When any product is being designed the first that crosses the designers mind is the products safety. The portafilter gets put into the group head which is part of the machine itself. The group head is where the water flows out and drops into the portafilter when attached. The water is hot which means the group head is also very hot in turn making the portafilter hot and that is what creates the best tasting espresso. In order to keep all of the pieces hot they had to be made out of metal, but that could cause a problem for the barista handeling it. In order to prevent hands being burned a rubber piece was added to the handle. Not only does this protect the barista from burning his or her hands, but it also gives the handle a better grip. Some portafilter handles are shapped with a thicker piece of rubber at the end to be sure that it would not slip out of the barista's hand and some, like the one I use everyday at work, are shapped with ridges to allow the fingers to sit inside the handle better. This idea of differnt handle ends also comes into the second area of research which is comfort. The rubber ends are soft and are easy to hold, but also gives balance to the whole portafilter. Also the metal grips on the sides allow the portafilter to be locked in place when placed into the group head and is also compatable with some automatic grinders. Inside the portafilter is a little metal filter which looks like a disk with little holes poked through it. This little filter allows the espresso to seep through while the coffee grounds stay inside and away from your beverage. Now, the fifth and final area of research, and one that seperates each variation of products, is the aesthetics of the product. The portafilter is a product worth looking at and anilizing because it does so much for our huge generation of coffee lovers and most of them do not know just how wonderful the portafilter is. The rounded shape allows the ease of taking the portafilter in and out of the group head so the designers must have used that main focal point throughout the entire design. The handle and rubber pieces are all rounded and smooth to complement the main piece of the whole design. The way that the handle is shapped to fit your hand makes the barista want to hold it and constantly touch it which is good if the barista is making drinks all day. These differnt variations of the portafilter are only to modify the comfort and ease of using it on a daily basis.
Image Links: http://www.jimseven.com/2007/01/03/want-a-teflon-portafilter/, http://www.partsguru.com/GaggiaAchilleLevermodel.html
some links to buy espresso machines: http://www.peets.com/shop/essentials_espresso.asp?cm_re=essentials-_-feature1-_-Image, http://www.starbucksstore.com/products/shprodli.asp?DeptNo=8100&ClassNo=0036&SubClassNo=0950&CCAID=SBPTPAHP1SHEQ&Redir=/products/shprodli.asp?DeptNo=8100&ClassNo=0036&SubClassNo=0950