Editing Espresso machine (section)

==Machine parts==
{{Refimprove section|date=January 2025}}
[[Image:grouphead.jpg|thumb|A grouphead from a domestic espresso machine]]

{{anchor|Grouphead}}A grouphead (or group head) is the receiver for the removable portafilter (or group handle). A typical consumer espresso machine normally has only one grouphead, while popular professional machines, such as those used at commercial coffee shops, can contain anywhere from one to seven. During the process of extracting a shot of espresso, hot water is forced through the grouphead under pressure. The grouphead contains many holes (the shower) that attempt to distribute the pressurised water evenly over the surface of the grinds in the portafilter basket and thereby achieve an even cross sectional flow.<ref>{{cite web
| url=http://community.wholelattelove.com/blogs/2513/the-e61-brew-group-demystifying-the-mystique
| title=The E61 Brew Group. Demystifying the Mystique.
| date=2005-01-24
| archive-url=https://web.archive.org/web/20150831132900/http://community.wholelattelove.com/blogs/2513/the-e61-brew-group-demystifying-the-mystique
| archive-date=2015-08-31
| url-status=dead
| work=wholelattelove.com}}</ref>

[[File:Portafilter and tamper.jpg|thumb|Portafilter of a home espresso machine with a tamper on it]]
{{anchor|Portafilter}}A portafilter (or group handle) attaches to the grouphead of semi-automatic and piston-driven espresso machines, and carries a tamped puck of coffee grounds within its basket.  It is usually made of brass for better heat retention, and is attached by a plastic or wooden handle. The portafilter forms a seal with the espresso machine's gasket, and directs high-pressure hot water through the coffee puck. After-market retailers also sell bottomless portafilters that minimize the espresso's contact with any metal. A bottomless portafilter is one tool [[barista]]s use to analyze the quality of the coffee grind and the evenness of the extraction and allows for a visual check of "channeling" or the condition in which water is able to pierce a hole in the espresso puck during the brew process leading to poor extraction. Often, baristas use [[knockbox]]es to store their spent espresso grounds after they have pulled a shot.