Measuring, Blending, Math Help!

[Nikkor]

I received my EO's and have come up with a blend I'd like to try in CP soap. As usual I have some questions.

Let's say I want to make a blend of 5 parts Lavender, 4 parts Rosemary & 3 parts Cedar. I measure in teaspoons all parts and combine in a glass bottle.

Now I want to make 1 pound of CP soap and use .5 ounce of EO per pound. I would then just measure a .5 ounce of the blend to add to the soap at trace.

Is my thinking correct or am I missing something?

Would the "blend" I measured in the bottle be stable to store for a period of time or do the different EO's react badly blended? If that's a problem do you experienced soapers measure/weigh out each individual EO and mix every time you make a batch of soap? If that's the case then what would be the mathematical equation to use? For example with my 5-4-3 parts blend above, how do I figure out the right percentage for each EO to achieve my .5 ounce?

Any helpful tips on measuring/blending would be great.

 

[Nevada]

add up the parts 5+4+3=12
Target Percentage is .5/16 = 3.125%
divide by 12 = .26%
multiply 5 pt Lav x .26% = 1.3%
Multiply 4 pt Rose x .26% = 1.04%
Multiply 3 pt Cedar x .26% = .78%
Check by adding 1.3% + 1.04% + .78%= 3.12%
Hoped this Helped
Roy

 

[Nikkor]

add up the parts 5+4+3=12
Target Percentage is .5/16 = 3.125%
divide by 12 = .26%
multiply 5 pt Lav x .26% = 1.3%
Multiply 4 pt Rose x .26% = 1.04%
Multiply 3 pt Cedar x .26% = .78%
Check by adding 1.3% + 1.04% + .78%= 3.12%
Hoped this Helped
Roy

I'm in awe of your outstanding math skills! I appreciate you taking the time to answer my question on finding the percentage(s) needed to achieve my desired weight. I do think I must have phrased that part of my query incorrectly as I can't see having to to use that mathematical formula for my purpose. There has to be a simpler way to achieve my goal. If not, I'm going to be upset with my decision to use EO's and not FO's!

 

[DeeAnna]

"...I would then just measure a .5 ounce of the blend to add to the soap at trace.

Is my thinking correct or am I missing something?..."

Yep, you're right on. Easy, right? Another benefit is that it's more accurate to make a blend like this -- your scent will be more consistent from batch to batch.

"...Would the "blend" I measured in the bottle be stable to store for a period of time or do the different EO's react badly blended?..."

It should be stable. That's how fragrance oils and essential oil blends are made.

"...5 parts Lavender, 4 parts Rosemary & 3 parts Cedar ... 0.5 oz blend..."

Here's how I would do it. Start the way Nevada did:

5 parts + 4 parts + 3 parts = 12 parts in the whole

Then use the parts to figure the weight directly:

0.5 oz / 12 parts = .041665 oz / 1 part

5 parts * 0.041665 oz = 0.208 oz
4 parts * 0.041665 oz = 0.167 oz
3 parts * 0.041665 oz = 0.125 oz

Check: Does 0.208 + 0.167 + 0.125 = 0.5? Yes.

Hint: Really consider getting a gram scale that weighs to 0.1 g accuracy. You'll be much happier weighing out these tiny amounts.

 

[Nikkor]

Thank you so very much DeeAnna! I must admit when I saw Nevada's reply my brain twisted like a pretzel in confusion. You have a way of patiently explaining all the difficult stuff that even I can understand. You really are a "SoaperStar"!

I used the EO blend formula you provided this morning on a 1lb batch of simple soap using oils of olive, palm, coconut and castor. No problems and the best part was I felt confident that my EO blend was measured correctly. It's in the mold and under the blanket, hopefully gelling as I write.

Thankfully I do have a very good scale that does weigh to 0.1g. It's the only quality piece of soaping equipment I have.

 

[DeeAnna]

I'm glad to hear that -- my soaping and lotion-making life got a lot easier when I got a scale like that too.

 

[soap_rat]

I'm such a cheapskate I cringe at losing EO to the measuring containers--also for some time I didn't know the chopstick/skewer trick to keep EOs from dribbling when poured--so I got glass syringes for measuring my EOs. I soap using grams, so when I calculate my scent I get the amount in grams. One gram of water= one cc or mL (the measurements on the syringe). EOs are almost all less dense than water, meaning 1mL of the EO is not one gram, but it's less, I'm not overusing the EO--and it's not much less.

The syringe (and the glass pipette I got for large volume) keep things really easy and tidy for me. It's easy to make up a blend in my storage bottle (once I know the recipe I want), shooting the EO through the syringe. And if I'm only using a small amount of an EO or blend at a time, the syringe is measured in tenths of a mL, very small amounts indeed.