The PolarFit™ ultra-fine-grinding mill reduces hard-to-grind materials to smaller particle sizes than conventional impact mills. This system can generate consistent yields of particles between 45 and 250 microns (60 and 325 mesh), and in some cases as small as 10 microns. The product is ideal for cryogenic size reduction of a wide range of materials, including nutraceuticals, spices and other food products. The system uses a combination of size reduction mechanisms, including impact, attrition and particle-particle collision. The unit has an adjustable grinding gap, allowing the production of particle sizes from ultra-fine to coarse.