By far the best bath bomb recipe and instructions I found in my search are given by Brenda Sharpe (thank you Brenda!). So go there and read those and look at great the photos. Ok? Ok. She mentions the need to keep the bath bomb mixture as dry as possible, but I live in a very damp climate. My first few attempts failed pretty miserably because of this. The problem is that the instructions call for you to mix all the wet ingredients together, which is great, but since my baking soda is pretty well moist without me adding anything to it, none of my skin-softening oils or yummy smelling essential oils were making it into the bomb either. So I made a few changes to the process. But first we must discuss a few things. Please remember everything contained here is my opinion or based on my personal findings and preferences. Use at your own risk. I haven’t hurt myself yet.
on where to get the ingredients
Baking soda is baking soda, you can get it in any grocery store. Epsom salts you can buy in any drugstore, in the medicinal aisles — it usually comes in a cardboard quart or pint milk container, somewhere around with the rubbing alcohol and bulk petroleum jelly. I have gotten essential oils of peppermint and rosemary from Majestic Mountain Sage, and From Nature With Love has been recommended to me. A quick warning, I bought a few oils online that I wasn’t happy with. Best bet is to buy essential oils from a local natural foods store that you can sniff first. They may be a little bit more expensive, but I find that it’s worth it. Mail order essential oils are best for hardcore soapmakers who are using ounces of essential oils at a time. Citric acid is where you’ll probably have the most trouble. I have been getting mine from Majestic Mountain Sage, I buy the 5lb, the smaller container goes surprisingly quickly. I haven’t had any luck finding it in stores, though I hear that you can find it in larger quantities for a good price at brewing and winemaking supply stores. The nut oil that you choose can be found in the cosmetics section of natural foods stores, or from Majestic Mountain Sage, I haven’t tried using any oils that you might find in the specialty section of cooking oils, although I have seen a number of recipes that call for nothing more than olive oil, so I suppose it’s up to you. Also see the supplies list at the Toiletries List.
It is used in many bath bomb recipes to make the bombs float, however I have read that corn starch can exacerbate yeast infections and can interfere with skin conditions. I have not found corn starch as an ingredient in any commercial bath bombs and, going upon the assumption that that is why, I leave it out. It’s true that without it the bombs are less likely to float, but you know, ack. Mine seem to float, or rather try to launch themselves right out of the water, the fizzing is so strong.
Turns out I was wrong. Wrong wrong wrong wrong. Commerical producers apparantly don’t use corn starch because it is more expensive, and cornstarch is fine for you, it’s actually great for you skin. That stuff about yeast infections I did indeed read a few different places, but let’s just assume they were wrong as well, wrong and paranoid. I’ll adjust the recipe as soon as I make a new batch. Which, sadly, could be a while since my current place has a small, shallow, miserable tub.
a note about salts
I use epsom salt because it’s cheap and there isn’t enough in the recipe to justify using expensive bath salts. Some recipes I’ve found are a bit unclear about what type of salt you’ll want. It’s best to stick with either Epsom salt or a sea salt intended for use in bathing. From what I can tell cooking salts that have been iodized will be drying to your skin.
a note about the molds
I also use clear plastic snap-together Christmas ornaments to mold the bombs. I got them from Craftopia when they were still around (they had three sizes), and found some at a local craft store, you can also buy a dozen 57mm (a good bath bomb size) here at the Oriental Trading Company. They do not produce perfect spheres, you can usually see the imprint of the seams in the finished bomb. If you’re striving for perfect spheres (I do not suggest this) I have heard a suggestion of using a meatball shaper (of which I have yet to actually find in existence), and I have found good sized (2″ to 3″ diameter) metal molds which come in clean half spheres at Sur La Table (I didn’t know what they were for until I saw an ice cream bombe spread in a Martha Stewart and there they were!), although they currently don’t have one on their Sur La Table. The ornaments also come in shapes (usually Christmas ornament related like bells, or hearts). You can also use any candy mold, I read people have a lot of success at this and that the bombs show shape very well, or pretty much anything else that makes a pleasing shape and seems like it would unmold easily enough. Be aware, that the mixture does scratch the plastic of the molds I use, so if you’re thinking of using an object near and dear, test it for scratchability first. Also keep in mind that you will need to apply a significant amount of pressure, so make sure whatever you use is up to this.
