No two wood pellets are the same. There will be differences in color and length depending on the materials used and where the pellets were manufactured. The colors vary based on the use of hard wood vs soft wood. Wood pellets can range from light brown to dark brown, or even have a reddish hue to them. If the wood pellets are darker than black coffee then most likely they will have a higher ash content.
The length and overall size of a wood pellet is determined by the manufacturing process. Pellet stoves require that the pellets be between 0.25 inches and 1.5 inches. Raw material such as saw dust, lumber scraps, and wood chips are delivered to the pellet mills. All the raw material is then broken down to a uniform smaller size. Next the materials are run through a dryer drum to get rid of any moisture. Once the excess moisture is removed, the material is broken down to even finer pieces.
The finer pieces are put into a high pressure drum and sliced into the pellet shape. While in the drum, the sap in the wood materials heats up and helps mold the pellet pieces together. Once shaped, the wood pellets are put into a cooling tower to harden.
Your wood pellets will arrive in vented bags to keep any moisture from being trapped.