How to make bath bombs fizz longer?

Are you tired of bath bombs fizzing out halfway through your soak? Do you want to make them last longer? You are not alone. This is a very common problem among bath bomb makers, but luckily, it’s not one that cannot be solved.

Bath bombs may fizz longer if you ad SLSA or cornstarch in your bath bomb mixture. A lower oil quantity and a denser bath bomb would also help. Changing the Citric acid and baking soda ratio (which is 2:1) and lastly, not using salts – especially Epsom salts will make your bath bomb fizz slower, thus for a longer period.

Discover the ‘secrets’ Professional Bath Bomb Makers use to create luscious bath bombs with this step-by-step guide. You’ll have a priceless reference collection of product recipes with natural ingredients designed to create a relaxing spa atmosphere in your own home.

You should never have to settle for less than perfection when making your bath bombs at home. With just a few simple tricks and tips, you can get rid of those pesky problems once and for all so that every single one of your baths turns into an unforgettable experience.

There are many reasons why bath bombs may fizzle too quickly, and most of the time, they can be easily fixed.  

Why is my bath bomb not fizzing?

If you see that your bath bomb is not fizzing how you’d like it to, there are three potential reasons why that’s happening.

  1. Low citric acid amount
    First, it can be due to a low quantity of citric acid. So, in these cases, increasing the amount of this ingredient in your recipe is the best thing to do. For instance, an excellent place to start is adding 1.5 parts of citric acid for every 2 parts of baking soda. This way, there will be a 2:15 ratio, making it easier for the bath bomb to “fizz.”
  1. Too much cornstarch
    Another reason why bath bombs don’t fizz as you’d expect them to is that you’ve used a large quantity of cornstarch. Multiple tests have found out that using too much cornstarch can reduce a bath bomb’s fizzing effect. So, if you’ve included this ingredient in your recipe, my advice is to decrease the quantity used or remove it altogether. In addition, using too much oil can also cause your bath bomb’s fizzing effect to decrease; hence, reducing the quantity can bring a greater effect.
  1. Moisture
    Furthermore, it is recommended to keep your bath bombs in enclosed environments where the air’s moisture or the room’s humidity can’t reach it. Otherwise, the fizzing reaction will be significantly reduced. 

If you don’t have an extra airlock Tupperware where you can store your bath bombs, try wrapping them in plastic as much as you can to prevent them from receiving harm from humidity. If you’d like some extra protection, perhaps using both of these methods can help you keep your bath bombs secure until you’re ready to use them.

What ingredient makes bath bombs fizz?

Bath bombs fizz due to the mixture of two ingredients instead of one agent: baking soda and citric acid. These ingredients may not do a lot on their own, but when you combine and add water to the mix, they’ll react against each other while cornstarch controls such reaction.

Baking soda and citric acid will react (producing carbon dioxide bubbles) immediately after the bath bombs are thrown into the bathtub full of water. This process is known as an acid-base reaction, where the baking soda or sodium bicarbonate acts as the weak base, while the citric acid is the weak acid, of course. Once the reaction happens, the bath bomb will start dissolving and releasing all of its ingredients, such as oils and fragrances.

Hence, although water triggers the reaction almost immediately, cornstarch acts as a “controller” agent between both forces, making the bath bomb fizz at a more controllable pace. This mechanism also prevents a frothy fizz from happening.

How long should a bath bomb fizz?

This factor depends on the manufacturer and the bath bomb’s size. Of course, bigger bath bombs will fizz for longer than smaller ones, but averagely, layered bath bombs can take up to five minutes to stop fizzing and dissolve at their fullest.

Please note that this period isn’t applicable in all cases. It is unlikely for two bath bombs to have the same dissolving time, especially if we take into account the individual structure of each one. For instance, let’s suppose that the bath bomb has a very specific mix in the middle that’s bursting to break out. Once it finds a hole, it will start propelling to the outside. However, if there are multiple holes available, then the substance will probably get out even faster. Hence, it’s a bit complicated to tell you for how long a bath bomb should fizz.

