Before I got a Knock tube, I used to bang my portafilter against the garbage bin. I nearly broke it, so I started just scraping out the coffee with a teaspoon. I did this for about a year and no time did I ever notice scratches on the portafilter basket because of the spoon scraping.
A great idea Scout came up with, is to simply remove the wire from around the inner casing of the portafilter. This allows you to put in and pull out the basket with ease, and is also handy for dosing and measuring, as well as cleaning.
If you are making your own Knock box, make sure the rod you will be knocking on has some rubber piping (or something similar) around it, to protect the portafilter and absorb some of the shock. Banging directly onto a steel or wooden rod for example, will seriously damage your portafilter.
You should never have to knock so hard that you break something. A few gentle taps will loosen the puck enough for it to fall out. One or two huge wallops will eventually only end in tears. Remember that the ROK and Presso portafilters are much smaller than commercial ones and made of lighter materials, so they won’t be as strong.
What methods do you use to Knock with your ROK?
If you do have a Knock tube or box, what would you do to improve it?
Let us know!