Guar gum is a galactomannan — a long chain of sugars — extracted from the seed of the guar plant. It's a common thickening polymer found in everyday cooking, and it's a favorite in the bubble community for its unbeatable price-to-performance ratio.
How to use it
The key is hydrating it properly: disperse it in a small amount of water (sometimes with a splash of alcohol to keep it from clumping), let it sit, then blend it into the soap mixture. Poorly hydrated guar forms clumps that ruin the film.
Typical doses are small amounts per liter of water — overdo it and the mix turns thick and hard to work with. It performs especially well when combined with another polymer like PEO (see polydispersity). In the simulator you can try different amounts and instantly see how the score changes.