Thought I’d post this comment I made on Jimseven.com as it may be of iterest here too please feel free to comment.
Comment went as follows:
Hi James hope all is well and you are enjoying the rain.
Something that has been getting under my skin at the moment is trying to design a device for getting a consistently square manual tamp for relative newbies (I hate that term).It randomly popped into my head the other day whilst doing something completely different. I have some thoughts for you on the subject.
The current problem that any establishment will have is their very slightly different tamping style each barista will use. Some will roll the tamper in the group and compress one side slightly more unbeknown to them and others may roll the other way. This will inevitably create inconsistencies in the drink production.
This is a little inspired by the spaziale group which has a smaller radius and deeper basket. With a longer group and also a thicker headed tamper, say 3cm rather that 1cm, there would be less margin for error. A similar theory to that of a shot gun versus a sawn off shot gun. The normal shot gun with the longer barrel will fire straighter and more accurately whereas the sawn off shot gun will spray everything within a shot radius.
So, longer groups and thicker, correctly measured tamper heads.
I dare say this may involve some manipulation of the espresso machine but that’s always fun.