Whisk together all the dry ingredients.

Add the oil and water to the dry mixture while stirring briskly. This is especially important while adding the water, as it creates a fizzing reaction. Start with ¾ teaspoon and only add more if the bath bomb mixture is not holding a clump when a handful is squeezed in your hand.

Fill each half of a bath bomb mold, gently pack and overfill each half then press firmly together to create each coffee bath bomb.

Set aside to let the bath bombs air dry. Lower humidity days are ideal.

Once the coffee bath bombs are dry, package them in an airtight container or plastic bags for later use or gifts.