Why Do Bath Bombs Crack?

Making bath bombs get regarded as a great project ideal for both the advanced crafters and beginners. Though making them is easy, one needs to practice. When exposed to moisture, bath bombs can get finicky, and when made with the wrong ingredients, they fizz incorrectly, fall apart, and crumble. You may be making bath bombs for fun, as a hobby, or professionally but worry about the reasons why they crack. Relax and continue reading as today is your lucky day. In this article, we shall answer why bath bombs crack, and other questions bath bomb makers like you struggle with all the time.

Citric acid and baking soda get used in making bath bombs. When these two ingredients get mixed and put in the water, the result is a fizzing reaction. The ideal ratio used is usually one part of citric acid to two parts of baking soda. After combining these two dry ingredients, a liquid in small amount gets added to create a moist, moldable sand texture. Mostly, the Witch Hazel get used as the liquid, but you can also add kinds of butter and oils for moisture and to enhance your skin. Also, you can customize your bath bomb mixture by adding color, fragrance, and shape. In this regard, bath bomb makers come up with thousands of questions regarding them, the major one being why they get to crack. Let us continue by addressing most of these questions, starting with the primary one.

Why Do a Bath Bomb Crack?

You could be tired of always having your self-made bath bombs crack and you do not get to discover why. The reason could be that your mixture is usually too dry. You should try adding more oils or witch hazel to improve your mixture’s texture. The resulting mixture will not crack or crumble after removing it from the mold. When your fizzy cracks after removing it from the mold, it could have been too wet where the mixture starts expanding while still sitting in the mold, thereby causing the cracking. The right moisture of a bath bomb mixture should be firm but a moldable bath fizzy. Alternatively, your bath bomb may become soft. Let’s look at the reasons why.

Why Do a Bath Bomb Become Soft?

Too much moisture in the mixture causes the bath bomb to become soft. In case you put too much oil or witch hazel in your combination during the process of making the bath bomb, balance the mixture by adding more dry ingredients. Do you live in a wet climate or humid area? If so, the air contains moisture that prevents your bath bombs from hardening. But adding cornstarch or a clay such as Kaolin in small amounts could help them harden. Also, they cause the bath bombs to become sturdier. Sometimes the bath bombs may appear to have bumps, lumps, or warts and you have no idea why. Here is the cause;

bath bomb crack

Why Do Bath Bombs Have Bumps, Lumps and Warts on the Surface?

If your bath bomb has a bumpy texture, then your dry ingredients must have been having clumps, or maybe you didn’t mix the fragrance oil well. You should be careful with the baking powder as it’s notorious of clumping together. Ensure you break all the large clumps of your dry mixture with your hands before adding fragrance, oil, color or other additives. Smaller clumps get removed and broken up by pouring the mixture through a sifter with a fine mesh. It is an extra step, but it results in a smooth texture. Too much moisture in the fizzy also causes bath bomb warts. In this case, the essential oil or fragrance is the culprit. Add more dry ingredients to ensure the moisture gets incorporated fully. At times, your bath bomb may not fizz much, and you wonder why. Check out the reason herein below;

Why Do Bath Bombs Fizz Less?

Does it always bother you when your bath bomb doesn’t fizz in your tub as expected? You should stop being worried and increase the citric acid amount in your recipe. For a start, try mixing 1.5 parts of the citric acid with two parts of baking soda. Or could your recipe contain cornstarch? If that’s the case, eliminate it or reduce the amount. Also, if you use oil in your bath bomb mixture in large amounts, it will decrease the fizzing. The moisture found in the air due to a damp environment also causes the fizzing reaction of a bath bomb to fall. To avoid this, take a plastic wrap and wrap it tightly. Sometimes the bath bombs expand until they get out of the mold. It could be because of the following;

Why Do a Bath Bomb Expand Until It Gets Out of the Mold?

A Premature fizzing reaction and a very wet mixture get responsible for your bath bomb expanding until it gets out of the mold. A fragrance and colorant with water cause fizzing of the bath bomb mixture. It causes the fizzing in the tub to reduce. Moisture found in the air also causes premature fizzing. For instance, bath bombs made on a rainy or moist day expand while still in the mold. Talking of colorants, you may wonder the best ones to use. If that’s the case, they include the following;

bath bomb crack

What Colorants Get Used in Bath Bombs?

