Blending multiple EOs - working out the maximum allowed


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May 3, 2019
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United States
Hi all,

I'm going to make an Earl Grey soap next, but I'm also ordering some ingredients for a cedarwood and orange soap!

So, I'm a newbie (...and bad at math) so please forgive the question haha. I am trying to work out how much of each EO (10x orange and cedarwood) I can add to the soap to keep it within safe levels.

On Brambleberry's fragrance calculator - in my 34oz batch, I ran the max amounts separately. The maximum is 2.04 oz of 10x orange and 1.7oz of cedarwood. I think I'll use a 2 to 1 orange to cedarwood ratio. So here is where I'm confused. Would I then add 1 oz of cedarwood and 2 oz of 10x orange to the recipe? Or would the ratio have to be a bit lower so the total amounts of EOs in the recipe don't exceed ~2 oz? I of course don't want to overdo it, but I want to add as much as I can.

Sorry, I know this is novice and I swear I read the information somewhere at one point, but it appears my Googling skills aren't as great as they used to be! Thanks a lot.


Well-Known Member
Feb 20, 2013
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Northeast Iowa, USA
Problem is 3 ounces of fragrance is 9% of your total oil weight. That's a lot of essential oil for the soap to contain. Not to mention that much fragrance could be a potential skin irritant, even if theoretically safe.

Most people don't go over 6% fragrance weight per weight of oils, assuming 6% is a skin-safe rate for the scent(s) being added. At 6% of 32 oz, that's about 2 ounces total fragrance. At a 2 to 1 orange:cedarwood, that's approximately 0.66 oz cedar and 1.33 oz orange.