# Essential oil ratio in bath bombs



## NOLAGal (Mar 23, 2017)

Is 3-5 drops of essential oil for every 1 tbsp of carrier oil a good ratio to use? I'm looking for the strongest smell but that is at a safe level.

I've googled this for hours, everything I come across talks about ratios for soap, which I would imagine would be drastically different for bath bombs. I can't find any ratios for essential oils or fragrance oils in bath bombs. 

Then I come across formulas like this:

1 cups Sodium Bicarbonate (baking soda)
3/4 cups Citric Acid
1/4 cup Dead Sea Salts
60 drops of Lavender Essential Oil

That just seems like a lot of essential oil for such a small amount of mixture. 

I don't want to add too much that would cause skin irration but would like to have a great strong smell not something weak.

Can anyone point me in the right direction or a good source I can use to educate myself more? Thanks!


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## Zany_in_CO (Mar 23, 2017)

The thing about using EOs is that the rate of use depends on which EO you're using. It's different for each one --  i.e., you can use more lavender (mild) than clove or cinnamon (highly sensitizing). Majestic Mountain Sage has a "fragrance calc" for various products. Enter the product, the amount, and then use the drop down menu to select from a list of EOs and FOs to get the amount needed for the amount of product you're making. 

www.thesage.com

Here's a conversion table for drops / mls/ teaspoons / tablespoons / ounces


> 20 drops     1 ml
> 40 drops         2 ml
> 60 drops         3 ml
> 80 drops         4 ml
> ...


If t'were me, I'd find a few recipes for bath bombs that are fragranced with EOs and use that as a guide. Make sense?

HTH   :bunny:​


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## Millie (Mar 23, 2017)

I wonder if you'd have better luck searching for usage rates for bath salts and bath oils. I think whatever amount of EO or FO is used for one bath could be the same for a bath bomb, because it will be diluted by a tub of water.


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## LilyJo (Mar 24, 2017)

Just had a look at what a well known safety assessor recommends in the UK and the maximum approved rate for the use of EO in bath bombs is 2% but with limitations down to 0.1% for some of the more irritant or potent oils.


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## Dahila (Mar 24, 2017)

that conversion table is not good, most essential oils  are 1 ml =0.9 g
Serious cosmetic crafters do not use teaspoons to measure, they always use weight


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## NOLAGal (Mar 24, 2017)

LilyJo said:


> Just had a look at what a well known safety assessor recommends in the UK and the maximum approved rate for the use of EO in bath bombs is 2% but with limitations down to 0.1% for some of the more irritant or potent oils.





Is that 2% of all ingredients or just the wet ones? Thanks!

I am researching and learning which are mild and which can cause irritation. Also learning about notes.


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## Zany_in_CO (Mar 24, 2017)

Millie said:


> I wonder if you'd have better luck searching for usage rates for bath salts and bath oils. I think whatever amount of EO or FO is used for one bath could be the same for a bath bomb, because it will be diluted by a tub of water.


Makes sense to me, Millie! MMS Fragrance Calc has bath salts and bath oils on the drop-down menu for product choice:

https://www.thesage.com/calcs/FragCalc.html


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## LilyJo (Mar 24, 2017)

NOLAGal said:


> Is that 2% of all ingredients or just the wet ones? Thanks!
> 
> I am researching and learning which are mild and which can cause irritation. Also learning about notes.



Pretty sure its max 2% of all ingredients - thats the way I read it and the way I have calculated mine previously.


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## NOLAGal (Mar 24, 2017)

Zany_in_CO said:


> The thing about using EOs is that the rate of use depends on which EO you're using. It's different for each one --  i.e., you can use more lavender (mild) than clove or cinnamon (highly sensitizing). Majestic Mountain Sage has a "fragrance calc" for various products. Enter the product, the amount, and then use the drop down menu to select from a list of EOs and FOs to get the amount needed for the amount of product you're making.
> 
> www.thesage.com
> 
> ...



Thanks You!  The calculator there works great.  I selected "bath salts" as a few people suggested that it would be the same for bath bombs as well.  I also use ml for my wet ingredients and ounces for my dry, so this will be easy for me to follow.


