How to Make Bath Bombs

Bath bombs are easy and fun to make.  The process is so simple even young children can do it (with adult supervision, perhaps).  Nevertheless, bath bombs are a fun project and many people are now selling them on  online craft marketplaces such as Pinterest,  Etsy and many others.  With a little practice, bath bombs and hand-crafted soap can provide you with a nice little additional side income.  If you don’t feel entrepeneurial, bath bombs make great inexpensive gifts.

If you search online, you will find several recipes and instructional videos.  I encourage you to try any recipe you feel drawn to.  I will list a few here and make a few suggestions about how you can improve on  recipes that are widely used. It is my belief that with the right ingredients, you can make a bath bomb that stands out.

Ingredients Commonly Used

As you survey online bath bomb recipes, you will find that they contain some of the following items:  Citric Acid, Sodium Bicarbonate (Baking Soda), Epsom Salt, starch (usually corn starch), Borax, an oil (olive oil, mineral oil, coconut oil), essential oil or fragrance oil, and maybe also witch hazel, food coloring or soap coloring, micas, flower petals and herbs.

Ingredients less Commonly Used

Less commonly used ingredients include: Sodium Lauryl Sulfoacetate, Polysorbate 80, Glycerine

Before we talk about ingredient proportions and specific recipes, let’s examine these ingredients in detail.

Basic Ingredients

Every recipe will contain Citric Acid and Sodium Bicarbonate. The presence of these two items in water is what creates the fizzy reaction that fascinates people.  If it were possible to compress only these two ingredients so that they held a solid shape, that would be sufficient to make a working bath bomb.

Fillers

In my book, when you find Borax and/or  Epsom Salt in a bath bomb, they are really nothing more than fillers.  The rationale of using Epsom salt is that people take baths in Epsom Salt to relax. But think about it: how much Epsom salt can you fit into a bath bomb? Maybe a tablespoon? So how much will that enhance your bath experience? Not very much.  What about Borax? Borax is basically a laundry detergent booster.  It might make the water softer but does not have any foaming or bubbling properties.

It is debatable whether or not starch is a filler or if it has a greater purpose in bath bombs. Since most people rely on using a small amount of moisture to pack and form the material in a mold, it can be argued that the starch holds the moisture and holds the whole thing together. It is also thought the starch holds the essential oils.

Scents

Either essential oils or fragrance may be used may  to provide a scent to your bath bomb.  Essential oils are usually more expensive, but people who love essential oils wouldn’t settle for less.  The advantage of fragrance oils is that you can cheaply buy  an oil that has a blend of aromas, which may be too costly to produce by blending several essential oils.

Coloring Agents

Coloring agents include soap coloring, food dye and micas. Micas are very small colored powders.  With micas, you can make beautiful looking bath bombs. The only trouble is that mica residue may remain on your bath tub. Or, if it is on your skin, can end up coloring your towel.

Aesthetic Extras

Rose petals, herbs and similar items are sometimes thrown in just for the sake of making the bomb more attractive or interesting

Four Bath Bomb Recipes

I found the following 4 recipes online.  After listing them, I will suggest a few improvements.

Recipe 1

  • 1 cup baking soda
  • 1/2 cup citric acid
  • 1/2 cup Epsom salts
  • 1 tsp. water
  • 2 tsp. essential oil
  • 3 tsp. oil (olive oil)
  • food coloring (any color you want)

Recipe 2

  • 4 oz. baking soda
    2 oz. corn starch
    2 oz. citric acid
    2 oz. Epsom salt
    1 to 1 1/2 teaspoons water
    1 teaspoon essential oil
    1 1/4 teaspoon oil (I like coconut or olive oil here)
    1-2 drops food coloring (optional)

Recipe 3

Recipe 4

Discussion: In the first 3 recipes, we find  a 2 parts Baking Soda to 1 part Citric Acid ratio.  The last recipe has a 1:1 ratio of these 2 ingredients.  The best ratio should be closer to 1:1, though not exactly that.  A further problem is that the first, second and fourth recipes are measuring by volume, rather than weight.  For best results, I recommend measuring the ingredients in grams.  The best formula, I believe, should be 46% Citric Acid to 54% Baking Soda.  By using grams, you would simply measude out 46grams of Citric Acid and 54 grams of Baking Soda (before adding other ingredienrs such as SLSA).  A 100 gram bath bomb might be a little small.  If you want a bigger one, then double the recipe. You can mix a large batch of material for making several bath bombs by measuring out 1000 grams of material ( 460 grams Citric Acid with 540 grams of Baking Soda).  To increase the bubbles and foam, I recommend adding a surfactant such as Sodium Lauryl Sulfoacetate (SLSA).  I have also heard that adding Polysorbate 80 will also produce more foam if you have oil in your bomb.  If you want top spend a lot of money to make the perfect bath bomb, you might buy Natrasorb Bath Starch which is sold here.  Personally, I think it is too expensive. But if you read the product description you will see it is supposed to be a “modified tapioca starch.”  Try out regular tapioca starch and compare it with corn starch to see if it is any better.  I think  maybe the best oil to use would be the coconut oil that is solid at room temperature.  You may also consider using Glycerin as a wetting agent and skin moisturizer

Final Recipe and Instructions

Needed Ingredients: Sodium Bicarbonate (Baking Soda), Citric Acid, Sodium Lauryl Sulacetate (SLSA), starch, fragrance oil, coconut oil, food color, molds, mixing bowls, 2 small spray bottles.

54 grams Citric Acid

46 Grams Baking Soda

40 grams Starch (Tapioca or Corn)

40 grams SLSA

Coconut Oil

Water

Food Coloring

Instructions: in one large bowl mix together the Citric Acid, Baking Soda and SLSA.

In a separate bowl put your starch. Mix the food coloring with water and but it in a small spray bottle.  Spray the starch to color it.  Be careful not to make it too wet. Mix it around. Now spray it with the spray bottle that contains your fragrance. Mix the starch again.

Take 2 tablespoons of coconut oil and, using your hands, mix it into your mixture of Citric Acid, Baking Soda and SLSA.  Add your colored, scented starch and mix with your hands. When it is well-mixed, pack it into molds.  Allow to dry out for 1-2 days before use.