If you love a long, relaxing bubble bath, these DIY strawberry bubble bars are such a fun way to make bath time feel a little more special.
A bubble bar is essentially bubble bath in a solid form. Instead of pouring liquid bubble bath under running water, you crumble part of the bar underneath the faucet and let the running water work it into the bath. The result is a tub full of fluffy bubbles with a sweet strawberry scent.
These strawberry bubble bars are made with a combination of powdered ingredients, surfactant, butters, and lightweight oil. The butters help bind the mixture together and give the finished bars a firm texture, while SLSa provides the bubbles you want from a bubble bar.
And because you’re making them yourself, you can change the fragrance, colors, and molds to create completely different bubble bars using the same basic idea.
What Is a Bubble Bar?
A bubble bar is a solid bath product designed to create bubbles when it is crumbled under running bath water.
Unlike a traditional bath bomb, where the main goal is fizzing, a bubble bar is formulated around creating lots of bubbles. SLSa is the primary foaming ingredient in this recipe, while baking soda and citric acid help create the solid structure and add some fizz when the bar hits the water.
One of the things I really like about solid bubble bars is that you don’t have to use an entire bar at once.
If you make larger bars, simply break off the amount you want for each bath. You can also make smaller bars if you want individual portions.
Watch the Full Video Tutorial
If you’d rather see the process before making these, the video walks through the mixing, coloring, molding, and unmolding process.
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Strawberry Bubble Bar Recipe
This recipe makes approximately 6 ounces of strawberry bubble bar mixture.
The formula is written in percentages as well as ounces so you can see exactly how the recipe is balanced. If you eventually want to make a larger batch, you can use the percentages to calculate the new amounts.
| Ingredient | Percentage | Weight |
|---|---|---|
| Baking Soda | 40% | 2.40 oz |
| Citric Acid | 12% | 0.72 oz |
| SLSa | 20% | 1.20 oz |
| Cream of Tartar | 4% | 0.24 oz |
| Kokum Butter | 8% | 0.48 oz |
| Shea Butter | 8% | 0.48 oz |
| Fractionated Coconut Oil | 2% | 0.12 oz |
| Vegetable Glycerin | 2% | 0.12 oz |
| Polysorbate 80 | 2% | 0.12 oz |
| Strawberry Fragrance Oil | 2% | 0.12 oz |
| Total | 100% | 6 oz |
You’ll also need
- Red mica or another bath-safe colorant
- Green mica or another bath-safe colorant
- Strawberry-shaped silicone mold
- Heat-safe container for melting the butters
- Mixing bowl
- Whisk or spatula
- Kitchen scale
- Wax paper or another clean work surface
- Double boiler
What Each Ingredient Does
Understanding what each ingredient contributes makes it much easier to make changes to a formula later. It also helps explain why this recipe contains more than just baking soda, citric acid, and a foaming ingredient.
Baking Soda
Baking soda makes up the largest portion of this recipe.
It helps form the dry base of the bubble bar and works together with citric acid to create fizz when the finished bar comes into contact with water.
The fizz isn’t the main attraction here — the bubbles are — but that reaction helps the solid bar break apart in the bath.
Citric Acid
Citric acid works with the baking soda to create the familiar fizzing reaction you see when the bubble bar hits water.
Because this is a bubble bar rather than a traditional bath bomb, citric acid is used at a lower percentage than you might find in some bath bomb formulas.
SLSa
Sodium Lauryl Sulfoacetate, usually shortened to SLSa, is the ingredient responsible for the bubbles in this recipe.
It is a powdered surfactant, which means it helps lower the surface tension of the water and allows bubbles to form.
SLSa is extremely lightweight and can become airborne easily. Take your time when measuring and mixing it rather than pouring or whisking it aggressively.
When working with powdered SLSa, take care not to create unnecessary dust. A face mask can be helpful when measuring and mixing it.
Cream of Tartar
Cream of tartar helps give the finished bubble bar a firmer texture and also contributes to the bubbling action.
It is a relatively small part of the formula, but it helps with the overall structure of the finished bar.
