Scaling chocolate refining with ball mills
When evaluating a ball mill, the real questions are: “Will I get the same taste and texture at production scale as I do in my trials?” and “How much energy will it take?”
As Roy Smith, food technologist at Probat, explains, the key is not just measuring fineness, but understanding what it takes to get there.
Energy defines the refining result
In ball mill refining, the process is based on continuous circulation through a chamber filled with grinding media. The product is pumped from bottom to top, and with each pass, particles are reduced further through friction between the balls.
But what matters in practice is not just the mechanism—it’s the energy behind it. During pilot trials, operators track starting fineness, final fineness and throughput, but the decisive parameter is energy input.
As Roy Smith puts it: “we want to know how much kilowatt is necessary to get this product to the right end fineness.”
Once that energy requirement per kilogram is known, it becomes the basis for scale-up. “Energy is always the same… the industrial line needs to use the same amount of energy.”
This makes energy the transferable variable between pilot and production—more reliable than time or machine size alone.
Keeping the process identical across scales
For this approach to work, the process setup must remain consistent. In systems such as the Wiener ball mill from PROBAT, the same core elements are used from pilot to industrial scale:
- a grinding vessel filled with steel balls
- a circulation loop
- and controlled pumping through the system
Because the principle remains unchanged, pilot results can be directly translated. Whether the product is recirculated through one mill or passed through multiple mills in sequence, the refining mechanism—energy input through circulation—stays the same.
In practice, this allows producers to calculate capacity, estimate power consumption and predict product behaviour before committing to full-scale equipment.
