Mix together epson salt, baking soda, citric acid, and cornstarch in a large bowl.
Slowly add the coconut oil, essential oil, and food colouring to the dry mixture. This has to be done slowly so the baking soda does not start to bubble.
Once the above is mixed, slowly add your water. Add small amounts at a time, mixing with your hands during the breaks. The mixture is ready once you can form it without it falling apart.
Once mixed, add the ingredients to your bath bomb forms. For these bath bombs, I used clear plastic Christmas ornaments but you can really use anything you would like!
Let dry overnight. Once dry, you can remove them from their forms and use however you would like :). I individually wrapped these for gifts by taking a small square of parchment paper and tieing together with twine.
You can use any food colouring colour you wish. For this recipe, I used 5 drops of red food colouring. You can add more or less just depending on how intense you would like the colour.
Be sure to add wet ingredients slowly to prevent activating the baking soda. However, do not be alarmed with some minor fizzing! :)