What causes fizzing in bath bombs?

 Oct 11,2022

Bath bombs' primary ingredients are a weak acid and a bicarbonate base. When they’re added to the warm water in your tub, the bomb starts to dissolve into multi-colored bubbles, and fizzy swirls throughout the water. That’s thanks to two other key ingredients: baking soda and citric acid. This is an acid-base reaction that involves the conversion of citric acid and sodium bicarbonate to monosodium citrate and carbon dioxide:

C₅H₇O₅CO₂H _(aq.) + NaHCO_{3 (aq.)} → C₅H₇O₅CO₂⁻Na⁺_(aq.) + H₂O_(l) + CO_{2 (g)}

Bath bombs start to fizz when water triggers a reaction between citric acid and a “neutralizing substance” like baking soda or sodium bicarbonate. While dry, the chemicals in citric acid and baking soda are stable. But when water is added to the mix, citric acid and baking soda react together to produce carbon dioxide bubbles. That’s the fizz! This carbon dioxide reaction breaks the bath bomb apart, releasing its intoxicating fragrances and oils.

While baking soda and citric acid react almost instantly to water, that doesn’t mean the fizzing only happens when you drop bath bombs in the tub! Most bath bombs will fizz in hot water for about six to eight minutes. Even after it dissolves, you will still be able to feel the fizz of the carbon dioxide bubbles for a bit. Think of it as an ongoing massage right in your tub!

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UNITS: US

1 1⁄2cups bicarbonate of soda (baking soda)

1⁄2cup citric acid, powder

2teaspoons sweet almond oil

essential oil (or fragrance)

food coloring

First, you need to make the base mix. To do this, sift together the bicarb soda and citric acid in a large dry bowl.

Transfer 1/2 cup AT A TIME to another dry bowl; add any dried flowers, glitter, etc.

Set aside.

In a small bowl, mix together 1/2 teaspoon AT A TIME of almond oil, 6- 8 drops of your chosen essential oil& 6 drops of food coloring.

Pour the oil mixture into the 1/2 cup of base mix& mix QUICKLY before it starts to fizz!

Combine with your fingertips until all color is evenly distributed.

Wipe a little sweet almond oil inside your molds.

Fill the molds with the mixture, packing it in firmly.

Repeat this process with 1/2 a cup at a time, using different fragrance/color blends if you wish.

Leave the bath bombs to set for 24- 36 hours.

When set lightly, tap the mold & ease out gently.

*Hot water activates the fizzy bath bombs much better than cold water!

Follow the four-step guide below, and you'll be on your way to luxurious relaxation.
Step by step
1. Fill your tub with water that's comfortable to the touch. You should be able to dip your hand into the water and leave it there comfortably for up to 10 seconds.
2. Don't fill your tub straight to the top—you could lose some of your beautiful bath bomb water when you get in.
3. Drop in the handmade bath bomb of your dreams and enjoy the show. Some have hidden sparkle, a blend of colors, gorgeous fragrances, and more. Watch the magic unfold.
4. Get in and enjoy! Now's the perfect time to kick back, throw on a mask, put on a podcast, and take some time for yourself.