How to Make Shower Steamers: Mixing, Packing and Drying

Quick answer: sift 3 parts baking soda and 1 part citric acid with a little cornstarch, mix in the scent, and spritz witch hazel or alcohol until a squeezed handful holds its shape. Pack it hard into molds, let the steamers dry all the way through, and store them airtight. In the shower, put one where it gets splashed, not under the spray.

The method

1. Weigh the baking soda, citric acid and cornstarch.
2. Sift them together into a wide bowl, and set a spoonful aside in case the mix gets too wet later.
3. If you’re using menthol, dissolve the crystals in a little rubbing alcohol. Wear gloves.
4. Add the essential oil and the menthol and work them through with gloved hands.
5. Spritz witch hazel or alcohol a little at a time, mixing between sprays, until a squeezed handful holds its shape.
6. Pack the mix hard into the molds, overfilling a little and pressing it down.
7. Let the steamers dry until they’re hard all the way through.
8. Store them airtight.

A small test batch is 300 g baking soda, 100 g citric acid and 25 g cornstarch. Menthol and essential oil only go in at the rate your supplier gives for this kind of product. The shower steamer calculator scales the recipe to your molds and turns the supplier’s rate into grams.

What you need

How a steamer differs from a bath bomb

A shower steamer runs on the same reaction as a bath bomb. Baking soda and citric acid sit together quietly until water gets to them, then react and give off carbon dioxide. The bath bomb guide explains that reaction and why moisture, in the bowl or in the air, causes most of the trouble.

A bath bomb goes into a full tub and is meant to fizz away in a few minutes. A steamer sits on the shower floor getting splashed, and it has to keep giving off scent for the length of a shower, so it’s made harder and drier:

• A 3:1 ratio instead of 2:1. Each steamer has less acid in it, so there’s less to react at once and the fizz is gentler.
• Cornstarch. It doesn’t react. It sits between the powders that do, and it helps the steamer set hard.
• Firm packing. A loosely packed steamer falls apart the first time water hits it.
• No carrier oil. A steamer isn’t meant to touch your skin, so there’s nothing to moisturize.

Mixing and packing

Dissolve the menthol before anything else. Menthol dissolves in alcohol but hardly at all in water, so crystals stirred straight into the powder stay as hard little specks. Put them in a small glass dish, pour in just enough rubbing alcohol to cover them, and stir until they’re gone. Keep your gloves on, keep your face back from the dish, and open a window, because the vapor is strong. That alcohol counts toward your binder, so you’ll need to spritz less afterward.

Spritz a little at a time. Spray a few times across the top, mix with your hands, then spray again. A fine mist spreads the liquid evenly. A heavy squirt soaks one spot, and that spot starts to fizz.

Squeeze a handful and open your hand to see where you are:

• If it falls apart, it’s too dry. Spritz again.
• If it holds its shape and breaks cleanly when you poke it, it’s ready.
• If it feels wet, sticks to your glove, or you hear a faint crackle, it’s too wet. Stop spritzing and mix in the spoonful of dry mix you set aside.

Rubbing alcohol evaporates faster than witch hazel and sets off less of the reaction, which helps on humid days. Witch hazel is a bit more forgiving to work with. A lot of makers use alcohol for the menthol and witch hazel for everything else.

Overfill each mold, press the mix down hard with your fingers or the back of a spoon, then press again and scrape the top flat. Rigid plastic molds should be flipped and tapped out right away. Leave steamers in silicone molds until they’re firm. A tablet press packs harder than fingers can and gives you the most even steamers.

Why shower steamers crumble

Most crumbly steamers weren’t packed hard enough. They look fine in the mold and fall apart when you lift them out. Overfill and press harder.

The next most likely cause is a mix that was too dry. If your squeezed handful only just held together, the steamer will only just hold together too. Spritz a little more next time.

A steamer that comes out of a silicone mold while it’s still damp inside has no strength yet. Leave it until pressing the top doesn’t dent it.

If a steamer was hard and has gone soft or crumbly since, it pulled moisture out of the air. Store them airtight as soon as they’re dry.

And a steamer that puffed up in the mold has already used up some of its reaction. Once it dries it’s often crumbly and weak. Use less binder next time.

You can sometimes save a batch that won’t hold together by breaking it up, adding a spritz, and packing it again. If it has started to fizz, you’re usually better off starting over.

Drying and storing

Bramble Berry’s shower steamer instructions give several hours to overnight for drying, and a humid room takes longer. A steamer is ready when it’s hard all the way through and doesn’t feel cool. A damp one feels cold because the liquid is still evaporating.

Don’t wrap them before they’re dry. Sealing a damp steamer traps the moisture, and it can go soft, swell or stick to the others in the container.

Once they’re dry, put them in an airtight container or wrap them one by one. Menthol and the lighter parts of essential oils evaporate easily, so the scent fades before the fizz does. Make batches you’ll use or sell within a few months.

How to use a shower steamer

Put it on the shower floor in a corner, or on a shelf or soap dish, where water splashes it but the spray doesn’t hit it directly. The splashing sets off the fizz slowly, and the steam carries the scent up.

Right under the spray, a steamer dissolves in a minute or two and all the scent comes out at once. Out of the spray, one can last a whole shower. If there’s some left afterward, set it on a draining dish so it isn’t sitting in a puddle until next time.

Menthol and who should skip it

Menthol is what gives a steamer that cool, clear-your-head vapor, and it’s the ingredient to be most careful with. There’s no official usage limit for menthol in shower steamers, so use only the rate your menthol supplier documents for this kind of product.

Over-the-counter vapor rubs that contain menthol tell people to ask a doctor before using them on children under 2 or on anyone with asthma. Treat a menthol steamer with at least the same caution, and put that on the label. If there are young children in the house, leave the menthol out. The calculator page has the full safety notes, including why steamers should be sold for their scent and not as a cold remedy.

Other problems

Frequently asked questions