Bath bombs usually are easy to make, but they can also be finnicky and frustrating. It takes some trial and error to find a recipe that works perfectly. Most problems with bath bombs come down to the ratio between wet and dry ingredients.
If your recipe turns out slightly too wet, the fizzing action might start prematurely and result in your bath bombs expanding out of the mold. Too dry, and you can get crumbly bath bombs that break apart and don’t fizz properly. If you’re struggling to make your bath bombs turn out right, we’ve got a few tips that might help.
1. Keep ratios in mind. Regardless of the end result, most bath bomb recipes use the same basic ratio of 2 parts baking soda and 1 part citric acid. Baking soda and citric acid are the ingredients that react together in water to create fizz. As long as you stick to that basic 2:1 ratio of baking soda to citric acid, you should still get a nice fizzy bath bomb even if you use additional dry ingredients. Just be careful not to add too much when it comes to other dry ingredients. For example, additives like corn starch, kaolin clay or Epsom salt are all common ingredients, but most recipes only call for a small amount.
2. Be conscious of wet ingredients. The fun part about making bath bombs is that there are countless recipes and ingredients to try. But this can also be the frustrating part. Any time you add oils, butters or even fragrance oils to your bath bomb recipes, you’ll need to consider how it will affect the final consistency. Any one of these ingredients can result in a mixture that’s too wet and doesn’t perform well.
It’s a good idea to use oils sparingly. In most recipes, you should add no more than 1 tablespoon of oil per cup of dry ingredients. If you want to experiment with more than one type of oil, or a combination of fragrance and other oils, keep the liquid ratios in mind.
Also remember that ingredients like coconut oil or shea butter can make your tub slippery. If you use oils, it's important to include a warning label before giving bath bombs as a gift.
3. Use witch hazel instead of water. Some bath bomb recipes call for water, but keep in mind that water is what causes baking soda and citric acid to react and create fizz. You want to keep the fizzing action to a minimum when making your recipe, or else your finished product won’t perform well. Instead of water, try using witch hazel.
When you add witch hazel into your mixture, you’re only adding a tiny amount at a time. It works great to put your witch hazel in a spray bottle rather than pouring it or using a dropper to add it to your dry ingredients. That makes it easier to get the perfect consistency without going overboard on liquids.
4. Stir constantly while you add liquid ingredients. Once your dry ingredients are mixed, we recommend adding your wet ingredients like fragrance, polysorbate 80 and any oils next. These wet ingredients shouldn’t cause a fizzing reaction, but it’s still helpful to mix them completely as soon as they’re added. Once other wet ingredients are incorporated, begin spritzing with witch hazel until you get the right consistency.
Even though witch hazel causes less of a reaction than water, a small amount of fizzing will likely occur. After each spray, compress the mixture right away to prevent fizzing. It works well to spritz with one hand while simultaneously compressing and mixing with the other hand until you get a consistency that resembles damp sand. The mixture is ready when you can compress it into a solid form that still crumbles when crushed.
5. Avoid food coloring. A lot of DIY bath bomb recipes will tell you to color your fizzies with food coloring. However, this can stain your tub. Instead of food coloring, we recommend water-soluble colorants such as mica powder. Of course, any colorant can cause staining if you use too much, so don’t go overboard with mica. Thankfully, a small amount of mica goes a long way in bath bombs, and all of our micas are skin-safe, cosmetic-grade colorants.
6. Use polysorbate 80 when making colored bath bombs. For even better results with mica in your bath bombs, you can try adding polysorbate 80 to your recipe. This ingredient helps mica colors disperse better, while also keeping pigments from sticking to your tub. Even with polysorbate 80, it’s a good idea to wipe down the tub after using a bath bomb to remove any residue that may be left over. Keep in mind polysorbate 80 is a liquid ingredient, and therefore can affect the consistency of your recipe.
7. Kaolin clay helps harden bath bombs. Struggling with soft bath bombs? Try adding a little bit of kaolin clay. This ingredient makes bath fizzies more durable while also helping them to hold their shape. For best results, use about 1 tsp of kaolin clay per cup of dry ingredients.
8. Sift or blend your dry ingredients for better results. If there are lumps in any of your dry ingredients, you might end up with lumpy looking bath bombs. To avoid this, try sifting all of your dry ingredients as you add them to your mixing bowl. Another technique is to use a small blender to mix your dry ingredients. Blending your dry ingredients for 10-30 seconds will ensure that all of your ingredients are completely mixed.
9. Mix with your hands. Some people like to stir their bath bomb ingredients with a spoon or use a standing mixer. However, mixing with your hands makes it easier to tell when you’ve reached the right consistency. Wearing gloves, simply knead the mixture as you add your wet ingredients. As an added benefit, this method allows you to break up any rogue clumps in your dry ingredients.
10. Disperse mica for better results. Because mica is powdered, you can add it with all of your other dry ingredients. However, it’s hard to tell if you’ve added the right amount of mica when it’s blended with just the dry ingredients. You won’t be able to tell how intense your color is until you add wet ingredients that start dissolving the pigments in the mica.
An easy solution: Use a container such as a 1oz measuring cup to stir your mica into any wet ingredients you’re using. For example, if you’re using fragrance oil and polysorbate 80, you can add these to your measuring cup and stir your mica powder into the liquid. This helps the mica disperse, and makes it slightly easier to blend into your mixture.