Glycerine

Glycerine, also called glycerol, is a clear, odourless liquid widely used in personal care, pharmaceutical and formulation products.

In your DIY toolkit, it has one particularly useful job: helping Xanthan Gum mix properly.

Xanthan Gum hydrates almost instantly when it touches water. If you tip the dry powder straight into a liquid, the outside can gel before the inside gets wet, creating stubborn little lumps.

Mix it with Glycerine first and the story changes. The thick liquid coats and separates the Xanthan Gum particles without hydrating them. When water is added afterwards, the particles can disperse and hydrate more evenly, creating a much smoother finished product.

Glycerine is also a humectant, meaning it attracts and holds moisture, which makes it particularly useful in hand wash, body wash and other recipes used on skin.

It isn't the thickener
Glycerine helps Xanthan Gum disperse, but Xanthan Gum is what actually creates the thickness and gel structure.

Use them together
A useful starting point is around 3–4 parts Glycerine to 1 part Xanthan Gum. Mix them into a smooth paste before adding your water-based ingredients.

It isn't a preservative
Adding Glycerine does not make a homemade water-based product indefinitely shelf stable. Make sensible quantities, keep bottles clean and remake them when needed.

A little goes a long way
You generally need only a small amount in each recipe, particularly when its main role is dispersing Xanthan Gum.

Storage
Keep tightly closed in a cool place away from direct sunlight.