One of the things I absolutely have to make every year as part of my holiday DIYing is bath bombs—my mom loves them, so I need to make sure she’s set for the following year 😊 This year’s holiday bath bombs are Ice Palace themed, with a fizzy surprise in the centre and an abstract shimmery topping. They pair beautifully with the Ice Palace Soap from last month and the body wash from last week, too ❤️ Let’s dive in!

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As usual, the bulk of these bath bombs is a blend of basic sodium bicarbonate (baking soda) and acidic citric acid that fizz up beautifully when dropped into a tub of water. I’ve also included some sparkly Epsom salts and acidic Cream of Tartar, which makes moulding the bath bombs a heck of a lot easier. If the only Cream of Tartar you have is a tiny tin in the kitchen, you’ll definitely want to look into ordering your Cream of Tartar online. DIY supply shops sell large quantities for prices that blow the grocery store out of the water!

I did something new-to-me with these bath bombs—I created a concentrated blend of baking soda, citric acid, and blue water-soluble dye, and secreted a quarter teaspoon or so of that mixture in the centre of each bath bomb. This means the white bulk of the bath bombs happily fizz away for a while and then… hey… is that a bit of blue? It is! Look at all that blue! It’s very fun, and worth the wee extra step when forming the bath bombs. I did consider putting a hefty amount of biodegradable glitter in the blue dye mixture as well, but ended up deciding the mess factor of all that glitter outweighed the “oooh, pretty” factor.

If you’re used to the spritzing witch hazel/frantic mixing method of making bath bombs, I think you’ll appreciate the method I’m using here. We thoroughly blend the wet ingredients into the baking soda and Epsom salts, and then blend the acidic ingredients into that nicely diffuse mixture. No fussing with quickly incorporating tiny amounts of liquid without setting everything off! I learned this from binge-watching Ariane’s bath bomb videos, and it is a massive upgrade to your bath bomb making!

I used the Bath Bomb Press to mould these bath bombs, but you definitely don’t have to—they also work well in a hand-held spherical mould, or you can pack ’em into a measuring cup. You could also try a moon cake press if you have one!

For decoration, I drizzled these bath bombs with an ice palace inspired mica/isopropyl alcohol slurry. The version I made for the blog uses a colour-shifting mica that looks silver-white but shifts softly to a cool purple. That worked fairly well, but I do like the tri-colour version I made in the video better. It’s 100% up to you, though! I hope you and your giftees enjoy these shimmery bricks of bathtime indulgence 😄

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Ice Palace Bath Bombs

4.32g | 0.54% witch hazel distillate (USA / Canada)
14.08g | 1.76% Polysorbate 80 (USA / Canada)
20.8g | 2.6% fractionated coconut oil
4g | 0.5% Salty Sea Air fragrance oil

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

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

Coloured core (20g batch)
0.1g | 0.5% blue water-soluble dye
10g | 50% baking soda (USA / Canada)
9.9g | 49.5% citric acid (USA / Canada)

To decorate

• 99% isopropyl alcohol (USA / Canada) or isododecane (USA / Canada) (as needed)
• Tri-colour option (shown in video):
  • Purple (Lilac Whisper) mica
  • Pink (Blushed Pink) mica
  • Blue (Neptune) mica
  • Silver-white (Arctic white) mica
• Colour-shifting/irridescent option (shown here):
  • White mica with a lilac, pink, or blue color-shift

Weigh the witch hazel, Polysorbate 80, fractionated coconut oil, and fragrance oil into a small dish or beaker.

To make the coloured core powder: weigh out the three ingredients and massage them together with gloved hands. Set aside.

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

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 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.

To press/mould the bath bombs: put about 70% of the white base into the mould, and then create a hollow core by poking a gloved finger into the mixture to approximately the half way point. Spoon a small amount of the coloured core powder into that hole (~1/4 tsp). Top with the rest of the white base, and then press/mould.

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

For decorating, start by mixing up your “paints” by stirring mica together with some 99% isopropyl alcohol. I blended small amounts of the coloured micas into the silver-white mica for a subtle colour effect, making three different paints (purple, pink, and blue). I then used a small disposable pipette to splatter each paint over the bath bombs and left that to dry. Watch the video to see this in action!

To use, drop a bath bomb into a hot bath and enjoy!

Shelf Life & Storage

Because this product does not contain any water, it does not require a broad-spectrum preservative (broad spectrum preservatives ward off microbial growth, and microbes require water to live—no water, no microbes!). Kept reasonably cool and dry, it should last at least a year before any of the oils go rancid. If you notice it starts to smell like old nuts or crayons, that’s a sign that the oils have begun to oxidize; chuck it out and make a fresh batch if that happens.

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 + 20g for the coloured core mixture. This will make ten 80g bath bombs, with a decent chance you’ll have some coloured core mixture leftover.
• To learn more about the ingredients used in this formulation, 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 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 another lightweight oil like sweet almond, grapeseed, or sunflower seed oil instead of fractionated coconut oil.
• The fragrance is up to you. You could use a bath-safe essential oil instead, or any fragrance oil you like.
• The shimmery topping 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.
• For the colourant in the core: you need to use a water-soluble dye, though you could use a different colour. A mica will not work as they are not potent enough, and oxides/ultramarines won’t work as they are insoluble.