Shea Butter
Shea butter adds a rich, conditioning element to the formula while also helping bind the dry ingredients together.
It is soft compared with kokum butter, which makes it useful for helping create a workable dough-like mixture.
If you don’t have shea butter, mango butter can be used as a possible substitution.
Kokum Butter
Kokum butter is a firm, brittle butter that helps the bubble bars hold their shape once they have dried.
This is especially useful when you’re making shaped bubble bars because you want the finished strawberry shapes to release from the mold without immediately falling apart.
Cocoa butter can be used as a possible substitution.
Fractionated Coconut Oil
Fractionated coconut oil is a lightweight liquid oil that helps moisten the dry ingredients and contributes some conditioning properties to the finished bath product.
Because it stays liquid at room temperature, it is easy to incorporate into the melted butter phase.
A lightweight carrier oil such as sweet almond oil can be considered as a substitution.
Vegetable Glycerin
Vegetable glycerin helps make the mixture more workable and easier to press into the silicone mold.
It also acts as a humectant, meaning it attracts moisture.
Because bubble bars need to stay dry while they are being stored, don’t add extra glycerin simply because the mixture seems dry. Too much liquid can make the bars more difficult to dry and store.
Polysorbate 80
Polysorbate 80 helps disperse the oils and fragrance throughout the bath water.
Without an ingredient like this, oils and fragrance can be more likely to float on the surface of the water instead of dispersing evenly.
Strawberry Fragrance Oil
The fragrance oil gives these bubble bars their strawberry scent.
When choosing a fragrance oil for bath products, always check the supplier’s usage recommendations and make sure the fragrance is approved for the type of product you’re making.
You can replace the strawberry fragrance with another bath-safe fragrance if you want to create a different scent.
Colorants
The red and green colors turn the plain bubble bar mixture into strawberry-shaped bars.
Use colorants intended for bath and body products rather than food coloring or craft colorants. The amount needed will depend on the colorant you’re using and how intense you want the finished color to be.
How to Make Strawberry Bubble Bars
1. Prepare your workspace
Start by cleaning your work area and gathering everything you’ll need.
Because this recipe contains several powdered ingredients, I like to have everything weighed before I begin mixing. It makes the process much easier and keeps you from having to stop halfway through the recipe.
Measure each ingredient by weight using a digital scale.
2. Melt the butters
Place the shea butter, kokum butter, and fractionated coconut oil into a heat-safe container.
Set the container over a double boiler and gently heat until the butters have completely melted.
Be sure to mix while heating. The goal is simply to melt the solid butters so they can be incorporated into the rest of the formula.
Once melted, remove the container from the heat.
3. Combine the dry ingredients
In a separate mixing bowl, add:
- Baking soda
- Citric acid
- SLSa
- Cream of tartar
Mix the powders together gently.
Take your time with this step, especially when working with SLSa. Avoid pouring the powder from high above the bowl or mixing aggressively enough to create a cloud of dust.
4. Combine the wet and dry ingredients
Slowly add the melted mixture to the bowl containing your dry ingredients.
Begin mixing with a spatula or spoon, then continue working the mixture until it starts coming together.
This part takes a little patience.
At first, the mixture may look too soft or wet to become a solid bubble bar. Keep mixing until the ingredients are evenly incorporated and the mixture develops a dough-like consistency.
The finished mixture should be workable enough to press firmly into a silicone mold.
5. Divide and color the mixture
Set aside a small amount of the mixture for the green strawberry tops.
Add green mica to that portion and mix thoroughly.
Add red mica to the larger portion and mix until the color is evenly distributed.
You don’t need a huge amount of color. Start with a small amount and add more if necessary until you reach the shade you want.
6. Fill the strawberry mold
Place the red bubble bar mixture to the strawberry portion.
Take a small amount of the green mixture and press it into the leafy portion of the strawberry mold.
Press the mixture firmly into the mold.
This is important because a loosely packed bubble bar is much more likely to break when you remove it from the mold.
Smooth the bottom of each strawberry once the mold is filled.
