Happy almost-Valentine’s-Day! We’re celebrating this year with some seasonal bath bombs, featuring some shimmery mica painting and lovely pink fizzing. They smell beautifully of rose and lemon, in keeping with the shampoo bars I shared last week, but you could definitely choose a different valentine-y scent if you wanted to! Florals, vanilla, and/or chocolate all come to mind as deliciously seasonal scents 😄 I pressed these bath bombs into cubes using The Bath Bomb Press, though you can also hand-mould them if you don’t have a press.

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The base of these bath bombs is one I developed after getting The Bath Bomb Press and realizing the small sphere mould + my earlier base formulas weren’t compatible. You can read more about that development process here. As with all bath bombs, it’s a combination of basic (baking soda) and acidic (citric acid + Cream of Tartar) ingredients. We keep everything as dry as possible, adding just enough moisture to bind everything together without triggering a reaction. Once they’re done you can plop a bath bomb or two in the tub and the reaction will kick off in the tub, filling your bath with fizzy fun!

My favourite thing about this development is the inclusion of the witch hazel right in the formula rather than the mist-mist-mix-mix frenzy I’ve been doing for years. It’s so much better this way! Simply measure, mix, and press—no fussing with trying to get things just right.

The cute little hearts on these bath bombs were made with a simple mica paint—a blend of 99% isopropyl alcohol and mica. The alcohol evaporates really quickly without reacting with the bath bombs so we can paint with the liquified mica. Ever since watching this video from Ariane I’ve been meaning to try mica painting on bath bombs and I finally got around to it! It was easy and fun and quite meditative. It also made me realize that I no longer own any crafting paintbrushes—I had to use one of my least favourite makeup brushes 😂

Once I was done with the painting I misted the bath bombs with some more 99% isopropyl alcohol and dusted them with some silver and red biodegradable glitter for a bit of extra sparkle. If you don’t want to take the time to paint the bath bombs you could easily do a mica splatter instead (make up the same mica/alcohol slurry and splatter/drizzle the bath bombs with it using a disposable pipette), or just the glitter sprinkle. Or nothing! It’s up to you.

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Argan Rose Valentine Bath Bombs

4.16g | 0.52% witch hazel
0.24g | 0.03% red #40 water soluble dye

424g | 53% baking soda (USA / Canada)
76.8g | 9.6% Epsom salt (USA / Canada)

12.8g | 1.6% Polysorbate 80 (USA / Canada)
20g | 2.5% argan oil
3.2g | 0.4% rose fragrance oil
2.8g | 0.35% lemon slices fragrance oil

216g | 27% citric acid (USA / Canada)
40g | 5% Cream of Tartar

To decorate:

• Red mica
• White colour-shifting biodegradable glitter
• Red biodegradable glitter
• 99% isopropyl alcohol or isododecane, as needed

Weigh the witch hazel and dye into a small dish and whisk to combine/bloom.

Weigh the baking soda and Epsom salts into a large bowl. Stir to combine, and then add the dye/witch hazel mixture. Put on a pair of disposable nitrile or latex gloves and blend the mixture thoroughly.

Weigh out the Polysorbate 80, argan kernel oil, and fragrances. Weigh those into the bowl and blend thoroughly with your gloved hands.

Last up, weigh in the citric acid and cream of tartar, and blend that into the mixture as well. When you’re done you should have a clumpy mixture that holds together well when squeezed firmly.

Now it’s time to mould the bath bombs! You can hand-mould these, as described in this post/demonstrated in the partner video, but I opted to press these bath bombs with my beautiful new Bath Bomb Press and the 1.75″ cube mould. I set the press to ~45psi and pressed 80g of the mixture for each bath bomb. Be sure to watch the video to see this in action! The mould can hold 100g (3.5oz) of bath bomb mix and I’ve done that, too—it requires a bit more fussing and pre-packing to get it all to fit enough to press it, but the end result is much more cube-like. 

Once the bath bombs have been moulded I left them to dry overnight before decorating them.

For decorating, start by mixing up your “paint” by stirring a spoonful of mica together with some 99% isopropyl alcohol to create a slurry. Grab a paintbrush and use that to paint a heart on the top of each bath bomb.

Substitutions

As always, be aware that making substitutions will change the final product. While these swaps won’t break the recipe, you will get a different final product than I did.

• As I’ve provided this recipe in percentages as well as grams you can easily calculate it to any size using a simple spreadsheet as I’ve explained in this post. As written in grams this recipe will make 800g. The number of bath bombs this makes is entirely dependent on the size of your mould. I made ten 80g bath bombs, give or take whatever is lost during pressing.
• To learn more about the ingredients used in this recipe, including why they’re included and what you can substitute them with, please visit the Humblebee & Me Encyclopedia. It doesn’t have everything in it yet, but there’s lots of good information there! If I have not given a specific substitution suggestion in this list please look up the ingredient in the encyclopedia before asking.
• Don’t substitute the baking soda or citric acid.
• You don’t have to use the dye if you don’t want to; replace it with more witch hazel if you don’t want colourful bath bombs. Made as written these bath bombs will tint your bath water a pale pink.
• If you do want colourful bath bombs, but you don’t have a water-soluble dye, replace the dye with more witch hazel and then swap out 0.5% Epsom salts for a mica of choice.
• You could try a different salt in place of Epsom salts.
• You can try replacing the Cream of Tartar with more citric acid, but the Cream of Tartar makes the bath bombs much harder and easier to mould.
• Give this a read for Polysorbate 80 alternatives.
• You can substitute the argan oil for another lightweight, inexpensive liquid oil like sweet almond, grapeseed, or sunflower seed.
• The fragrance is up to you. You could use a bath-safe essential oil instead, or any fragrance oil you like.
• The glitter topping & mica paint is optional, but pretty!
  • Don’t use 70% isopropyl alcohol instead of 99%; 70% will react with the bath bombs, causing them to swell under the painting like this.