Why Do My Bath Bombs Sink?

Why Do My Bath Bombs Sink
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Bath bombs entertain us better when they float right in front of our eyes. If they start to sink the experience we all opt-for is gone.

Plus, watching bath bombs fizz is a mesmerizing experience. And you know why:

It’s worth knowing that why do the bath bombs sink?

Reasons Why Bath Bombs Tend To Float

Before we begin it’s important to know how bath bombs float. What ingredients or manufacturing process contributes to its floating power?

table salt

At this point you might know that salt is one of the main ingredients bath bomb contains.

But, there is a lot of type of salts like:

  • Kosher salt
  • Epsom salt (this specific one is lavender scented which is perfect for you bath bomb)
  • Table salt
  • And more

The key is to use ingredients that have less bulk density then water and weight less in general. For example, if we compare the 3 salts listed above kosher salt is known to have less weight and thus it’s the perfect ingredient for bath bombs and qualifies for it.

The rule applies to other ingredients as well. For example cornstarch is better than cream of tartar. Cream of tartar makes the bath bombs sink while cornstarch helps bath bombs to float mainly because of their weights.

This is why knowing what ingredient makes bath bombs float? Is important as it gives you a map to follow and pick the right ingredients (if you’re making yourself). Also, you become more aware that you can spot the type of bath bomb (floating or sinking) by just looking at the ingredients list of it.

Shape Is A Considering Factor

Shape also plays a role in floating and sinking of a bath bomb. If a bath bomb has a flat bottom then it’s much easier for it to float while if a bath bomb bottom is round it’s difficult for a bath bomb to stay floated on the surface of the water.

That doesn’t mean round bath bombs don’t float.

But, generally and regardless of the materials used flat surfaced bath bombs easily float and don’t sink.

Are Bath Bombs Supposed To Sink?

Many people remain in misoncerpation and often ask:

Do bath bombs sink or float?

No, bath bombs are not supposed to sink. They should float and fizz right in front of your eyes and not deep under the bathtub.

Some people argue that bath bombs that tend to sink isn’t a bad thing which is correct if we’re talking about personal preference. And a few of the people think that if the bath bombs sink that’s the sign of quality because it’s naturally denser meaning large quantity of ingredients are used vs the lighter bath bombs.

It should be a personalized thing. Judging is not the solution in this case.

But, generally if the bath bombs float that means there’s a lot of science and ingredients picking goes in to making that bath bomb float.

Think about LUSH there bath bombs float on top as they pick the right ingredients and make bath bombs bubbly and lighter so it floats.

Sinking bath bomb isn’t a bad thing at all but what’s the reason when you can’t see the bath bomb fizz?


Knowing why do my bath bombs sink is important to understand so in your next bathing session you’ll be able to see the bath bomb fizz right in front of your eyes.

Watching bath bombs fizz is what makes bath bombs what they are. Beside other benefits like aroma therapy, skin benefits, betterment of mental health and stress relieve.

If they are fizzing inside the bath tub and not in front of the plain sight then that isn’t a lot of fun or is it?