Editing Beer (section)

===Draught ===

{{Main|Draught beer|Cask ale}}

[[File:Cask Ales.jpg|thumb|A selection of [[cask beer]]s]]

Draught (also spelled "draft") beer from a pressurised [[keg]] using a lever-style dispenser and a spout is the most common method of dispensing in bars around the world. A metal keg is pressurised with [[carbon dioxide]] (CO<sub>2</sub>) gas which drives the beer to the dispensing [[beer tap|tap]] or faucet. Some beers may be served with a nitrogen/carbon dioxide mixture. [[Nitrogen]] produces fine bubbles, resulting in a dense [[Beer head|head]] and a creamy [[mouthfeel]].<ref>{{cite book |title=Draft Beer Quality Manual |url=https://cdn.brewersassociation.org/wp-content/uploads/2019/03/13094643/Draught-Beer-Quality-Manual-2019.pdf |publisher=Brewers Publications |access-date=22 November 2024 |location=Boulder, Colorado |pages=3–4 |chapter=Draught Equipment and System Configurations |date=2019}}</ref> In the 1980s, Guinness introduced the [[Widget (beer)|beer widget]], a nitrogen-pressurised ball inside a can which creates a moderately dense, tight head. This approximates the effect of serving from a keg, at least for a British-style beer which does not have a specially large head.<ref>{{cite web |url=http://recipes.howstuffworks.com/question446.htm |title=How does the widget in a beer can work? |publisher=[[HowStuffWorks]] |access-date=5 November 2007 |archive-url=https://web.archive.org/web/20071102214918/http://recipes.howstuffworks.com/question446.htm |archive-date=2 November 2007 |url-status=live |date=16 August 2000}}</ref> 

Cask-conditioned ales (or cask ales) are unfiltered and [[Pasteurization|unpasteurised]] beers. These beers are termed "[[real ale]]" by the [[Campaign for Real Ale|CAMRA]] organisation. When a cask arrives in a pub, it is placed horizontally on a "[[stillage]]" frame, designed to hold it steady and at the right angle, and then allowed to cool to cellar temperature (typically between {{convert|11|–|13|C|F|disp=or}}),<ref>{{cite web |url=http://www.cask-marque.co.uk/beer-information/beer-temperature?highlight=YToxOntpOjA7czoxMToidGVtcGVyYXR1cmUiO30=|title=Beer Temperature |publisher=cask-marque.co.uk |access-date=21 June 2012 |url-status=dead |archive-url=https://web.archive.org/web/20121027200750/http://www.cask-marque.co.uk/beer-information/beer-temperature?highlight=YToxOntpOjA7czoxMToidGVtcGVyYXR1cmUiO30=|archive-date=27 October 2012 |df=dmy-all |date=7 July 2014 }}</ref> before being tapped and vented—a tap is driven through a rubber bung at the bottom of one end, and a hard [[spile]] is used to open a hole in the uppermost side of the cask. The act of stillaging and then venting a beer in this manner typically disturbs all the sediment, so it must be left for a suitable period of hours to days to "drop" (clear) again, as well as to fully [[Brewing#Conditioning|condition the beer]]. At this point the beer is ready to sell, either being pulled through a beer line with a hand pump, or simply being "gravity-fed" directly into the glass.<ref>{{cite book |title=Draft Beer Quality Manual |url=https://cdn.brewersassociation.org/wp-content/uploads/2019/03/13094643/Draught-Beer-Quality-Manual-2019.pdf |publisher=Brewers Publications |access-date=22 November 2024 |location=Boulder, Colorado |pages=95 to 97 |chapter=Appendix D: Notes on Serving Cask Ale |date=2019}}</ref>

Draught beer's environmental impact can be 68% lower than bottled beer due to packaging differences.<ref>{{cite web |title=Draught Beats Bottled in Life Cycle Analysis |url=http://www.treehugger.com/clean-technology/draught-beer-beats-bottled-in-life-cycle-assessment.html#ch01 |publisher=treehugger.com |access-date=15 January 2008}}</ref><ref>{{Cite journal |title=LCA of an Italian lager |journal=The International Journal of Life Cycle Assessment |volume=13 |issue=2 |pages=133–139 |doi=10.1065/lca2007.02.306 |year=2007 |last1=Cordella |first1=Mauro |last2=Tugnoli |first2=Alessandro |last3=Spadoni |first3=Gigliola |last4=Santarelli |first4=Francesco |last5=Zangrando |first5=Tullio |s2cid=111273627 }}</ref> A life cycle study of one beer brand, including grain production, brewing, bottling, distribution and waste management, shows that the CO<sub>2</sub> emissions from a 6-pack of micro-brew beer is about 3 kilograms (6.6 pounds).<ref name="newbelgium">{{cite web |title=Carbon Footprint of Fat Tire Amber Ale |url=http://www.newbelgium.com/files/shared/the-carbon-footprint-of-fat-tire-amber-ale-2008-public-dist-rfs_0.pdf |publisher=newbelgium.com |access-date=15 January 2008 |url-status=dead |archive-url=https://web.archive.org/web/20090224214330/http://www.newbelgium.com/files/shared/the-carbon-footprint-of-fat-tire-amber-ale-2008-public-dist-rfs_0.pdf |archive-date=24 February 2009 |df=dmy-all }}</ref> The loss of natural habitat potential from the 6-pack of micro-brew beer is estimated to be 2.5 square metres (26 square feet).<ref>{{cite web |title=Ecological effects of beer |url=http://ecofx.org/wiki/index.php?title=Beer |publisher=ecofx.org |access-date=15 January 2008 |archive-date=11 May 2011 |archive-url=https://web.archive.org/web/20110511150428/http://ecofx.org/wiki/index.php?title=Beer |url-status=dead }}</ref> Downstream emissions from distribution, retail, storage and disposal of waste can be over 45% of a bottled micro-brew beer's CO<sub>2</sub> emissions.<ref name="newbelgium" /> Where legal, the use of a refillable jug, reusable bottle or other reusable containers to transport draught beer from a store or a bar, rather than buying pre-bottled beer, can reduce the environmental impact of beer consumption.<ref>{{cite web |title=When Passions Collide … |url=http://terrapass.com/society/when-passions-c-1/ |publisher=terrapass.com |access-date=15 January 2008 |url-status=dead |archive-url=https://web.archive.org/web/20121111200646/http://www.terrapass.com/society/when-passions-c-1/ |archive-date=11 November 2012|df=dmy-all}}</ref>