This grade is an evolution of Ahlstrom 613 for use in the beer industry. This is a filter paper with an extremely low iron and nitrogen content for the analysis of protein in beer.

Standard qualitative filter papers are suitable for quadrant folded or gravity flow applications. These grades contain a high level of alpha-cellulose that provides high purity but will weaken when wet. The inherent strength of standard (untreated) grades does not pose a problem when they are used in routine quadrant folded applications. We do not recommend these grades for use in vacuum work or when wet handling is required.