a note about scents
I prefer essential oils. I have purchased a few fragrance oils online and am consistently disappointed with the quality. What was I expecting? In one particularly bad incident I had to go to bed stinking of very fake chemical raspberry because it would not wash off. Fragrance oils may work great for soaps, but I don’t recommend them for bathing. I feel so naive.
add togther baking soda, epsom salt and citric acid in a collender to sift together
1 cup baking soda
1/2 cup citric acid
1/2 cup epsom salt
2 1/2 tablespoonss grapeseed, sunflower, or almond oil (or any nut oil is good)
3/4 tablespoon water and liquid glycerin
1/2 teaspoon or so essential oil (2.46 ml)
a good dust mask
I first measure out the baking soda into my work bowl (I use a large, cheap plastic one) and drop the essential oil and grapeseed oil directly into it, and mix until combined, it’ll look fluffy. (If you are making a large amount, you may want to take some baking soda into a smaller bowl, mix in the oils, then add that back to the larger bowl and mix in well.) If you’re not fond of bath oils leave out the nut oil at this step.
taking a little out to add grapeseed oil and essential oil, in this case peppermint and rosemary
when added back to mixture and whisked in the misture appears crumbly
it is ready when it holds when you press it togther
If you’re going to add color now is the time to do it. I have only experimented with small amounts of food colorings, not yet any dry pigments. If you’re going to go this route remember, make sure the food coloring doesn’t contain sugars, for the same reason we’re avoiding corn starch (see note above). I take a smallish amount of the mixture and separate it into a smaller bowl. Drop the coloring in a few drops at a time and mix, it should disperse after a while, make the color more intense than you intend it to be for the finished product. When it’s mixed, add it back to the mixture in the bowl and whisk until evenly dispersed. This will probably not be enough coloring to affect the color of the bath water itself. I’ll be looking into pigmenting the water in a little bit, or see the notes at the end of these instructions.
molding: step one
The citric acid and epsom salts will probably come in a fairly chunky granulated form, you’ll want to get them finer, about the consistency of superfine baking sugar or a heavy powder. I run mine through a coffee grinder I reserve for this purpose. Most of the bath bomb recipes I’ve found keep to a 2:1:1 baking soda:citric acid:salts ratio, which seems safe. But this isn’t baking so the measurements can be sloppily approximate without ending in disaster. When ground to a powder the citric acid will float in the air and make you cough (well, it makes me cough), use a mask and keep the area well ventilated. Whisk or sift the dry ingredients together really well to get the citric acid dispersed evenly throughout.
[update: see notes from 06.23.01 below regarding this step.]
I bought a few tiny spray bottles from Sunburst bottle which I use to moisten the mixture. I pour the oil/glycerin/water mixture into this and shake it before spraying. I usually only need two squirts to get the mixture to a moist crumbly stage at this point. I whisk the mixture while spraying to keep things moving. It’s very true that if you get it too wet it will set off the reaction even if it doesn’t appear to. As a result the bomb will not fizz when you’re ready to use it. It sort of crumbles in the bath, it’s not very pleasant.
I mold the balls as Brenda Sharpe instructs — it took me a little bit of practice to get it so that the balls didn’t just crumble in half, I fill each half of the ball, pat it in lightly, stack more on top of each side and push them together pretty hard. I let them sit for a few moments in the mold then unmold them veeeery carefully (don’t twist!) by allowing them to fall out of the mold one half at a time. I set on a clean kitchen towel, and put another one on top. This seems to keep them dry enough. If they begin to react you’ll see little, well, warts appear on the surface, eeek. A fan running in the room often helps this. I let them dry wrapped loosely in towels for at about a day. Some people put them in the oven. Some people sort of “cure” or harden the outer layer by spritzing them with witch hazel. Neither of these appears to work well in my climate. Sigh.
I let it set molded for a few moments, then carefully let it fall out of the mold one half at a time
I bought a tiny mold which works great for what mixture may be left over
finished bath bombs, the large ones the size of a large plum or small apple
the bombs will dry wrapped in the towel and placed in a dry room for about a day before I wrap in tissue paper, then plastic wrap until ready to use
Now, use soon! They don’t keep long, and you might end up with something that will not fizz at all if they grow stale. Be aware that if you added bath oil to the bomb it will leave the surface of your tub slippery, so be very careful. If you’re mailing to a friend be sure to instruct them as such — when shipping I find it’s nice to wrap in clean paper, then plastic over that.