7. Remove the bubble bars from the mold
Silicone molds make releasing the finished bars fairly simple, but don’t rush this part.
Instead of pushing directly against the center of the strawberry, gently pull the sides of the silicone mold away from the bubble bar.
Then turn the mold over and carefully release the strawberry. You might need to wiggle them out and pull on sides of the mold.
This helps prevent the indentation that can happen when you push directly on the center of the finished bar.
8. Let the bubble bars dry
Place the finished strawberry bubble bars on wax paper and allow them to dry completely.
This will generally take about 24–48 hours, although the actual drying time can vary depending on the humidity in your home.
Don’t package the bars until they are completely dry.
If they still feel soft, give them more time.
Tips for Making Better Bubble Bars
Don’t rush the mixing process
The mixture needs time to come together.
If it looks a little strange when you first combine the ingredients, keep working it before deciding that something has gone wrong.
You’re looking for a dough-like consistency that can be packed into the mold.
Pack the mold firmly
One of the easiest ways to end up with fragile bubble bars is not packing the mixture firmly enough.
Press the mixture into all of the details of the strawberry mold, especially around the edges and the leafy top.
Keep moisture away from the mixture
Bubble bars contain ingredients that react with water, so humidity can work against you.
Try to make them on a dry day if possible, and keep water away from your workspace while you’re making them.
Give them enough drying time
The outside may feel firm before the inside has completely hardened.
Give the bars the full drying period before wrapping or storing them.
If your home is humid, they may need longer than 48 hours.
Be careful with SLSa
SLSa is a very fine powder and can easily become airborne.
Avoid dumping it quickly into the bowl or mixing it aggressively. If you are sensitive to airborne powders, wear a face mask while measuring and mixing.
How to Use a Strawberry Bubble Bar
You don’t necessarily need to use an entire bubble bar in one bath.
For a larger strawberry bubble bar, break off the amount you want to use.
Turn on the bath water and crumble the bubble bar directly underneath the running faucet.
The running water helps work the bubble bar into the bath and encourages the formation of bubbles.
Once the bar has been added, use your hand to agitate the water if you want even more bubbles.
The amount of bubble bar you’ll need will depend on the size of your tub and how much foam you prefer.
How to Store Bubble Bars
Bubble bars need to stay dry between uses.
Once your bars have completely dried, store them in an airtight container or sealed bag.
A zip-top bag or airtight plastic container works well.
Keep the container away from humidity and water, particularly if you’re storing the bars in a bathroom.
If you are giving them as gifts, make sure they are completely dry before packaging them.
Can You Change the Ingredients?
There are a few easy ways to customize this recipe without changing the basic idea of the bubble bar.
Change the fragrance
Strawberry is perfect for these little strawberry shapes, but you can use another fragrance oil if you want a different scent.
Always check the fragrance supplier’s usage rate and product recommendations before using it in a bath product.
Change the color
The strawberry shape doesn’t have to be red.
You can use different colors to create other fruit-inspired bubble bars or simply choose a color that matches your fragrance.
Just make sure your colorant is intended for bath and body products.
Change the mold
The strawberry mold is what gives this recipe its personality, but the mixture can be pressed into other silicone molds as well.
This is one of the easiest ways to turn the same basic recipe into something appropriate for different seasons, holidays, or gifts.
Butter substitutions
If needed, shea butter can be replaced with mango butter, while kokum butter can be replaced with cocoa butter.
Keep in mind that changing ingredients can change the texture and firmness of the finished bubble bar, so it’s best to make a small test batch when experimenting.
Frequently Asked Questions
How long do strawberry bubble bars take to dry?
They generally need about 24–48 hours to dry, but humidity can make a significant difference. If the bars still feel soft, allow them to dry longer before packaging.
Can I use a different fragrance?
Yes. You can use another fragrance oil as long as it is appropriate for bath and body products and you follow the supplier’s recommended usage rate.
Can I use an essential oil instead?
This recipe was developed with fragrance oil, so I would not simply swap in an essential oil at the same percentage. Essential oils have different usage considerations and should be evaluated individually for the intended bath product.
