# Stupid question but it keeps confusing me about E.O usage rates?



## mikvahnrose (Sep 24, 2016)

I keep seeing people interchange usage rates of E.O on here.

Some people say .5%/oz PPO and other say 5% PPO which are very different things.

Which one is correct when adding to soap. 

Say you have 100 oz of oils for soap. Do you add 5 oz of e.o or 2.5oz? Less? More? 

I have generally added about a tsp of e.o PPO. But am trying to get into percentages and it's been a long time since i have used %'s.


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## Susie (Sep 24, 2016)

It is up to you.  And you will find that you will have a different usage rate based on your experience of how that EO behaves in soap.  But do pay attention to maximum usage rates on irritating EOs, such as peppermint and cinnamon.


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## DeeAnna (Sep 24, 2016)

Either one is correct as long as the usage is clear. You wrote ".5%/oz PPO" and I don't really know what that means -- you're mixing your units. I assume you meant 0.5 oz ppo. 

0.5 oz ppo (per pound of oils) is a dosage rate specifically based on the Imperial measurements of pounds and ounces. It has nothing to do with percentages. It means for every 16 oz (1 pound) of fat, you will use 0.5 oz fragrance.

5% ppo is independent of the units of weight. In this case "ppo" is merely telling you that the dosage rate is based is on the weight of the fats -- stated more accurately, it means "per _weight_ of oils". For every unit of weight of fat you will use 5/100 units of fragrance. For 1 pound of fat => 5 / 100 X 16 oz = 0.8 oz fragrance. For 200 grams of fat => 5 / 100 X 200 = 1 gram fragrance.

Some of us were kidding around awhile back and came up with an alternative of "pow" instead of "ppo" to stand for "per oil weight". POW makes more sense than PPO but I doubt it will become popular.


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## joy. (Sep 27, 2016)

It depends on what oil you're using. Some can be used at 5% of total oil weight, others can only be used safely at .05% of total oil weight, or even less. Some have no restrictions, so you can get crazy and add more. Some can't be used on the skin at all.

The book "Essential Oil Safety" by Robert Tisserand clarifies and explains things very well. I highly recommend reading it.

You can look up safe amounts on the IFRA website as follows:



joy. said:


> 1. Get the MSDS (safety data sheet) from the manufacturer of your oil. It will list the main constituents of the oil you have. Constituents vary, so don't rely on what someone else is using or says is safe - get the sheet for the specific oil you're using. You can find that info on the MSDS under section 3.
> 2. Look up the constituents in the IFRA library: http://www.ifraorg.org/en-us/standards-library
> 3. Calculate your safe EO amount based on the max. amount for each constituent in your oil blend.


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## mikvahnrose (Sep 29, 2016)

joy. said:


> It depends on what oil you're using. Some can be used at 5% of total oil weight, others can only be used safely at .05% of total oil weight, or even less.



This is what confuses me. So 5% out of a hundred written in decimal form is .05. So like 5% of 100grams of oil is 5 grams.

But does that mean when you say .05%, you are saying it is 5% of 1%?


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## Susie (Sep 29, 2016)

mikvahnrose said:


> This is what confuses me. So 5% out of a hundred written in decimal form is .05. So like 5% of 100grams of oil is 5 grams.
> 
> But does that mean when you say .05%, you are saying it is 5% of 1%?



Yes, that is what she means.  Some EOs are extremely irritating.  Although I tend to use the website of whomever I order the EOs from for safe usage rates.  I simply copy/paste the info into a file I keep on my computer.  I do date and label the file with the name of the company.

I also used this site to know which EOs I had to pay particular attention to until I got the list of the EOs I prefer to use down. 

http://naha.org/index.php/explore-aromatherapy/safety/


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## dixiedragon (Sep 29, 2016)

> Some people say .5%/oz PPO and other say 5% PPO which are very different things.


 
I am not mathy at all. I rely on the soap calculator to determine my amount. You can check out fragrance calculators - Majestic Mountain Sage has one, and Brambleberry has one. You can enter the type of product (soap, lotion, etc) and it will give you a recommended range of amounts to use.

