The Oxford Companion to Beer definition of
Smaragd (hop)
Smaragd (Hop) is an aroma hop developed largely as a Hallertauer Mittelfrueh derivative at the Hüll Hop Research Center in the Hallertau region of Bavaria, Germany. See hallertauer mittelfrueh (hop). Smaragd is the German word for emerald. Commercially, this hop is also known as Hallertau Smaragd. Its primary use is in Bavarian lagers and Belgian-style ales. Smaragd is grown almost exclusively in Germany, where it matures mid-late in the season. It has an average yield of roughly of 1,850 kg/ha (1,650 lb/acre), and it has good resistance to downy mildew, but only average to low resistance to powdery mildew. The hop keeps well in storage. The alpha acid rating of this hop is a moderate 4% to 6%, the beta acid rating 3.5% to 5.5%, and the cohumulone a very low 13% to 18% of the alpha acids. Regarding essential oils, this variety has about 20% to 40% myrcene, 30% to 50% humulene, 9% to 14% carophyllene, and less than 1% floral farnesene. The variety also has a relatively high level of linalool, 0.9% to 1.4%. Linalool is an essential oil that imparts a citrus or bergamot aroma to the beer. The bouquet and flavor of Smaragd is somewhat like that of Hallertauer Mittelfrueh, showing predominately fruity, hoppy, and flowery notes.
Bibliography
Steinhaus, M., W. Wilhelm, and P. Schieberle. Comparison of the most odour-active volatiles in different hop varieties by application of a comparative aroma extract dilution analysis. European Food Research Technology 226 (2007): 45–55.
Verband Deutscher Hopfenpflanzer (Association of German Hopgrowers). “The spirit of beer. Hops from Germany.” http://www.cob.sfasu.edu/csc/gharber/public_html/bb/hopfenm_engl.pdf/ (accessed October 27, 2010).