Ratios, Percentages and Parts Per…

Sometimes I am so confused when I start reading recipes or other important papers that reference ratios, percentages and parts per (fill in the blank). Over the weekend, I had a stunning revelation that clarified all of these confusing terms for me.

This revelation came as I was making grits for our family breakfast and wanting to have enough left over to feed chickens.

How did this come about while making breakfast? The yellow coarse cut grits that we use needs 4 parts water and 1 part grits, also known as a 4:1 ratio. This is a total of 5 parts. Before, I always just asked how much water and how much grits I needed to measure.

This revelation made me understand that I can alter the recipe to equal how much I want to make. For example, if I wanted to make grits for just myself, I would use 1 cup of water and 1/4 cup grits. If I wanted to feed a family of 4 and give a small flock of chickens the leftovers, I would use 8 cups of water and 2 cups of grits. The percentages are 80% water and 20% grits.

Most fragrance blends are done in parts. For example, the Halloween Candy Bag blend I made last week is a 3:1 ratio. That’s 3 parts Lemon Sugar type Fragrance Oil and 1 part Cinnamon Bear Fragrance Oil. This is a total of 4 parts. It could also be shown in percentages: 75% Lemon Sugar type Fragrance Oil and 25% Cinnamon Bear Fragrance Oil.

If you can count pennies, nickles, dimes, and quarters to make a dollar, then you already know how to use percentages. Pennies are the equivalent to 1%. Nickles are the equivalent to 5%. Dimes are the equivalent to 10%. Quarters are the equivalent to 25%. You must be able to create something that is equal to $1.00 using different combinations of these four coins. Just like making $1.00, you must make 100% using percentages. You can’t make 98%, 99% or 67% – you must make 100%.

What if you have a lotion recipe that weighs 10 ounces and you need to use a preservative? How do you calculate a preservative for that?

Let’s say that we were going to Liquid Germall Plus as our preservative. It has a usage rate of 0.1% to 0.5%. How much is that?

Let’s start with 0.1%.

10 ounces x 0.001 (0.1%) = 0.1 ounces to be added to lotion

Now let’s try 0.5%.

10 ounces x 0.005 (0.5%) = 0.5 ounces to be added to lotion

How did I calculate that 0.5% is equal to 0.005? I removed the percentage sign, and moved the decimal point two places to the left. Even if I was calculating 15%, the decimal point would still move two places to the left. Now, 15% is 0.15 and easy to multiply, because this is the same as if I had 15 cents.

Now onto parts per (fill in the blank). Usually, we see the term parts per million, abbreviated as ppm, on a Certificate of Analysis. This usually tells us how many parts of something there are in a million. If we used the ratio for hummingbird sugar water (4 parts water and 1 part sugar, which is a total of 5 parts), what would the parts per … be? The sugar would be 200,000 parts per million parts of solution.

Let me show you a comparison between ratios, percentages and parts per … using the Halloween Candy Bag blend.

I hope my revelation has made sense to you.

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