I'm honestly not sure what .5%/PPO means. Can you point out where that was said? I'm thinking it was actually .5 oz PPO, which is not a bad "rule of thumb" for EOs. It's not great b/c EOs can vary widely, but you could probably get away with it. I don't think 5% PPO makes sense either. Maybe that was 5% of oil weight?


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## mikvahnrose (Sep 29, 2016)

Hi Dixie. I mean .05% ppo. Sorry for the (slash) sign. 

I remember reading a thread wayyy back on here that a person kept using the term's 5% and .05% interchangeably when they are really different in percentages. And that is what was confusing me. 

As one is half a percent. And another is 5% of a hundred but she was speaking for the same product used in the same batch of soap.


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## Scooter (Sep 29, 2016)

First I need to say that I am not selling my soap, or even gifting it right now. I have only been doing this since July and out of the 8 or so batches I have made thus far, only 2 have fully cured. Also, I prefer unscented soap anyway. But I have been experimenting with tea tree and lavender.

Anyway, the more I learn about IFRA, the more I realize I really need to study a lot on this to get just a minimal level of understanding. There are lots of resources out there to study, too. One thing I ran across that seems like a pretty good rule-of-thumb guide is this: http://www.modernsoapmaking.com/essential-oil-usage-rates-ifra-guidelines/. This soaper gives *her* personal maximum use for different products but her opinions seem really well researched.

Also, ditto what the other comments on this thread have said.

--Scooter


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## dixiedragon (Sep 30, 2016)

mikvahnrose said:


> Hi Dixie. I mean .05% ppo. Sorry for the (slash) sign.
> 
> I remember reading a thread wayyy back on here that a person kept using the term's 5% and .05% interchangeably when they are really different in percentages. And that is what was confusing me.
> 
> As one is half a percent. And another is 5% of a hundred but she was speaking for the same product used in the same batch of soap.


 
But .05% ppo still doesn't make sense. Or 5% PPO. I think somebody made a typo on this!

On 5% vs .05% - obviously those are very different! I am thinking the confusion might be that if you want to get 5% of something, you multiply by .05? And somebody was hurriedly typing and accidently added the % to the .05?


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## DeeAnna (Sep 30, 2016)

The term "ppo" was created when soapers worked in pounds and ounces and weren't trained in science. Its use today is based more on habit and less on whether it's strictly correct. Its a way of saying to do the calculation based on the fat weight rather than the total recipe weight (fat + lye + water) or something else.

When ppo is used with a percentage -- 5% ppo for example -- ignore the "pounds" as the units of measurement. Percentages are independent of units -- it doesn't matter whether you're using grams, ounces, or whatever. The use of "ppo" means "the measurement is based on the weight of fats in the recipe". Here is an example:

For 100 grams of fats:
5 / 100 X 100 = 5 grams

For 16 oz of fats:
5 /100 X 16 = 0.8 ounces

0.05% ppo is ALSO a valid percentage. Again "ppo" simply means "on the basis of the fats in the recipe".

For 100 grams of fats:
0.05 / 100 X 100 = 0.05 grams

For 16 oz of fats:
0.05 /100 X 16 = 0.008 ounces

This tiny weight is not meaningful in soaping, but you are going to have to go back to the originator to figure out what she really meant. There are a LOT of math challenged soapers out there who really don't deal with percentages very well, so they get easily confused about how to present information in percentages.


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## joy. (Oct 2, 2016)

If it helps with the math, my smart phone has a % key in the calculator - I'm guessing they all do. It makes it super easy to calculate percentages without having to convert to decimals.

So, to calculate 5% of 16oz oils it's just: 16 x 5% = 
For half a percent of 16oz, it's 16 x .5% =

Instead of 16 or 32oz, I usually do batches in 10, 20, 30, 50, or 60oz, and the math gets even easier...though I still don't trust myself to calculate in my head


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