Castile soap alone makes a poor bubble bath, and it is worth saying so before you try. Here is the recipe that actually works, and the reason the extra ingredient is not optional.
Start with the honest part: pour castile soap into running water on its own and you will get a thin layer of bubbles that collapses in about two minutes. That is not a fault in the soap. It is what soap without foam boosters does.
Commercial bubble baths are built around synthetic surfactants chosen for one job: make foam, keep foam. Our Pure-Castile Soap has no artificial detergents, synthetic dyes or foaming agents in it, so the bubbles it makes are real but short-lived. The recipe below fixes that with one ingredient, and it is the difference between a disappointing bath and a good one.
For a standard tub:
Stir the glycerin into the soap in a cup first, then pour the mixture under fast-running warm water as the tub fills. Pouring it into water that is already still gets you far fewer bubbles. The falling water is doing the aerating.
A bubble is a film of water held between two layers of soap. It pops when the water in that film evaporates or drains away. Glycerin slows both, so the same bubbles last several times longer.
This is not a workaround for a deficiency. It is the same principle behind every long-lasting bubble solution, including the ones children blow through wands. Without it you are asking soap to do something soap does not do on its own.
Vegetable glycerin is sold in pharmacies and craft shops and costs very little. There is already USP vegetable glycerin in our soap, which is part of why it is gentle. The tablespoon you add is simply more of the same.
Run the water hot, then adjust. Warm water aerates better than cool. Fill with hot, add the mixture early, and add cold at the end to bring it to temperature.
Aim the stream. Position the mixture directly under the falling water rather than pouring it along the side of the tub.
Do not add oils. Bath oils, bath melts and rich carrier oils are the enemy of foam. Oil breaks the surface film that bubbles are made of. Pick one or the other in a given bath.
Hard water works against you. Minerals react with soap and cut foam. If your water is hard, you will need a little more soap than the recipe says, and you may never match a synthetic bubble bath. That is an honest limit, not a technique problem.
Dilute further. Start at 2 tbsp of soap for a child's bath rather than a quarter cup, and keep it out of their eyes. The soap is unscented and contains no essential oils, which matters here: many essential oils that are fine for adult skin are not appropriate for young children. Anything scented in this bath would be your addition, not ours.
Baby wash is one of the uses printed on our label, but a bubble bath is a longer soak than a wash. Rinse afterwards, and skip the bubbles entirely for anyone prone to urinary tract irritation. That advice applies to every bubble bath on the market, not just this one.
With glycerin, a decent head of bubbles that holds for most of a bath. Without it, a brief foam and then flat water. The soap cleans identically either way; glycerin changes the show, not the wash.
Mix what you need per bath. A pre-mixed jar of soap and glycerin keeps, but anything you dilute with water should be used within two to three weeks. There are no synthetic preservatives in this soap, and water is what introduces microorganisms.
Pure-Castile Soap, 64 fl oz → | More answers →
Yohan & Alex
Co-founders, Whole Naturals
For external use only. Keep out of reach of children. Discontinue use if irritation, redness or discomfort occurs.
