Bath Bomb Formulation Advice

Thank you for your question regarding your bath bomb formulation. Based on your proposed ingredients and questions, along with the staff's helpful initial response, here is some advice:

• AminoWash (Sodium Lauroyl Glutamate): You asked whether to use fine or coarse powder. The staff recommended using the coarse powder type for bath bombs. This is because the coarser texture can contribute to a better feel in the finished bath bomb and may assist with binding and pressing the mixture into shape.

• Fragrance: As the staff correctly advised, you should use fragrance oils designed for cosmetic use, not food flavors. To incorporate the fragrance into your dry mix without triggering the fizz reaction, it's best to first mix the fragrance oil with a small amount of a liquid carrier oil (like Sweet Almond Oil or Jojoba Oil) or a solubilizer such as Polysorbate 80. Then, slowly add this liquid mixture to your dry ingredients while continuously mixing. Spraying is a good technique for even distribution.

• Color:

  • Suitable Types: For bath bombs, pigments like Mica powder, Iron Oxides, and Lake Pigments are generally preferred. These colors disperse in water rather than fully dissolving, which helps prevent the color from fading over time, a potential issue with some water-soluble dyes as noted by the staff.
  • Natural Colors (Gardenia Blue Pigment): You specifically asked about Gardenia Blue Pigment. This is a natural pigment powder. However, according to its description, it is water-soluble. While it can be used, be aware that water-soluble colors like this might be prone to fading in a bath bomb over time, as the staff mentioned.
  • Using Powder Color: Do not dissolve powder colors (especially pigments) in water before adding them to your main dry mix, as this will start the fizz reaction prematurely. Mix powder colors directly with your dry ingredients (Sodium Bicarbonate, Citric Acid, etc.) to ensure they are evenly distributed throughout the powder blend before you add any liquid binder.

• Corn Starch: Corn starch is not strictly essential but is a very common ingredient in bath bomb formulations. As the staff explained, it acts as a binder, helping the mixture hold its shape when molded or pressed. It can also help to slow down the reaction between the citric acid and sodium bicarbonate slightly, resulting in a longer-lasting fizz. If you choose to include it, a typical usage rate is around 5-10% of the total formula. Standard corn starch is usually used for binding; modified starches like CornThick may behave differently.

• Other Ingredients: You can enhance your bath bomb by adding other ingredients:

  • Carrier Oils/Butters: Adding a small percentage (e.g., 3-10%) of moisturizing oils or butters like Shea Butter, Cocoa Butter, or Coconut Oil can leave the skin feeling soft. Carefully mix melted butter or liquid oil with the dry ingredients.
  • Emulsifiers: When using oils, adding an emulsifier like Polysorbate 80 (around 1-5%) is highly recommended. It helps the oils disperse into the bath water rather than sitting on top, preventing a slippery tub and ensuring colors and oils are distributed evenly.
  • Salts: Epsom salt or Dead Sea salt can be added for their therapeutic properties.
  • Clays: Cosmetic clays like Kaolin clay can improve binding and texture.
  • Botanicals: Dried flower petals or herbs can be added for visual appeal, ensuring they are safe for bath use.

Remember to mix all dry ingredients thoroughly before gradually adding your liquid ingredients (fragrance/oil mixture, and any binder liquid like witch hazel or alcohol, if used) just until the mixture holds together when squeezed, but is not wet enough to fizz. Then, quickly press into molds.