EN+ A1 certification allows a maximum of 0.7% ash by mass. Most commercial pellets sit at 0.5–1.2%. Running consistently under 0.6% requires control at four stages of the production line — here's how we do it.
Stage 1: Source selection
Not all sawmill waste is equal. Bark content is the single biggest ash driver. We reject any batch with visible bark exceeding 5% by weight. That alone eliminates most of the silica and calcium that would otherwise end up in the ash pan.
Stage 2: Hammer-mill calibration
Particle size distribution affects both die compression and ash liberation. We run a 4 mm screen on the hammer mill, targeting 80%+ particles below 3.5 mm. Oversize particles create voids in the pellet, lowering density and trapping mineral inclusions.
About the author — Zara Ali runs the Quality Assurance lab at NatureTech's Karachi pellet facility. She holds an MSc in Chemical Engineering and has been with the company since 2021.
