventually, the period was dropped and the two parts merged to produce the modern one-word form percent...." Dictionary.com entry for the word "percent" found at https://www.dictionary.com/browse/percent