FYI - There is a detailed article from 'Brewing Techniquies' magazine available online at http://www.brewingtechniques.com/librar
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on hop storage. http://www.brewingtechniques.com/librar
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"For optimum preservation of hops' valued qualities, they should be stored
as cold as possible (30 to -5 degrees F, or -1 to -21 degrees C) and away
There are hyperlinks within the article to tables on alpha acid loss for a wide range of hop varieties (incl. PoR) at various storage tempertaures, and mathematical formulae that can bbe used used to predict alpha acid loss.
References provided are:
(1) J.S. Hough, D.E. Briggs, R. Stevens, and T.W. Young, Malting and
Brewing Science, Vol 2 (Chapman and Hall, London, 1982).
(2) R.N. Skinner, R.P. Hildebrand, and B.J. Clarke, "The Effects of
Storage Temperature on the Stability of the Alpha-Acids Content of Baled
Hops," J. Inst. Brewing 83, 290-294 (1977).
(3) S.T. Likens, G.B. Nickerson, and C.E. Zimmerman, "An Index of
Deterioration in Hops (Humulus Lupus)," American Society of Brewing
Chemists Proceedings (American Society of Brewing Chemists, St. Paul,
Minnesota, 1970). 68-74.
(4) ASBC Methods of Analysis, 8th ed. (American Society of Brewing
Chemists, St. Paul, Minnesota, 1992).
(5) Gail Nickerson, personal communication, 1993.
(6) C.P. Green, "Kinetics of Hop Storage," J. Inst. Brewing 84, 312-314
(7) A.J. Rehberger and L.H. Bradee, "Hop Oxidative Transforms and
Control for Beer Bitterness," MBAA Technical Quarterly 12 (1), 1-8
(8) Hop Variety Specifications (Hopunion USA, Yakima, Washington,
(9) J. Wain, C.D. Baker, and D.R.J. Laws, "Deterioration of Pelleted Hop
Powders During Long-Term Storage," J. Inst. Brewing 83, 235-240
Over to you Vanessa.