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## NOLAGal (Mar 24, 2017)

Dahila said:


> that conversion table is not good, most essential oils  are 1 ml =0.9 g
> Serious cosmetic crafters do not use teaspoons to measure, they always use weight



My teaspoons and tablespoons also have the equivalent ml for each, so I keep track of my wet ingredients by total ml and use the measuring spoons to get my amount. I use ounces for the dry and use a digital scale.


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## SaltedFig (Mar 25, 2017)

Dahila said:


> that conversion table is not good, most essential oils  are 1 ml =0.9 g
> Serious cosmetic crafters do not use teaspoons to measure, they always use weight



Today it is a bit hot here for soaping (my coconut was clear liquid). Yesterday it wasn't so hot when I soaped.

Yesterday 30 drops of an essential oil was 1.40 grams.
Today the same essential oil took 25 drops to reach 1.43 grams.

I knew drop weight varies with oil and ambient temperature, but the actual difference surprised me.


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## Dahila (Mar 25, 2017)

wow, so the temps would change the weight?  I never use tsp always weight, so no idea , but I do know that size of drops is not the same from every dropper, that much I can see when I weight them 
Did you use the same dropper yesterday as today?


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## kchaystack (Mar 25, 2017)

Dahila said:


> wow, so the temps would change the weight?  I never use tsp always weight, so no idea , but I do know that size of drops is not the same from every dropper, that much I can see when I weight them
> Did you use the same dropper yesterday as today?



It changes the density, which effects its volume.  So the weight of the same volume of a cool substance is usually more than a warm substance.  

That is why we always weight ingredients.


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## Dahila (Mar 25, 2017)

kchaystack said:


> It changes the density, which effects its volume.  So the weight of the same volume of a cool substance is usually more than a warm substance.
> 
> That is why we always weight ingredients.



that exactly my point too :bunny:


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## SaltedFig (Mar 26, 2017)

Dahila said:


> wow, so the temps would change the weight?  I never use tsp always weight, so no idea , but I do know that size of drops is not the same from every dropper, that much I can see when I weight them
> Did you use the same dropper yesterday as today?



Yes, I used the same batch of essential oil and the same dropper.

The temperature difference was about 10C (so about 50F difference).

My oil drops also vary according to the viscosity of the oil itself (so  my eucalyptus is much "thinner" than my cedarwood essential oils) - I haven't measured the difference to check for sure, but I think the drops of thinner oils are smaller/lighter as well.


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## Dahila (Mar 26, 2017)

Salted Fig weight is weight does not matter of temps,  1 g oil weights 1 g oil.  It is a nonsense , I am sorry I am not playing this game anymore.......


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## SaltedFig (Apr 5, 2017)

Dahila said:


> Salted Fig weight is weight does not matter of temps,  1 g oil weights 1 g oil.  It is a nonsense , I am sorry I am not playing this game anymore.......



 Sorry to have left this so long Dahlia. I had not come back to read this topic until now.

My point was the same as yours (which is why I quoted you – because I agreed).   

I used my recent example of how the weight (measured accurately in grams) of a given volume (counting drops) could vary with temperature as an example of WHY I agreed with you.

I apologise for having so poorly described my original agreement.

This is my agreement in blunt form:

1. Inaccurate measuring can be dangerous in chemistry.   

2. Measuring an ingredient by volume is not accurate.
      - Any tables based on volume measurement will have built-in inaccuracies.
    - Volume-based inaccuracies compound as the volume increases.  

  3. Measuring by weight is accurate.


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## Dahila (Apr 5, 2017)

Agree  :headbanging: when I see tbsp's and cups


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## Thornandthimble (May 15, 2017)

This is also kind of misleading and I've been confused regarding EO's too. Because you're putting a bomb in an entire tub of water, so doesn't that dilute the EO enough that it would have very little risk? I mean 5 drops of EO in a tub of water is less than 2%... Or is it really that it needs to be 2% or less than the product? Because close contact like a lotion or soap is different than the substantial dilution of a bath, right?


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## LilyJo (May 16, 2017)

As far as I know it needs to be 2% of the actual product - you cant ever know the size of someone bath or bowl or how they would use it which is why the maximun percentage is designed to be skin safe.


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## Thornandthimble (May 16, 2017)

Gotcha. That makes sense! I used the calculator and the 2% is actually more than  I thought volume-wise. Safety first!


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