Pre-refining Single Stone Mill

  • Slowly rotating disc for gentle milling on low temperatures
  • Flow rate up to 900 kg/hour
  • Fineness achieved
    1. 3 – 4% > 75 µm (nuts)
    2. 7 – 8% > 75 µm (cocoa nibs)
  • Low wear on the grinding disc ensures low maintenance costs, re-grinding of stones possible
  • Low energy consumption and low noise level
  • No increase of iron content
  • Clear selection


The stone mill contains a set of integrated hard cast iron pre-milling disks for transforming solid nibs (nuts, seeds, almonds etc.) into a course ground liquor. The nibs are ground between a pair of grinding stones of which one is stationary and the other rotates at a very slow speed. The material to be ground is led to the center of the pair of grinding stones. Here, the first grinding is effectuated. In the remaining grinding chamber specially grooved grinding stones effect the fine grinding. Due to the low peripheral speed of the grinding stones, a gentle grinding process is achieved with little abrasion. The grinding stones are made of Aloxite and have a long lifespan.

Pre-grinding methods

The mill is suitable for green, dried, roasted and alkalized nibs and has an integrated air suction system for further de-moisturizing of products.
The single-stone mill type CMG is used in the pre-grinding of cocoa nibs, in order to make cocoa liquor for cocoa cake or cocoa butter and cocoa powder. But also to grind nuts and seeds in order to make nut paste or nut butter, nut spreads, nut creams or nut oil and nut powder. Royal Duyvis Wiener offers different methods of pre-grinding and with our stone mills or beater blade mills, we will find the optimum solution for you specific requirements.


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Additional information


Cocoa Liquor Processing, Cocoa Nibs / Kernel Processing


Types Capacities [kg / hr]
Single-stone Mill type CMG 200 – 900