Gaggia Bottomless Portafilter Complete With 21g Basket

I've had my Gaggia Classic since 2009 and only ever used it with the supplied double portafilter, which I've always been happy with. However. having recently read about bottomless portafilters and their improved extraction of espresso and greater amount of crema, I decided to invest in one. Since it arrived I have used it several times, with varying degrees of success. However there seems to be a problem which occurrs shortly after starting the extraction process. The issue being that whilst most of the coffee being extracted goes into the cup, it also 'spirts' out of the edges of the filter basket, missing the cup completly and covering the surrounding area in coffee. As a result I've given up trying to use it and reverted to my original double portafilter. On the plus side the bottomless porterfilter is really well made and I'd have been very happy with it, if it hadn't been so messy to use.