Whether you’re looking for stress relief or some alone time after hanging out with your family, there are many reasons why you can’t get enough of your tub this winter. But one variable to consider the next time you take a much-needed bath: would your bath be better with a bath bomb?

If you’re new to the bathroom-related self-care routine, bath bombs are little pucks with scented and salt on them. They bubble up and turn dips into a multi-sensory experience. While you can buy bath bombs from major cosmetic retailers, you don’t always know what is in them. And when it comes to potential allergens, “there are no bath bombs that are completely risk-free,” said Hadley King, a dermatologist from New York City.

However, making them at home gives you control over the ingredients list, said Jovana Ristić, the author of the beauty blog Be Spotted, which focuses on DIY beauty products. Or, you may already have most of the ingredients in your pantry.

While the do-it-yourself approach allows you to avoid irritants, it also allows you to add beneficial ingredients. Ms. Ristić’s recipe for bath bombs contains colloidal oatmeal, which is known for its skin-soothing properties, said Dr. King. Shea butter is also used, which can help moisturize the skin.

Most bath bombs are based on the same base: Epsom salt, baking soda, and citric acid. The soda and acid cause the bubbly, and when used together they should cancel each other out when it comes to changing the pH of your bathing water, which means it is neither too acidic nor too alkaline, said Dr. King. This is worrying as a significant change in the pH of your bath water can lead to vaginal irritation or yeast infections.

If you have sensitive skin, mend the test ingredients by applying a small amount to your forearm. Let it sit for 15 minutes, then rinse it off and see if you’ve developed a reaction in 48 hours, said Dr. King. (Essential oils are especially important to test because they’re the most likely irritants, she said.) To be on the safe side, don’t soak with a bath bomb for more than 15 minutes and rinse off when you’re done.

This recipe, courtesy of Ms. Ristic, takes some practice. To get the bombs to the right consistency, they should be wet enough to hold together but not so wet that they start to hiss in the mold. The good news is that even badly shaped bath bombs gush and smell great. So don’t sweat if yours don’t look in-store on your first try.

¼ cup of colloidal oatmeal flour (You can also use ¼ cup of oatmeal flour, which is pulsed in a food processor until it is finely ground.)

½ cup of Epsom salt

½ cup citric acid

1 cup of baking soda

2 tablespoons of shea butter, melted (you can use other oils such as coconut or almond oil)

20 drops of the essential oil of your choice

Water in a spray bottle

You will need a mixing bowl and some type of mold. A meatball, ice cream, or cookie scoop will work. Amazon also sells custom-made molds. You should also wear rubber or latex gloves, as citric acid can irritate the skin if not diluted with water.

Mix the dry ingredients in a medium bowl. Add the melted shea butter and essential oil and mix to combine. Sprinkle the mixture with some water and fill the forms. With your gloves on, slide the mixture into the molds. It should be just wet enough that when you squeeze it, it clumps together. Let it sit for a minute or two before tapping the mold to loosen it. Allow the final products to dry for at least two hours before use.