A psyllium husk purity grade states roughly how much of the product, by weight, is clean husk. In 99% grade almost everything is husk. In 85% grade a much larger share is other material, mainly light extraneous matter, kernel fragments and dust.
These are trade grades, not a legal standard. Two mills selling "98%" may test differently, so you need to define how purity is measured and back it with other tests.
How the grades are made
Milling the seed produces a mix of husk, broken kernel, fine dust and light fragments. Processors separate this mix with sieves, aspirators and air classifiers. Each extra pass removes more impurity and raises purity, but also loses some husk. That is why higher grades cost more to make.
- 99% grade: the cleanest fraction, typically for pharmaceutical products and high-end supplements.
- 98% grade: very common for supplements and pharma-related use, and widely exported.
- 95% grade: often used in food, bakery and general supplement products.
- 85% grade: lower purity, often for feed, some industrial uses and lower-cost products.
What changes as purity rises
Purity drives the properties buyers actually care about. As a general pattern, higher purity husk has a higher swell volume, lower light extraneous matter and lower total ash. It also looks paler and more uniform. The exact figures depend on the crop year, the seed and the mill, so ask for test results rather than assuming.
For background on the swelling test, see what swell volume is and what value to ask for. For the main impurity, see light extraneous matter in psyllium.
Why the label is not enough
Purity is usually tested by separating and weighing fractions, and the method varies between labs and mills. A supplier can also blend grades to hit a number on paper. Protect yourself by specifying a group of tests, not purity alone.
- Purity, with the test method named.
- Swell volume in ml per gram, with the method and soaking time.
- Light and heavy extraneous matter.
- Total ash and acid-insoluble ash.
- Moisture.
- Microbiology, and pesticide residues against your market's limits.
Choosing a grade
Pick the lowest grade that reliably meets your product's needs, and test it in your own process. A capsule maker may need 99% for fill weight and dose consistency. A bakery may be fine with 95%. A feed formulator may only need 85%. If your customer has a written spec or a pharmacopoeia requirement, that decides the grade for you.
Ask for samples of two adjacent grades from the same mill. Testing them side by side shows you what the price difference buys.
How we help
We test samples from several Unjha mills at an NABL-accredited lab against the same method, so grades are compared fairly. We then check that the shipped lot matches the approved grade before loading. Ask for a free sourcing review.