Homemade bath bombs – the beginner's guide

Because bath bombs fizz, people sometimes think it might be hard to make them at home, but actually it's pretty easy. The fizz is all down to two very ordinary ingredients – baking soda, and citric acid.

Here's how it works. Citric acid is an acid, obviously, and baking soda is an alkali. As long as they're in powder form, you can mix them with no reaction. But when the bath bomb goes into the water, the two powders dissolve and are able to react with each other, and that chemical reaction is what creates the fizz.

So, for homemade bath bombs, all you need is some citric acid and some baking soda, and then you add in whatever you want in the way of fragrance, color, and oils.

Making homemade bath bombsWhat you need to make bath bombs:

Here's what you need for your homemade bath bombs. This is the basic recipe, and as you'll see, there's lots of room to vary the mixture – different kinds of salts, different fragrances and oils, etc. (If you want some inspiration, The Handcrafter's Companion has a ton of great ideas for recipes.)

You need the following dry ingredients, in these ratios:

  • 2 parts baking soda (note, baking soda is pure bicarbonate of soda – it's not the same thing as baking powder, which contains extra ingredients like starches)
  • 1 part citric acid

And you can include the following optional dry ingredients:

  • 1 part salt – this can be epsom salt, sea salt, or a mixture of the two
  • 1 part cornstarch (this makes the water and your skin feel soft and silky)

So, for example, we can use 2 cups of baking soda, and 1 cup each of citric acid, cornstarch, and salt.

You also need some wet ingredients. If we're using the above quantities of dry ingredients, you need:

  • About 2 tsp water (ideally filtered or distilled) or witch hazel (some people prefer witch hazel instead of water, as they feel it's less likely to set off the fizzing early). The amount that you need will depend on which of the optional ingredients you've chosen to add, and also the humidity where you live, so you just have to play this by ear – details on how to do that below.
  • 2 tsp of some kind of fragrance oil. This can be essential oil or perfume oil, but if the latter, make sure it's 'skin safe', rather than the stuff meant for oil burners

And you can include the following optional wet ingredients:

  • 2 tsp of any kind of skin-friendly vegetable oil, for soft and silky skin. Nut oils, seed oils, jojoba, olive oil etc – all good.
  • A few drops of coloring. Get 'soap safe' colorant if you can, as food coloring may stain your tub.

And here's the equipment you'll need:

  • A nice big bowl for mixing! Glass or metal is best – some plastics react badly to oils.
  • A whisk, and maybe some spoons, for mixing. A sieve can be helpful, too.
  • Measuring jugs, cups and spoons
  • Molds
  • A small squirty bottle for adding your water or witch hazel. An old lotion bottle works just fine if it's cleaned out thoroughly.

Making your bath bombs

  1. First mix the dry ingredients together in your mixing bowl. You want to make sure everything's really well mixed, and that there are no lumps, so stir, whisk, and sieve till you get to that point.
  2. Now add in your fragrance and color, plus the oil if you're using it – basically, all the wet ingredients except for the water or witch hazel. And mix it all together really well. Often it's easiest to do this by hand – just rub all the wet ingredients in, the way you would rub fat into sugar when you're baking. Keep rubbing till the color's evenly distributed through the mixture – it'll probably take about five minutes.
  3. This next stage is the bit where practice makes perfect, so take it slowly at first. You're going to spritz in just a little at a time of your water or witch hazel into the bowl, and then mix it in really well. The reason this bit can be tricky is because if you add too much, the fizzing will start, because water is what allows the citric acid and the baking soda to start reacting. So do just a little at a time, and if it starts fizzing, mix it in well till it stops.
  4. You're looking to get just the right balance between wet and dry. If it's too dry, it won't stick together to make bath bombs. If it's too wet, well, it fizzes! The consistency you want a bit like damp sand – just wet enough that if you squeeze it in your hand, it just about forms a nice clump and stays clumped.
  5. Homemade bath bombsNow it's time to put the mixture into your molds.You want to pack the mixture in as tight as you can, that helps them keep their shape. You can use all kinds of molds for this – cookie molds, etc. If you want round bombs, then get some of those clear plastic balls that you get at Christmas – the ones you fill with candy and hang on the tree. They come in two halves, so they're easy to fill, just pack each half till it's slightly over-filled, and then press them together hard. Or squish them into balls by hand for that homemade look!
  6. Most of the time, you only need to leave them for a minute or two, and then you can tap them out of the mold. If you get some that crumble, just pack them back in the mold and try again. If they keep crumbling, squirt or spritz in a little water. Leave them overnight to dry, and you're done! Store them somewhere dry, if you don't use them immediately – a sealed container is good.

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