Normally, roller processing can achieve polishing accuracy of 0.6~0.8μm, polishing processing can achieve 0.4~0.6μm, and electropolishing can achieve 0.3~0.4μm.
It is well known that the size of yeast is about 6-10μm, and roller processing is sufficient to prevent contamination of yeast. However, the size of bacteria is between 0.7-4μm, so Roller processing alone is not enough, and fine polishing is required to prevent bacterial contamination from occurring.
Every welded part and port needs more attention to polishing test, because these areas are very easy to be contaminated.
Brewery Equipment uses polishing testing machines to ensure we give a qualified fermenter.
Now we use acid washing for our inner tanks and the accuracy can reach between 0.3~0.5μm.