Hydration controls the experience
Fibre behaviour often begins with water. A dry powder may look simple, but the moment water arrives, the system changes. Particles wet, swell, float, sink, clump, disperse, thicken, or hold moisture depending on the fibre type and processing route.
Psyllium makes this visible. If the outer layer hydrates too quickly, it can form gel-coated lumps while the centre stays dry. In bakery, the same water-binding power can support structure or steal water from the dough. In a shake, it can create body or become too thick. Water is not a background detail. It is the first test of whether a fibre is usable.