lec7a - Hops Botany Humulus lupulus L. Commercial Use Hops...

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1 Hops Hops Botany Humulus lupulus L. Commercial Use Brewing Minor uses Antimicrobial Medicinal - hop pillows, teas, tonics The small, yellow lupulin glands near the stem of the hop bracts contain essential oils, alpha acids and other resins. Broad Classification of Cultivars Bitter Hops - focus is on alpha acid content rather than essential oil; typically in the 10%-16% alpha acid range Aroma Hops - focus is on essential oil rather than alpha acid; typically in the 3%-6% alpha acid range Alpha acid HO O OH HO O R R = short, usually branched chain hydro- carbon, e.g. iso-Pr, iso-Bu, sec-Bu What is an acid?
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2 What is an acid? A species that contributes H + to solution For organic acids most commonly this means compounds of the form R-COOH: R O O - H + R O OH Some other structures, including phenols, can also contribute hydrogen ions: OH O - H + Alpha acid ionization HO O OH HO O R HO O O - HO O R H + Photoperiodicity - a shift in day length from about 16 hours to about 14 hours triggers the production of alpha acid. The rather extreme day length of 16 hours does not occur close to the equator, but it happens at either 35- 55ºN or 35-55ºS latitude. Northernmost Chuvash, Russia Southernmost Tasmania Southern hemisphere nearest Equator - Zimbabwe Northern hemisphere nearest Equator - Myanmar World Hop Growing Regions (mainly 35-55º N or S latitude) Former and Present US Hop Growing Regions Former Present
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3 Kettle Hop Addition In a large majority of beers all of the hop materials used are added to the brew kettle. This contributes the bitterness
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lec7a - Hops Botany Humulus lupulus L. Commercial Use Hops...

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