For those makers that prefer optimal coloring in their bath bombs, La Bomb colorants suit them best. These colorants get made from D&C and FD&C dyes in their high concentration like the LabColors. But they get made with Glycerin instead of water like in the LabColors. The advantage of the La Bomb colorants is that they don’t form warts and start fizzing when added to the mixture for making the bath bomb as the water-based dyes do. Also, Clays, Micas, and other natural colorants are ideal to use as colors for your bath bombs. All you need to do is to blend these colorants with the bath bomb mixture until thoroughly combined.

But you should note that powder colorants leave your skin and tub with color, and especially the large particle colorants such as the Pigments. If you do not like the color impression on your skin and tub, use the clays and micas. Use Polysorbate 80 as the emulsifier to prevent pooling on top your bath water when you mix oil and color. You can begin by adding 0.1 oz. of the emulsifier to one cup of the fizzy mixture. You are now aware of the color to use in your bath bomb, but you may not know the amount to use. The color used is as follows;

What Amount of Colorant Should Get Added into a Bath Bomb?

You shouldn’t worry about the amount of colorant to put into your bath bomb. But it gets recommended to start by adding small amounts of the colorant until you achieve your desired color. Due to the white color that comes with the citric acid and baking soda, getting darker tones like navy and red becomes like an uphill task. You get required to use more colorant to achieve the dark colors. As a result, your bath water becomes dark and leaves your skin and tub with too much color. But sometimes you may not have the right liquid like the witch hazel to add into your bath bomb mixture. You need not worry; here is what you can use;

What Can Get Used Instead of Witch Hazel?

Maybe witch hazel is unavailable, or you can’t afford it and are wondering what to use. Oils are ideal to use in your bath bomb mixture to create a moldable texture. In the effort of gaining the right feel for the bath bomb mixture, some crafters use water combined with 99% Isopropyl Alcohol. But you need to be careful with the amount of fragrance you put in your bath bomb. Are you aware of the quantity required? Then check out the following;

What Amount of Fragrance Should Get Added to a Bath Bomb?

The Bramble Berry Calculators are great in calculating the required amount of fragrance oil you should add in your recipe for making a bath bomb. You may worry about the usage of this calculator, but it’s easy to use. You only need to select the option labelled as “salt”. Then input the quantity of the dry ingredients you want to use in your bath bomb mixture. Select the essential oil or fragrance you intend to use. The calculator will, in turn, give you information on the quantity of fragrance you should use in your bath bomb’s recipe. While some recipes use volume measurement such as cups, the Fragrance calculator relies on weight measurements. In volume measured methods a nose can get used to determine the fragrance amount required. By just smelling, you get to decide whether you add more fragrance to make it stronger or not. You may also need to know about the quantity of other ingredients used in making a bath bomb like butter and oil. For the insight, check out the following;

What Quantity of Butter and Oil Should Get Added into a Bath Bomb?

The quantity of oil and butter shouldn’t bother you because you get free to add as much or less as you wish. Because kinds of butter and oils come with skin benefiting properties, you may need to put in your bath bomb mixture a reasonable amount. Too much oil or butter may cause your bath bomb to remain soft. Also, oils can cause slippery bathtubs and one need to get careful when getting out of the tub. But that depends on what you prefer as some people do not like oils in their bathing water. If you are the kind that loves butter and oil in your bath bomb, you should add them after mixing all the dry ingredients into a smooth mixture. If it’s your first time to use oil and butter in your bath bomb mixture, you may need to start with 1.5 cups of all the dry ingredient and 0.5 oz. of oil. Talking about oils, we may need to answer whether vanilla fragrance oil in a bath bomb causes discoloration.

Do Vanilla Fragrance Oil in a Bath Bomb Cause Discoloration?

If the vanilla content is high in the mixture, then the bath bomb will discolor your skin and tub. But the discoloration from bath bombs with vanilla fragrance oil gets inconsistency and appears after a long time. For instance, similar to the cold process soap, the stain from vanilla happens within hours or days. The vanilla discoloration may appear after weeks or months. Though sometimes you can add a vanilla stabilizer, it may not help in preventing the discoloration. To avoid all these hustles, use a non-discolor fragrance. What molds do you use in your bath bomb? Unfortunately, many people are not aware of the mold to use. If you are one of them, you may need to check out the following;

What Molds Are Ideal For a Bath Bomb?

