Define what smooth means
A powder can disperse without visible lumps yet still feel gritty or become too thick. Assess wetting, clumps, mouthfeel and viscosity separately. Set the target for the drink you are developing before selecting a grade.
Compare processed formats
Agglomerated psyllium groups smaller particles into larger structures. Instantised psyllium describes a format developed for preparation and dispersion. These terms do not establish the same particle structure, composition or performance for every supplier.
Request the specification and processing details, then compare the candidate with a reference under the same conditions. Improved initial dispersion does not mean the psyllium stops swelling or forming a gel.
Use a repeatable trial
Record the fibre amount, liquid volume and temperature, addition order, mixing time and equipment. Check visible lumps after mixing and viscosity through the expected drinking period. Include the full recipe: proteins, acids, sweeteners and minerals can change the result.
If the intended preparation is spoon stirring, test spoon stirring. A high-shear laboratory result will not describe that experience on its own. Establish acceptance criteria before choosing a material for larger trials.