<html><head><title>Supercritical Fluid CO2 Extraction and Oil Separation Search Engine Series | Beer Hops | FUNDAMENTALS OF BEER AND HOP CHEMISTRY 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: FUNDAMENTALS OF BEER AND HOP CHEMISTRY<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="main-festival-beer-list-006.htm">Previous Page View</a> | <a href="fundamentals-beer-and-hop-chemistry-002.htm">Next Page View</a><p>Search Completed. <BR> Publication Name: FUNDAMENTALS OF BEER AND HOP CHEMISTRY<BR> Original File Name Searched: 2152.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="" >DIVULGAC&#807;A&#771;O<br/><br/>FUNDAMENTALS OF BEER AND HOP CHEMISTRY<br/><br/>Denis De Keukeleire<br/><br/>University of Gent - Faculty of Pharmaceutical Sciences - Laboratory of Pharmacognosy and Phytochemistry - Harelbekestraat 72 B-9000 - Gent - Belgium<br/><br/>Recebido em 8/12/98; aceito em 23/3/99<br/><br/>Beer brewing is an intricate process encompassing mixing and further elaboration of four essential raw materials, including barley malt, brewing water, hops and yeast. Particularly hops determine to a great extent typical beer qualities such as bitter taste, hoppy flavour, and foam stability. Conversely, hop-derived bitter acids account for an offending lightstruck flavour, which is formed on exposure of beer to light. These various processes are presented in detail, while due emphasis is placed on state-of-the-art hop technology, which provides brewers with efficient means to con- trol bitterness, foam, and light-stability thereby allowing for the production of beers with consis- tent quality.<br/><br/>Keywords: beer; brewing; hops; bitter taste; flavour.<br/><br/>INTRODUCTION<br/><br/>Beer is a fermented aqueous drink based on starch and flavoured by hops. This simple definition encompasses the four essential ingredients, which are necessarily used in the brewing of beer (Scheme 1). The body of the beer is provided by barley, more specifically barley malt, and, in general, a few hundreds of grams are used for one litre of beer. The malt may be partly substituted by starch-rich adjuncts, such as rice, corn or wheat. When a slurry of barley malt and brewing water (called &lsquo;mash&rsquo;) is heated at a temperature around 60&deg;C, the malt enzymes, mainly amylases but also proteases, degrade starch and proteins, leading to a mixture of sugars and peptides or amino acids. For that purpose, barley must be subjected, prior to mashing, to a controlled germination, during which these enzymes are formed in the barley grain. Such germinated barley is known as barley malt. The starch- to-sugar conversion is stopped by heating. Depending on the conditions (time, temperature), pale or amber-coloured or even dark malts are obtained, the colour being due to caramelization of sugars and to Maillard-type reactions. It is important to notice that the colour of beer is derived from the colour of the malt(s) used. Furthermore, it is obvious that coloured malts exhibited a distinct taste, which often is characteristic of particular dark beers.<br/><br/>Mashing of barley malt and starch-rich adjuncts with brewing water Degradation of starch and proteins by malt enzymes<br/><br/>Filtration -&raquo; WORT<br/><br/>Wort boiling - addition of whole hops<br/><br/>Filtration -&raquo; HOPPED WORT Fermentation<br/><br/>Yeast removal -&raquo; &ldquo;GREEN BEER&rdquo; or &ldquo;YOUNG BEER&rdquo; Maturation - Lagering<br/><br/>Filtration -&raquo; BEER Packaging<br/><br/>Scheme 1. Overview of the brewing process.<br/><br/>E-mail: Denis.DeKeukeleire@rug.ac.be<br/><br/>After filtration, the sugar solution, in brewers&rsquo; jargon called &lsquo;wort&rsquo;, is transferred to the brewing kettle, where it is boiled during at least one hour with the addition of hops (Humulus lupulus L.). The amount of hops needed is only a fraction of the substantial quantities of malt used in the brewery. Usually, a few grams of hops are sufficient as a quantitatively minor, but qualitatively major ingredient with crucial impact on well- defined beer features. Besides the formation of insoluble complexes with proteins and polypeptides, contributing to the colloidal stability of beer, hops sterilize the wort solution, which takes care of the bacteriological stability of beer. The most important asset of hops is the bitter taste conferred to, particularly, blond beers. Furthermore, hops are necessary for the stabilization of beer foam, while, on the other hand, the most precarious off-flavour in beer, called lightstruck flavour, involves degradation of hop-derived components (see below).<br/><br/>After cooling and removal of spent hops, the liquid, known as &lsquo;hopped wort&rsquo; is pumped to the fermentation vessels and yeast is added under aeration for growth. During the anaerobic phase yeast cells convert sugars to ethanol and carbon dioxide. Depending on the temperature during fermentation and the nature of yeast collection at the end of the fermentation period, beers are distinguished as being produced by &lsquo;bottom fermen- tation&rsquo; or &lsquo;top fermentation&rsquo;. Yeast strains, appropriate for bottom-fermented beers (Saccharomyces carlsbergensis), are active below 5&deg;C and they settle to the bottom of the fermentor after production of about 5% ethanol. Conversely, yeasts, typical for the production of top-fermented beers (Saccha- romyces cerevisiae), operate at ambient temperature and resist higher concentrations of ethanol, up to 12%. When the activity stops, the yeast cells collect to the top as a dense foam.<br/><br/>A typical fermentation takes about one week thereby delivering a so-called &lsquo;green beer&rsquo; or &lsquo;young beer&rsquo;, which is not drinkable, as a number of offending (bad taste and smell) compounds are formed during fermentation. Consequently, beers need a maturation or lagering period of several weeks at about 0&deg;C, during which the unwanted components are slowly decomposed. High concentrations of diacetyl and pentane-2,3-dione are particularly obnoxious for the quality of lager beers (&lsquo;pilsner-type&rsquo;) and scrutinous monitoring is required. Only after the content has decreased below critical values (ppb-ranges), beer can be packaged. For prolonged conservation beers may be pasteurized. Special beers often require a slow (several months) second fer- mentation, usually in oak kegs, to generate sour flavours.<br/><br/>108<br/><br/>QUI&#769;MICA NOVA, 23(1) (2000)<br/><br/></span></TD><TD valign='top'><b>PDF Image: FUNDAMENTALS OF BEER AND HOP CHEMISTRY</b><BR><BR><img src='../images/fundamentals-beer-and-hop-chemistry-001.jpg' alt=' Supercritical Fluid Extraction FUNDAMENTALS OF BEER AND HOP CHEMISTRY 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>