I added these instructions when giving as a gift:
instructions for use:
1. fill tub full of yummy warm water
2. gather beverage (something hot and coffee-like is nice), reading material, and various bath accessories of your choice
3. tell everyone around you who is making noise to shut up for a little while
4. place self in bath
5. don’t forget to have a towel within reach so you don’t get your reading material wet
6. drop in bath bomb – it will fizz
8. now, isn’t this nice?
9. music or NPR is also good
* will not explode, i promise!
bath bomb ingredients: baking soda, citric acid, epsom salt, sunflower oil, glycerine, water, peppermint essential oil, rosemary esential oil
some things I have wanted to try but haven’t, yet
- making bombs of layers of color
- putting rose petals or calendula petals or peppermint leaves (warning: messy post-bath clean up)
- using a dried colorant from Sunfeather or something like Tub Tints to either color the bath bomb or hide in the bomb as a “surprise! your bath is turning green” type of thing, but colorants which will not color the skin!
some things I have tried and have failed miserably at
- I had this grand idea that I would hide entire gift sets inside of super large bath bombs. I could fit a small tightly folded washcloth, a small rubber ducky, some of those sponge pills, a small glycerin soap and a nail brush which would pop to the surface as the bomb worked away. Problem: it won’t hold, it really won’t, a bomb that big won’t hold even with nothing inside of it.
- hiding other things inside, namely, a collection of foam letters or number that would pop to the surface. Problem: no matter what recipe I tried and what size bomb I tried, it won’t hold together because the foam letters have too much give to them.
- hiding small, hard things, like a plastic ring. I had some luck with this. However, as the bombs dry, often a chunk would develop cracks or fall off completely, exposing the secret inside, negating the entire point.
- my favorite idea I realize wouldn’t work before I even tried it: Making a bath bomb from a Mexican Sugar Skull mold and hiding a glycerin soap the shape of a brain inside! Either that or something involving baby head, brains or skulls. I’m still determined to make this work somehow. I’ll keep you posted.
Ummm.. what else? Don’t store the bombs in metal because the of the corrosive properties of the salt, avoid storing them in plastic zip-loc type bags or cellophane, I have heard reports that the plastic eats the scents, and a few mysterious reports of lavender essential oil going bad when stored in cellophane, and try to store them either sealed or in a dry area. Don’t use them if they look or smell funny, don’t run with scissors, call your mother.
A great place to learn more and get your questions kindly answered is the mailing list at Toiletries Listservice, instructions to sign up are on the first page. The site itself catalogs recipes and information about ingredients and safety. This is a very nice bunch of people who are eager to help and and have an immense collective knowledge, even if you’re a quiet lurker you’ll learn a lot.
For the sake of comparison I tried out some fizzballs I bought at Loft. It was nice, not very fizzy, and smelled to perfume-y for my taste. Oops, I just noticed one is supposed to use one ball for two baths. But the scent did stay longer than the bath bombs I’ve made using essential oils. Also, I like the addition of some oil for my poor poor skin.
The batch I made to take the pictures above was different in a few ways. I was feeling lazy so I ground the epsom salt and made it through only half of the citric acid before I gave up and just dumped the rest in. I’ll let you know of this affects how fizzy the bomb is when I get around to using one. When I added the bath oil (grapeseed oil in this case) I didn’t measure, just poured a bit in, and added about twice as much essential oil to see how that would work out. When that was added back to the mixture as a whole, it was ready to be molded, so I didn’t use any of the oil/water/glycerine mixture. Which is great because there is always the chance you will set the mixture fizzing. The mixture molded and unmolded without any problems, we’ll see if the bombs hold together.
I meant to attempt to make colored bombs, but like I said, I was feeling lazy.
update: This batch came out badly, in crumbs, yuck. I’ll try again.
One thing mentioned at Lush and by a few people is that if you have or make a bath bomb with botanicals in it but don’t want them sticking to you or your tub, you can stick the bomb in the end of an old nylon or some loose fabric (cheesecloth or guaze) and it will catch all the little buggers.
update Jan. 3rd, 2007
A whole lot of great bath bomb instructions have appeared on the internet since I originally made these. I encourage you to hop over to Excellent Living to get the free 48-page PDF guide to making bath bombs, see her articles about making bath bombs and try this basic recipe.