<html><head><title>Supercritical Fluid CO2 Extraction and Oil Separation Search Engine Series | Beer Hops | Hop Aroma Component Profile and the Aroma Unit 001</title></head><body> <meta name='description' content=' Information Publications | Publications Search Engine | On Demand PDF Document Searches '/> <meta name='keywords' content='beer hops, cannabis-extraction, hops-oil, Supercritical CO2 Fluid Extraction, Apeks-Supercritical, Eden-Labs, Waters-Supercritical, Cannabidiol-Hemp-Cannabis-Cannabinoid-Cannabis-Sativa-CBD-Marijuana-terpenes' /> <a href="http://www.infinitysupercritical.com"><img src="logo.jpg"alt="Infinity Supercritical LLC" width="265" height="75"></a></p> <BR> Publication Name: Hop Aroma Component Profile and the Aroma Unit<BR><p><b>Supercritical Fluid CO2 Extraction and Oil Separation Search Engine Series </b></p><p>Beer Hops search was updated real-time via Filemaker on: </p><script type="text/javascript"> tmonth=new Array("January","February","March","April","May","June","July","August","September","October","November","December"); function GetClock(){ d = new Date(); nday = d.getDay(); nmonth = d.getMonth(); ndate = d.getDate(); nyear = d.getYear(); if(nyear<1000) nyear=nyear+1900; document.getElementById('clockbox').innerHTML=""+tmonth[nmonth]+" "+ndate+", "+nyear+""; setTimeout("GetClock()", 1000); } window.onload=GetClock; </script> <div id="clockbox"></div></p><a href='../index.htm'> Beer Hops Contents List </a><BR><BR><a href="supercritical-carbon-dioxide-extraction-of-hop-pellets-008.htm">Previous Page View</a> | <a href="hop-aroma-component-profile-and-aroma-unit-002.htm">Next Page View</a><p>Search Completed. <BR> Publication Name: Hop Aroma Component Profile and the Aroma Unit<BR> Original File Name Searched: perfil_de_lupulos_aromaticos_e_unidade_de_aroma.pdf<BR> Page Number: 001<BR><BR><TABLE border='1' style=width='1200'><TR><TD valign='top'> <b>PDF Text:</b><BR><BR><span style="" >Hop Aroma Component Profile and the Aroma Unit<br/><br/>Gail B. Nickerson, Department of Agricultural Chemistry, Oregon State University, Corvallis 97331-6502, and Earl<br/><br/>L. Van Engel, Blitz- Weinhard Brewing Company, Portland, OR 92709<br/><br/>ABSTRACT<br/><br/>More than 250 essential oil components have been identified in hops by capillary gas chromatography. The hop aroma component profile (HACP), quantitatively measured as nanoliters per gram of hops (1 ppm, v/w), is composed of 22 of these hop oil compounds that have been reported to affect hop aroma. Similar steam distillation methods were used to measure the HACP of hops, wort, and beer. HACP analysis of seven commercial hop pellet samples (Cascade, Chinook, Cluster, Hallertau, Saaz, Tettnang, and Willamette) were made. It was found that within one variety, the total HACP could vary by as much as 50%. Subsequently, the hop aroma unit, which consists of 1 nl/g (1 ppm, v/ w), the sum of the 22 hop oil constituents, was conceived. The hop aroma unit can be used as a standard measure of hop aroma content, just as the bitterness unit is used to measure bitterness.<br/><br/>Keywords: Aroma, Hop, Hop oil<br/><br/>Quantitatively, hops are a minor ingredient in brewing. Nevertheless, the contribution of hops to the flavor and aroma of beer is important. The relationship between the amount of a-acids in hops and bitterness in beer was elucidated many years ago. During the boiling of wort, a-acids are converted to bitter iso-a-acids. The measurement of bitterness units (BU) in beer is a test used worldwide, even though it is not specific for iso- a-acids (1). A number of factors affect the utilization of a-acids, but generally, the higher the a-acids content in hops, the fewer hops it takes to achieve a certain bitterness level. Kettle or &quot;bittering&quot; hops are added at the beginning of wort boil to achieve maximum use of a-acids, or preisomerized extracts are added after fermentation. Because each brewery has different utilization rates of a-acids to iso-a-acids (11), each brewery adjusts hopping rates based on the a-acid contents of the hops they use and the BUs specified for their product.<br/><br/>Research on the hop oil compounds with capillary gas chroma- tography (GC) has led to the identification of 250 compounds in the essential oil of hops. A number of these compounds, i.e., humulene oxidation products, have been isolated or synthesized and used in flavor evaluations (13,14,21,24). In addition, a great deal of work has been done on the detection of hop oil constituents in beer (4,10,16,18,20,23). Unfortunately, no consensus has been reached on which constituents contribute the most to a &quot;hoppy&quot; aroma in beer. Murray et al suggested that the proportion of alcohols to ketones influences the nature of late-hop flavor (19). They also have found varietal differences in beers brewed with single hop varieties (7-9). In England, the practice of dry hopping has led to the postfermentation addition of hop oil isolated from liquid carbon dioxide extracts (6). The amounts and composition of such extracts can be controlled fairly easily (27). Dry hopping seldom is done in the United States; instead, &quot;aroma&quot; hops generally are added just before the end of wort boil. The late addition of aroma hops is based on the fact that a considerable loss of hop aroma occurs during wort boiling because of the steam distillation of volatiles. Shorter boiling times increase the amount of hop oil constituents in the wort.