The spherical shape mold comes in two parts and is among the most popular. For example, the Bath Bomb Mold & Package and Stainless Steel Bath Bomb. If you want to make unique shaped bath fizzies, ensure they are flexible but sturdy. You may need to consider plastic molds that come with individual cavities; they are great. Also, you can go for the silicone molds. For instance, for adorable cupcakes bath bombs, the Round Cupcake Silicone Mold works like magic. But you should leave your bath bombs in the mold for some time. Are you aware of up to when you should leave the mold to settle? Check it out;

bath bomb mold

Should a Bath Bomb Remain in the Mold for Long?

You can leave your bath bomb for several hours or overnight in the mold. If you remove it while soft, the bath bomb will crumble down! If it dries thoroughly while in the mold, handling and removing it becomes easier. But bath bombs may not stick together while in a mold made with stainless steel. Do you want to know why? Then continue reading.

Why Does a Bath Bomb Fail to Stick Together While in a Mold Made of Stainless Steel?

Getting the bath bombs’ two halves to stick together can get tricky sometimes. You find the mixture sticking to the side of the molds instead. But this shouldn’t bother you; just add Cyclomethicone drops to the molds’ sides. The amount should be between 5 – 10 drops. Ensure you swirl the mold around after adding drops of Cyclomethicone. Afterwards, drain the mold using a paper towel as it makes its removal extremely easy. You should also consider your fizzies’ texture; it’s very significant. Ensure the bath bomb mixture is wetter to hold its shape while in a stainless steel mold.

You are now aware of the solutions to many of your questions concerning bath bombs and may be you are ready to make one with no defect. But you get concerned on how to pack it well. Don’t worry, here is how you should pack your bath bombs.

How Do Bath Bombs Get Packed?

Packing bath bombs can get tricky because they are delicate. Bags, boxes, and jars are the popular methods used today. But if you use the Bath Bomb Mold & Package, it is a better option because it acts as both the mold and package. The best place to store your bath bombs is in a dry place with cool and room temperature, for example, in a cabinet, basement or garage. Maybe your climate is humid and are worried about what to do; no need to fret. Before placing the bath bombs in a bag or box, wrap them tightly using a plastic wrap. The fizzies will get protected from excess moisture by the plastic wrap.

Alternatively, in your fizzies’ package, put a silica packet to help absorb any additional moisture. But always remember that the silica packet shouldn’t get thrown in your tub. If sending to someone, let the person know that. A fan or dehumidifier helps in drying the fizzies. After packing your fizzies, you may wonder how long they last. Let’s check it out herein below;

How Long Should a Bath Bomb Last?

If you allow your bath bombs to stay for long, they get exposed to the moisture found in the air, making them lose some of their fizzing powers. The best time to stay with a bath bomb is about six months. Though the baking soda and the citric acid pride themselves of long shelf lives, the citric acid loses its potency when exposed to air. To avoid this, the container you’ve kept it in should be airtight. Because humidity is usually good in penetrating even through the tightest and smallest of places, it is better to use your fizzies for a short period like up to six months. Nothing is disappointing like putting the effort in making a bath bomb, and it comes out substandard, especially in its fizzing ability. As you make one, also consider the kinds of butter’ and oils’ shelf life; they will help you determine how long your bath bomb should last.

Proper Bath Bomb Molding Techniques


As illustrated above, making bath bombs is easy but tricky. Many makers of fizzies encounter numerous problems. We may not have solved all of them, but we have answered most of the questions the bath bomb makers struggle with all the time. With the answers given above, we are confident that you will get to make a perfect bath bomb. As you make your fizzies, remember adding the extras makes them stand out.

You may also read other articles like the best bath pillow and a reviews on a shower filter with vitamin c.

1 thought on “Why Do Bath Bombs Crack?”

  1. Can you remold a bath bomb after you have done them if they don’t dry. Mine appear to be too soft and they have been drying for two days. Can I go ahead and put them back in a bowl and try to remold them? Perhaps I need to add more citric acid or something to them to make them dry more?

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