Weigh the glycerin and carrageenan into a small heat-resistant glass measuring cup.
Whisk thoroughly to combine.
Add the surfactants and fragrance, stirring until uniform.
For the water and dye: weigh the distilled water and dye into a beaker or glass measuring cup. You are unlikely to be able to weigh out the dye due to the very small amount; what I did was weigh about half the water into the measuring cup, and then dip a clean spoon or glass stirring rod into the bag of dye so there was just a tiny amount on it, and then swished that spoon around in the weighed-out water before topping it off to a full 28.7% distilled water.
Add the citric acid to the coloured water, and stir to combine.
Combine the water and surfactant mixtures. Stir gently to combine, cover, and leave to thicken and dissolve for an hour or so (overnight is also very convenient!).
Once the mixture has thickened and is uniform (you’ll need to give it another stir after it sits to ensure everything is well mixed).
Weigh 2g product and 18g distilled water into a small bowl or beaker and whisk to combine (wondering why?).
Check the pH with your pH meter/strips.If your ingredients are all pretty similar to mine, it should fall between 4.1–4.4, and that’s great!
If the pH is above 4.5 or lower than 4, you’ll need to adjust it.
Once we’re sure the shower gel has the proper pH all that’s left to do is transferring it to our packaging.
I used a 120mL (4 fl oz) bottle. Use as you would any shower gel. Enjoy!
