Reader Question - Percentages

In regard to preservatives, I know there is a certain percentage required to add to a product, but how do I determine the amount? (is there a mathematical formula?) For example, if I make a 16 ounce batch of lotion how do I determine the amount/percentage of preservative to add? ~ Charlene

Hi Charlene,

Thanks for another very good question!  Most Preservatives should have a recommended usage rate.  At From Nature We Love, we post these rates in each Preservative's product description.  If you can't find the usage rate online, contact the manufacturer or supplier to find out what it is.  Usage rates are also used with many other kinds of additives and ingredients.  Once you know the rate, you'll need to determine how much of your recipe works out to that rate.  I'll use an example of 5% as a usage rate to show you a simple way to do this.

Let's say you were making a 16 ounce batch of lotion.  The easiest way to work with that amount is to first convert it into metric terms.  Using an online conversion calculator, convert 16 ounces into grams.  It should work out to about 456 grams.  Now, use a regular calculator to determine what 5% of 456 grams is.  You should come up with a result of about 23 grams.  You can either measure your Preservative or additive in grams, or you can convert it back to ounces.  In this case, 23 grams would work out to about 0.8 ounces.

Do you have any tips on how Charlene can easily determine a percentage?  If so, please share them with us in the comments below.

Comments

[erica]

I recently ordered the organic liquid castille soap. I like it, but it's too liquidy. Can I heat this liquid and then add alcohol and glycerin to turn it into a "GEL" consistency? My goal is to make a "GEL" consistency using a pre-made liquid soap (without having to make it from scratch.)Thanks.

[Kassie]

I believe that you can thicken liquid castile soap by heating it gently and adding a small amount of salt water to the soap while stirring. I have not tried this myself yet but plan to give it a try. If you are successful at thickening your base using this method or any other methods (by adding vegetable gums or heating off some of the water), please let us know!