Blending Fragrance Oils

[cappykat]

I want to blend two fragrance oils. They are both Black Raspberry Vanilla. One has an IFRA of 3.42% and the other is 25%. I have 1.30oz of the 3.42% and 1.95oz of the 25%. I have 42oz in oils. Here's the math:

42 x .0342 = 1.43oz (I'm using 1.30oz which is 3.1%)

42 x .046 = 1.93oz (this is the 25% IFRA)

Total FO 3.25oz

In Soapcalc.net I used a 1 fragrance ratio which is .0625%. (42 x .0625 = 2.63oz) My calculations using both FO's give me a 7.7% total fragrance percent. Is this allowable?

 

[akseattle]

@cappykat , I have blended some fragrance oils where one had a low IFRA- like 3.42% , and I added an FO with a higher IFRA, like13%, until I had a combined 6%. I only recently started wondering- since I have no idea what in the FO gave the first FO a low IFRA, and I have no idea what is in the second FO, how to know if it is safe.

I was just about to ask this question. How to know if a combination of FO's is safe. So, I look forward to seeing how others figure this out.

 

[AliOop]

since I have no idea what in the FO gave the first FO a low IFRA, and I have no idea what is in the second FO, how to know if it is safe.

That's the concern I'd have, as well. Not sure how to resolve it.

 

[paradisi]

You need to find the chemical that's responsible for the limits. Generally speaking nowdays the EU allergen sheet and/or SDS will show the aromachems that have limits and you can figure it out from there.

You will have to look up those to see what their limits are. Then it's just math.

Example: If frag A has 80% of Limited Thing, 1 oz has 0.8 oz, right? And if Frag B has 5% of that Limited Thing, then an ounce of it will have 0.05 oz. Added, that's 0.85 oz in the two combined ounces. Etc.

But without those info sheets, you can't know if it's going to surpass the IFRA limits to blend them.

 

[Saponificarian]

The EU allergen sheet is your best bet, and I calculate it as @paradisi suggested above, which is how I make my FO/FO and EO/FO blend. Do the calculation before you start so you don't blend, tweak it to get the right blend and then find out you have exceeded the IFRA limit. Ask me how I know each tweak's IFRA must be calculated before making an additional tweak.

 

[akseattle]

@paradisi and @Saponificarian ,
" EU allergen sheet and/or SDS will show the aromachems" that sounds greek to me and very complicated. Just when I thought I was getting a handle on these soaping basics. Well, I've decided to stay away from FO's that are low on the IFRA chart. Not to be an uncreative wimp, but for now, I may have to stick to what someone else has already mixed commercially.

 

[lucycat]

Another way is to pretend you are making 2 soaps each with 21 oz oils. Calculate the FO for each 21 oz "batch" according to IFRA &/or use rate and then combine the two calculations for your 42 oz batch.

 

[akseattle]

@lucycat , what I've done up to now is as follows: If IFRA is 4%, I put in 4%, then I add 2% of anything else that has IFRA of 6% or more. But, this doesn't seem to consider the specific bad actor in FO #1. If FO #2 also has the same bad actor, then it seems like I would exceed IFRA.

 

[lucycat]

@lucycat , what I've done up to now is as follows: If IFRA is 4%, I put in 4%, then I add 2% of anything else that has IFRA of 6% or more. But, this doesn't seem to consider the specific bad actor in FO #1. If FO #2 also has the same bad actor, then it seems like I would exceed IFRA.

You are correct; you calculated your fragrance based on IFRA on the total oils and then added a second fragrance oil without considering if it had any of the same components that caused the first fragrance to be limited to 4%.

My suggestion prevents that because you are doing a calculation for a specific amount of oils and then doing a separate calculation on FO 2 for a specific amount of oils just as if you were making two batches of soap. This means that for half of the oils you were calculating at 4% if that is IFRA; and then for half of the oils you are calculating at 6% if IFRA more than that. When combined the batch will be fragranced with less than 6% fragrance. I used one-half but it could be 12 oz oils for FO1 and 30 oz for FO2. Still, you are doing the same type of calculation as if you were making 2 separate batches of soap each with a separated fragrance and then combining them for the one batch.

It is possible that if you did the work with the EU allergen sheets you might be able to use more of one of the fragrances, but I feel comfortable with my method that you won't be using too much fragrance.

 

[akseattle]

@lucycat , I can't say that I actually understand the reasoning or rational behind your method, but it is at least doable.
I looked up the EU Allergen sheets on 3 or 4 FO's . I had no idea what any of it meant. So, I do have a few FO's with low IFRA ratings. Not everyone likes an overly fragant bar (although I'm finding that most people do!! ), so I could use those fragrances and give them to friends or family that like low fragrance (again, not too many out there... ). So, if I get inspired, I might try your method.

What do others think? Does @lucycat 's method seem reasonable?