<br/><br/>The major constituents of hop essential oil are monoterpenes and sesquiterpenes, and the proportions of these compounds are valuable in varietal identification (12,28), although they seldom are detected in beer (16,17). Oxygenated compounds present in hops have been detected in beers (22,24,29), and fermentation products from hop oil constituents also have been identified<br/><br/>* 1992 American Society of Brewing Chemists, Inc.<br/><br/>(20,26). Foster and Nickerson proposed measuring the amounts of 19 hop oil compounds per gram of a-acid as an expression of the potential aroma contribution and called this &quot;Sigma&quot; (5). The compounds were divided into three groups, excluding major hydrocarbons, consisting of floral-estery compounds, piney-citrus compounds, and humuleneand caryophyllene oxidation products. The Sigma measurement presumes that the hopping rates will be adjusted according to a-acids content and that the aroma deriving from the hop oil constituents will vary depending on variety and storage. In this article, we propose that the required volume of hop oil constituents per gram of hops should be used as the criterion for adjusting the hopping rates of aroma hops and that the a-acids content should then be a secondary consider- ation. The list of hop oil compounds that comprise Sigma was modified to include the 22 compounds listed in Table I as the basis for a hop aroma component profile (HACP). Instead of cadinene(s), the individual compounds are given&mdash;a-muurolene, /3-selinene, and A- and y-cadinene. Nerolidol was deleted because it is difficult to detect in hop oil and is not really an oxidation product of humulene or caryophyllene. In Table I, the compounds in parentheses usually are not detected in fresh hop oil, at least under our experimental conditions. One aroma unit (AU) is defined as 1 ppm (nanoliters of oil per gram of hops or microliters per liter of wort and beer) of the sum of these compounds. This is analogous to the BU measurement in beer.<br/><br/>This article emphasizes the analytical procedures used to measure hop oil constituents in hops, wort, and beer and the effects of maturation, storage, and variety on the HACP. A subsequent article relates the application of these measurements to brewing (30).<br/><br/>EXPERIMENT AL<br/><br/>Hops and Hop Products<br/><br/>Fresh-picked green hops, dried and stored samples from the Oregon State University (OSU) world hop collection, and com- mercially prepared hop pellets all were analyzed. Hops usually are analyzed after they have undergone considerable processing (picking, dying, baling, and perhaps pelletizing or extraction). The analysis of hand-picked green samples provides information on the effects of picking, drying, and baling on the hop oil composition. Hop cones were hand-picked from sidearms collected from commercial hop yards. The green samples were analyzed for dry matter, oil, and resin content and composition.<br/><br/>TABLE I<br/><br/>Hop Aroma Component Profile Constituents<br/><br/>77<br/><br/>Humulene and Caryophyllene Oxidation Products<br/><br/>(Caryolan-l-ol)a Caryophyllene Oxide (Humulene Diepoxide A) Humulene Diepoxide B (Humulene Diepoxide C) Humulene Epoxide I Humulene Epoxide II Humulene Epoxide III Humulenol II<br/><br/>Humulol<br/><br/>Floral-Estery Compounds<br/><br/>Geraniol<br/><br/>Geranyl Acetate Geranyl Isobutyrate Linalool<br/><br/>Citrus-Piney Compounds<br/><br/>A-Cadinene 7-Cadinene (Citral) Limonene (Limonene-lO-ol) a-Muurolene (Nerol) /3-Selinene<br/><br/>oil from fresh hops<br/><br/>&quot;Compounds not usually detected in steam-distilled are in parentheses.<br/><br/></span></TD><TD valign='top'><b>PDF Image: Hop Aroma Component Profile and the Aroma Unit</b><BR><BR><img src='../images/hop-aroma-component-profile-and-aroma-unit-001.jpg' alt=' Supercritical Fluid Extraction Hop Aroma Component Profile and the Aroma Unit Page 001 ' style='margin-left:20px;border-style:solid;border-width:1px;border-color:black;'> </TD></TR></TABLE><table border=1px solid blackstyle =width:50%> <tr> <td><b>Supercritical CO2 Fluid Extractor - Oil Extract Using Infinity Supercritical CO2 Extraction System </b>- Botanical CO2 Extraction System - <a href="http://www.infinitysupercritical.com">Go to website</a> </td> </tr> </tr> </table><p> </p> <script> (function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){ (i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o), m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m) })(window,document,'script','//www.google-analytics.com/analytics.js','ga'); ga('create', 'UA-59168860-1', 'auto'); ga('send', 'pageview'); </script> <address> <p>Search Engine Contact: <a href="mailto:greg@infinitysupercritical.com?subject="Decarb">greg@infinitysupercritical.com</a></p><p><br /></p> </body></html>