Why is my bubble bar too soft?
The mixture may need more time to firm up, especially before it has dried completely.
Humidity can also affect drying.
If you are making the recipe exactly as written, allow the finished bars adequate drying time before deciding that the formula is too soft.
Why did my bubble bar crumble when I removed it from the mold?
The mixture may not have been packed firmly enough into the mold, or the bar may not have dried long enough.
When filling the mold, press the mixture firmly into all of the details. When unmolding, gently pull the silicone away from the sides rather than forcing the bar out.
Do these bubble bars fizz like bath bombs?
They will have some fizz because the formula contains baking soda and citric acid, but the main purpose of the recipe is to create bubbles.
If you’re looking for a product where fizzing is the main feature, a bath bomb is a better choice.
Do I need to use a preservative?
This recipe does not contain added water, and it is designed to be stored as a dry product. A preservative isn’t simply something you add to every bath product automatically; preservation depends on the product’s water content, formulation, packaging, and potential for contamination.
Keeping these bars completely dry during storage is important.
Final Thoughts
These strawberry bubble bars are one of those DIY projects that are just plain fun to make.
The strawberry shape makes them especially cute for gifts, but the recipe itself is also a good introduction to working with solid bath products. You get to practice combining powdered ingredients, working with melted butters, creating a moldable mixture, and understanding what each ingredient contributes to the finished product.
Once you’ve made a batch, you can start experimenting with different fragrances, colors, and molds to create your own versions.
And of course, the best part is getting to crumble one into a warm bath and enjoy all those bubbles.
Printable Strawberry Bubble Bar Recipe
DIY Strawberry Bubble Bars
Equipment
- Scale
- Strawberry Silicone Mold
Ingredients
- 2.40 ounce | 40% Baking Soda
- 0.72 ounce | 12% Citric Acid
- 1.20 ounce | 20% SLSa
- 0.24 ounce | 4% Cream of Tartar
- 0.48 ounce | 8% Kokum Butter
- 0.48 ounce | 8% Shea Butter
- 0.12 ounce | 2% Fractionated Coconut Oil
- 0.12 ounce | 2% Vegetable Glycerin
- 0.12 ounce | 2% Polysorbate 80
- 0.12 ounce 2% Strawberry Fragrance Oil
Instructions
Prepare ingredients
- I like to start out by cleaning my work area and weighing out all the ingredients.
Melt Butters
- Place the shea butter, kokum butter and fractionated coconut oil in a heat safe container. Place in a double boiler until the butters are completely melted.
Dry Ingredients
- Add all of the dry ingredients (baking soda, citric acid, SLSa, and cream of tartar) to a bowl and mix lightly with a whisk.
Wet Ingredients
- Add the melted butters and the remaining wet ingredients (vegetable glycerin, polysorbate 80, fractionated coconut oil and strawberry fragrance oil) to your oils.
Combine
- Combine the wet and dry ingredients together. It is going to take quite a bit of mixing to get it to your dough-like consistency. The finished mixture is going to feel a little too wet for a bubble bar, just trust that it will harden up for you.
Coloring
- Take out a small portion of the strawberry bubble bar mixture for the green tops of the strawberries. Add a green mica powder and mix well. Add a red mica powder to the remaining bubble bar mixture and mix well.
Making the bubble bars
- Layout a piece of wax paper over your work area. Place the dough in the center and grab your Strawberry Silicone Mold. Add a bit of the red bubble bar mixture to the center of the strawberries and the green on the tops. Be sure that you pack them in the mold well and smooth out the bottoms. To remove from the mold, you can push in the center of the mold. However, that leaves a little dent in the center of the strawberries. The other way to get them out (without the dent) is to pull on the sides of the mold to help release it. Then tip it upside down (while pulling the sides apart). The strawberry bubble bars will pop out.
Allow to Dry
- You are going to want to leave the DIY strawberry bubble bars on the wax paper for about 24 – 48 hours to dry fully. Now it could be longer depending on the humidity where you live.