Help – Oils and Water Don’t Mix. Right?


I am so confused.

It began as an attempt to make the perfect bath bomb as a home school science experiment. Two of my kids and I were trying to figure out what ingredients we could use that would:

  1. Make the perfect balance of acid and base and hence a great FIZZZZ.
  2. Be a good balance of powder and liquid
  3. Include therapeutic properties
  4. Ultimately disperse essential oils in water,  safely

Acid versus base tests

We decided to start by testing acid versus base. We chose things like witch hazel, buttermilk powder, citric acid,  milk powder, alcohol, castile soap, epsom salt, baking soda, green tea, and ground ginger ….. Using a home made (boiled purple cabbage hijacked experiment from YouTube) indicator we poured a bit into the variables and saw immediate results. Red liquid was an acid, purple neutral and blues and greens a base. Citric acid > red-acid, baking soda > blue-base, all essential oils (one from each chemical functional family)> purple – neutral, teas interestingly green-base, cream of tartar – hot pink-acid, and heaven knows why – hydrogen peroxide more clear – but maybe yellowish.

We then went on to investigate what we could use to best disperse the oils in water. After-all essential oils are defined as an oil not because they are greasy but because they DON’T mix with water. Who wants an oils slick on top of the water when one’s bod is in the bath?

We put three drops of german chamomile (from a company who posts GC/MS reports and passed third party testing {BTA} of other oils) with 1/8 cup water and 1/8 t of our variables. We had one control with just water. German chamomile was chosen because it’s blue color is easy to observe. They were stirred with clean chopsticks and shaken for 20 seconds. Containers are PET (problems with plastic use are long-term use and undiluted oils, from my understanding).

My original course work suggested using a little bit of vegetable oil with the essential oil as a dispersant. I had also seen some fun experiments showing that castile soap did a good job of dispersing. I know the additives polysorbate and Solubol can help – but have been looking to use more common ingredients. I have always added a bit of grapeseed oil to my aromatherapy bathsalts and experimented with the castile soap (which I NOW know cande-saponify {new Scrabble word} when used with epsom salt – floating gummies in one’s bath is icky > taking THAT mistake as a learning opportunity.)

Of course alcohol (80 proof or rubbing) is a great one for mixing oils into cleaners but I don’t want alcohol, really, in my bath to dry my skin unless it comes in the form of a nice glass of Cabernet.

Here is where it got confusing, counter-intuitive, and opposite of anything I have seen. The order from BEST to Worst (using our EXACT homemade measurement system: size of ring of oils resting on top doing their defined job of not mixing with water):


Water, glycerin, rubbing alcohol


  • BEST – plain old tap water
  • Glycerin
  • Rubbing alcohol
  • Vodka
  • Epsom Salt
  • Sea Salt
  • Grapeseed Oil
  • Non-fat powdered milk
  • Powdered buttermilk
  • Worst – Castile soap

I am perplexed as I would have thought the results would have been somewhat flipped. We guessed  that buttermilk would have been best, followed by castile soap, then the booze … water worst.

Tap water

Tap water

Castile Soap

Castile Soap

The first thing that came to mind was operator error. But it was pretty basic …. we used a small measured dropper for the chamomile and measuring spoons and cups. Not everything was Mayo Clinic strict (including picture taking – not sure where vodka went). For a home-kitchen table project, the kids did great.

Then we considered water. Water is H20 but it can be so different depending on where you live, how it is processed, hard or soft, flouridated, or if you are on a well – filtered or not. A gazillion variables.

And of course, a good scientist when faced with surprising results – considers them as potentially revealing something new and try to do it all again (replicate). After-all, our goal was not to confirm our current beliefs but to find out what in fact works best.Even if we are a sorry group of scientists, that is a super lesson about surprise and expectations and  REALLY fun.

Before we do try to do this again … wondering if you could help us….

What do you think went on here or what do you think was revealed? What could we learn or ask in another way? Could essential oils disperse just fine in tap water from Snoqualmie, Washington?

We are off to finding the best bath bombs EVER! However, our 2nd attempt ended with awesome functional bombs but not so aesthetic. They look like falafel or donut holes. We have the usual suspects of baking soda and citric acid but also buttermilk, glycerin, PINK Himalayan sea salt, RED Hawaiian salt, Chamomile tea, Vitamin C oil and dried Melissa leaves (lemon balm) from my garden (with essential oils of copaiba, lavender, and grapefruit). Not for sale just for play. They are hard and fizz, but um … ugly. Considering it victory, nonetheless.


Disclaimer: Not suggesting pouring oils directly in a bath. In the Words of Ms. Frizzle we are “Asking questions, taking chances, making mistakes and getting messy”



(Please don’t judge: the clutter, dog hairs, nor amateur photography. Feel free to admire the kids.)