What’s recommended is to throw your bath bomb in the bathtub, then wait for about five or six minutes. Then, observe if the bath bomb is still fizzing until you’re ready to enter the tub.

Will a bath bomb fizz in cold water?

If you’ve heard that bath bombs don’t fizz in cold water, that’s not true – at least not entirely. However, the colder the water, the harder it is for the bath bomb to fizz.

It’s not very recommendable for you to throw a bath bomb in the tub if you’re trying to have a cool bath as the whole process is slowed down. Although the chemical reaction described above still happens as baking soda and citric acid have come in contact with water, it may appear like it’s happening slowly due to the water’s low temperature. 

If you enjoy making your own bath bombs, it’s possible to modify your recipe a bit, so the ingredients responsible for the fizzing react faster when they come in contact with the cold water.

How to speed up a bath bomb’s fizz in cold water

As mentioned above, it’s possible to modify your DIY bath bomb recipe so they work as they should in cold water. It only needs a few modifications to make it act quicker in lower temperatures.

  • First, you can try adding more citric acid. This way, you’ll increase the citric acid to baking soda ratio, but it can be hard to achieve the perfect quantity during your first try. So, play around with the quantities for a while until you find the optimal citric acid amount to make your bath bomb work quicker in cold water.
  • If possible, don’t use too much cornstarch or remove it from the recipe. Remember, this ingredient is meant to “slow down” the reaction. Hence, since you’re already using cold water, it will not be necessary. You can choose to erase it from the ingredients list or add a small amount just to be loyal to your recipe.

Why do bath bombs dissolve quicker in hot water?

All bath bombs are designed to dissolve faster when they come in contact with hot water. This happens because those higher temperatures cause the chemical reaction between baking soda and citric acid to happen more rapidly. 

A warm bath will make sure that your bath bomb dissolves completely while fizzing as it should. Also, maybe it will cause it to produce more bubbles, which can be an excellent idea for your bath time.

In addition, bath bombs work exceptionally well in hot water. This is because their secondary ingredients (all the oils, fragrances, and detergents utilized in the mix) are easier to dissolve in higher temperatures.

How do you make super fizzy bath bombs?

If you’d like to have even “fizzier” bath bombs, here we have the perfect recipe you can follow. But, of course, you’re free to modify it based on your preferences. Also, although we include cornstarch in the recipe despite saying it reduces the “fizzing” effect, feel free to remove it or add a minimum quantity of it as you continue with each step.

What you’ll need

This recipe is pretty easy to follow – here are all the equipment and ingredients you’ll need to go through it from beginning to end. 


  • A mixing bowl
  • A few measuring spoons or any other utensil that serves the same purpose
  • Another spoon for stirring the ingredients
  • Molds for bath bombs! You can do them yourself or purchase them from any local store.


  • Half a cup baking soda
  • Half a cup citric acid – You can add a bit more if you’d like the bath bomb to fizz more than it would in the traditional recipe.
  • Half a cup cornstarch – You’re free to skip this ingredient or reduce the quantity if you’d like the bath bomb to fizz longer or for more time. It is also recommended to do either of the options mentioned if you’re thinking of using the bath bomb in cold water.
  • Food coloring of your preference
  • Any essential oil you like
  • And water. 

The process

Once you’ve collected all the ingredients, you can proceed to start with the recipe. 

Step one: Mix the dry ingredients

Grab your mixing bowl, and put the cornstarch and baking soda. Use a spoon to stir them and mix them all together. If you find clumps, use the spoon to break them; otherwise, they may ruin the result. You can skip to the next step if you’re not using cornstarch for your bath bombs.

Note: If you want to make different bath bombs because you’d like to have diverse colors, it’s recommendable to separate the dry ingredients in different mix bowls at even parts. You’ll also need to divide the citric acid into equal parts so everything remains balanced.

