A food and beverage company discovered a black residue on the surface of a newly fitted vessel. They tried to wipe the residue away and get rid of it using chemical cleaning techniques, but it kept reappearing.
They then employed a company to carry out an electrochemically based cleaning process. This solution, at first, appeared successful in removing the residue, but after a CIP and heating cycle, it reappeared, showing that it was never entirely gone.

Image Credit: Astro Pak Corporation
Solution
When the food and beverage company reached out to Astro Pak, the company thought that the residue was embedded metal particles and abrasives left over from the mechanical polishing procedures employed during manufacture, an issue that Astro Pak has solved for its clients in the past.
Astro Pak’s solution was to completely electropolish the vessel to see if this process would totally and permanently eliminate the residue.
Electropolishing involves using a DC current supplied via an electrolyte solution to dissolve the metal’s surface to a pre-determined depth (two to five ten-thousandths of an inch), thereby releasing embedded impurities and eliminating the work-hardened layer that develops during mechanical polishing steps.
The cleaned surface is, as a result, more characteristic of the base metal alloy and less likely to capture product or other impurities in the future.
Results
Astro Pak suggested a strict timeline of events to prevent any interruption to the client’s already tight production and testing schedule. The process ran efficiently within the time frame with full documentation and no safety issues.
Electropolishing the food and beverage company’s vessel allowed the residue to be removed. It also made the surface smoother and easier to clean so potential future contaminants would not stick to it.
Astro Pak’s expert and fruitful execution of this project led to an invitation to complete the processing of more vessels at the same food and beverage company.
This client selected Astro Pak over their competitors because Astro Pak has highly skilled personnel who use advanced equipment, chemistry, and process technology, stick to safety protocols, offer rapid response, provide excellent documentation, and can tackle the most challenging surface finish problems.
Astro Pak : Microscopic View of Electropolishing - Narrated
Video Credit: Astro Pak Corporation

This information has been sourced, reviewed, and adapted from materials provided by Astro Pak Corporation.
For more information on this source, please visit Astro Pak Corporation.