Psyllium husk 99% purity means that by weight 99% of the lot is psyllium husk and 1% or less is seed fragments, dust and other plant matter. Psyllium husk powder 40 mesh means the powder passes a 40-mesh sieve, with openings of roughly 0.42 mm. Both are claims that a laboratory can check, so ask for the test, not just the number.
The husk is the outer coat of the Plantago ovata seed. Unjha plants mill the seed and winnow the husk away from the kernel. Purity is a measure of how well that separation was done.
What does 99% purity actually measure?
Purity is a percentage by weight of husk in the product, with the balance being impurities. At lower grades such as 85, 95 or 98%, more of the balance is seed and dust. Purity grades from 85% to 98% lays out what each grade looks like.
The figure is only as good as the method. Plants usually measure it by sieving, air winnowing and hand counting of impurities in a sample. Ask for the method in writing and run the same test at an independent lab on a sealed sample.
What is the difference between purity and swell?
Purity tells you how clean the husk is. Swell volume tells you how well it works. It is measured as the volume that a gram of husk reaches after absorbing water, in millilitres per gram. A husk can be 99% pure and still swell poorly if the seed was old or poorly processed.
If your product depends on gelling, put a minimum swell volume and a viscosity or gel test in the spec as well as purity. Do not rely on purity to carry both.
What does 40 mesh powder mean?
Husk powder is made by grinding the husk and screening it. A 40-mesh powder passes a sieve of about 0.42 mm; finer grades such as 60 or 100 mesh pass smaller openings. Finer powder disperses and mixes more smoothly but can clump if poured onto water, while coarser powder is easier to handle and blends in dry mixes.
As with any mesh claim, name the sieve standard and the percentage allowed to be retained. Mesh sizes available for husk powder shows the range suppliers offer.
What should be in the full specification?
Beyond purity and mesh, add moisture, ash, swell volume, a heavy-metal limit, a pesticide residue limit for your market, microbiology and a foreign-matter limit. For food or supplement use, say so on the order, and confirm your market's rules on ingredients with your importer or regulator.
Cost depends on the seed crop, the purity, the mesh and the tests, so there is no useful figure to give; a quote follows a spec. For the full background, see psyllium husk from India: a sourcing guide.
How do you check a purity claim yourself?
A simple check on a received sample is to spread a measured weight on a dark tray and pick out seed fragments, black specks and stalk. That will not replace a lab test, but it shows quickly whether the claim is close. If it is not, stop and send a sealed sample to an independent lab.
Keep a retained sample from each lot, sealed and labelled with the lot number. If your customer complains months later, that sample is your evidence.
Next step
If you want the purity and mesh of a psyllium order written into a spec and verified, book a free sourcing review. We have lots tested before shipment and check the certificate against the goods.