Step two: Add essential oil

Please choose your preferred essential oil, and add a few drops slowly until it is perfectly integrated into the mixture. It can be difficult to do it with a spoon, but using your hands will speed up and make this step much easier. It’s recommended to wear gloves to avoid the essential oil’s fragrance from sticking to your hands.

Step three: Add the coloring

Next up, it’s time to mix the food coloring into the dry mixture. Using fewer drops will grant you softer tones, while adding more drops will saturate the color gradually.

Step four: Add water

Now, it’s time to add water slowly. Don’t add more than ½ a teaspoon at a time; otherwise, you’ll ruin the mixture. After each teaspoon, stir up the mix to make it even. Continue adding water until you notice that the texture is similar to how damp sand would feel.

Step five: Add citric acid

Add the citric acid and combine it with the rest of the mix until it’s perfectly combined. It’s recommended to use your hands to make the process faster and less tedious.

Step six: Mold the ball

Take your bath bomb molds and fill each side with the mix – try to overfill them a bit. Then, proceed to press both parts together, constricting them as much as possible for a few seconds. Now, you can take off the mold from one side, then place the soft side into your hand and pull the other mold. Please try to be as gentle as possible during this step, as the mixture hasn’t dried up, and it can come undone if you’re too rough.

Step seven: Smooth the ball

This step is optional as your bath bomb is practically ready. You can use the spoon’s back to smooth the bath bomb’s finish, especially in the middle part – where the molds got together.

Final step: Let them dry!

All you have to do now is wait until your bath bombs have hardened – leave them at room temperature overnight. Then, you can store them in a secure container or wrap them in a plastic bag to prevent them from being damaged.

Why is my bath bomb fizzing slowly? And is this a good sign?

There are various reasons why your bath bombs are fizzing slowly. Please note that this is an indicator that something is wrong, so it isn’t necessarily a good sign.

  • Maybe you’re trying to use your bath bomb in cold water. Please note that all the ingredients included in a bath bomb react more rapidly in warm water. Coldwater will slow down the chemical reaction.
  • If you’ve made DIY bath bombs, try not to use too much oil. It can be the responsible agent of your slow-fizzing bath bomb.
  • Make sure that you’re keeping your bath bombs in enclosed containers or wrapped up in plastic. Bath bombs are pretty vulnerable to the air’s moisture and humidity. Hence, if you’re keeping your bath bombs in a dap environment, we recommend you wrap them in plastic and keep them in an airlock container to avoid them from getting moisture.

How to make bath bombs fizz longer?

There are plenty of ways to make your bath bombs fizz for a longer period. Please note that some of the following methods can make the bath experience quite underwhelming, though.

  • Make the bath bomb denser. While making the bath bomb, try to compact the molds together as much as possible. This will make it more challenging for the water to penetrate into the mix and cause a chemical reaction. Hence, it will start fizzing away at a slower pace once it comes in contact with water.
  • Add more cornstarch. If you’d like your bath bombs to fizz longer, adding more cornstarch will help slow down the chemical reaction.
  • Avoid salts. Although there isn’t an enormous difference, not using salts – especially Epsom salts – will make the bath bomb fizz at a slower pace. However, using less sodium in your bath bomb will compromise its quality a lot.
  • Don’t use oils. Oils are known to slow down the reaction, so it’s recommended to use them in minimum quantities or not to use them at all. However, not using enough oil may leave your bath bomb scentless. Adding coconut oil or any carrier oil as a replacement may help you with the issue. It shouldn’t be a problem for you if you’re okay with using bath bombs without fragrance.
  • Change the recipe ratio. The traditional baking soda-citric acid ratio is 2:1. However, switching up this factor will make a noticeable change, which will “reduce” the reaction between both agents. It’s recommended to try a few experiments to figure out the optimal ratio for your preferences.
  • Add SLSA. It may not make such a big difference while slowing down your bath bomb, but it will add some nice bubbles when the item starts dissolving.

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