O-13
Advancements in diatomaceous earth processing reduces iron and other solubles to improve flavor stability and shelf life
Presenter: Peter Lenz, EaglePicher Filtration & Minerals, Reno, NV
Co-Author: Kimberly Walsh, EaglePicher Filtration & Minerals, Reno, NV

Filtration of beer with the use of diatomaceous earth (DE) filter aids has been the industry standard for several generations. New advances in the processing of DE make it possible to produce a higher-quality filter aid, which has reduced soluble ions, such as iron, arsenic, calcium, and sodium versus standard brewing DE. It is believed that iron in beer increases the potential for increased tannin formation. Increased tannin formation in beer creates a non-desirable taste and reduces the shelf life of many lighter-body beers. Therefore, this advancement in DE processing yields a more pure filtrate and could provide benefits to brewers interested in maintaining taste stability and shelf life. The reduction in soluble content can be measured in the beer by using standard ASBC testing methods, such as beer soluble iron (BSI). Most standard brewing DE grades have a BSI level of approximately 45 ppm. EaglePicher specialized brewing grades are available as low as 10 ppm. The impact of this difference is best measured using the following equation: Iron in final filtrate due to DE = Initial BSI specification × DE usage/Weight of beer per barrel. Assuming the average BSI levels above, and equal usage of approximately 0.30 lb/bbl. The final filtrate with a 10 ppm BSI will have a final impact on the beer of 11.5 ppb, while standard brewing grades at 45 ppm BSI will yield a filtrate with 51 ppb of iron, for a 77% reduction in iron. Other factors, in addition to the initial BSI of the DE, that affect the final iron levels in the polished beer are: contact time, suspension in the slurry tanks, cake, amount of filter media used per filtered barrel, pH, and temperature. Our newly developed DE grade for beer processing, also reduces overall filter aid usage in most circumstances, as we have demonstrated for the last two years at a variety of breweries throughout the world. EaglePicher is proud to have developed a product that will not only provide for reduced solubles but one that will also allow breweries to reduce their usage and increase operational efficiencies through increased throughput and extended cycle times.

Peter Lenz has received an M.S. and B.S. in mining engineering from the Mackay School of Mines in 1989 and 1979, respectively. He began his employment as mining engineer and has been with EaglePicher Filtration & Minerals for the last 15 years as the director of research and development. He has been working with breweries globally for the last 10 years and is member of the American Filtration & Separations Society.