PATRICK L. TING (1), Fran Saunders (2), Gregory Casey (3), David Ryder (1)
(1) MillerCoors, Milwaukee, WI; (2) Miller; (3) MillerCoors, Golden, CO
Diatomaceous earth (DE), a filter aid, has been used by brewers
around the world to produce brilliantly clear beer. However, iron,
copper, and metals present in the DE can leach into the liquid and
deteriorate the beer flavor. Trace Fe or Cu and a trace level of oxygen
mediate free radical formation, analytically resulting in higher
ESR/PBN-T150 values correlating with the more rapid development of stale
flavors in beer. Brewers and brewing scientists around the world are
looking at alternative technologies to replace DE filtration, such as
Divergan HM or membranes. However, one stumbling block is the cost of
these alternative technologies. U.S. Patent 4,187,174 (Feb. 5, 1980)
disclosed that a treatment of diatomaceous earth filter aids with an
acid (inorganic acids, acetic acid, and oxalic acid) resulted in a beer
soluble iron (BSI) content of less than 0.01–0.005% (100–50 ppm). We are
developing a novel streamline treatment of DE with hop acids (such as
tetrahydro iso-α-acids) and H3PO4 during
filtration to prevent/reduce soluble iron in DE from leaching into beer.
This results in a lower ESR intensity increase versus normal DE
filtered beer, which leads to a better flavor-stable product.
Patrick L. Ting, who holds a Ph.D. degree in organic chemistry, is
currently working in Brewing and Research, MillerCoors, Milwaukee, WI.
His area of research is in hops and advanced hop product development,
including better understanding of the attributes of hops to improve hop
flavor and flavor stability, hop chemistry to enhance product and brand
performance, and applied hop science to improve product quality. He has
developed novel hop products and new hop technologies and is guiding the
company’s Watertown Hops Company facility to improve processes and the
quality of hop products.
