Extrusion is the manufacturing step that turns a wet mash of meals, water, vitamins, and binders into the dry, shelf-stable pellet that lands in your tank. It is also where most of the nutrient damage happens in cheaper fish foods.
Why temperature matters
Vitamins are heat-sensitive. Vitamin C and B-complex vitamins start degrading above 90 °C. Beneficial fatty acids oxidize. Astaxanthin loses potency. Conventional dry extrusion runs at 130 °C+ because it is fast and cheap.
Twin-screw steam extrusion runs cooler, with moisture introduced as steam to plasticize the dough rather than friction-heat doing the work. The result: shorter exposure to heat, lower peak temperatures, and most of the nutrient profile preserved into the finished pellet.
Twin-screw vs. single-screw
Single-screw extruders rely on raw friction to generate heat — that’s why they run hot. Twin-screw extruders use two interlocking screws that mechanically knead the dough as it moves. The kneading action does the work that friction would otherwise do, so far less heat is needed. It also gives a more uniform mix, which means every pellet across the batch has the same nutritional profile.
What you actually see in the pellet
Steam-extruded pellets have a denser cross-section than dry-extruded ones — closer to a solid lattice than a puffed honeycomb. Three things follow from that: (1) they sink predictably without dust, (2) they hold up longer in water before disintegrating, giving slow eaters more time, and (3) they release nutrients gradually rather than dumping them in the first 30 seconds.
The trade-off we accept
Steam extrusion is slower and more expensive per kilo of finished product. We make less in a given hour than a high-heat plant could. We accept that because every pellet that leaves our line is closer to the nutritional value the formula was designed to deliver.
Heat is cheap. Patience is what makes the difference.