Originally Posted by scottishslayer link=1208261828/0#0 date=1208261828
Do you really mean that or do you mean 60ml in 25 secs (it is a double basket)
If you are extracting a ristretto then 30ml in 25 secs would be OK - assuming you are using about 19 grams of grinds.
If you are trying to use the basket as a single (less coffee grinds) that will cause a problem as the tamper is a "perfect fit" only towards the top of the basket (where you would be if there were 18-19 grams in the basket). If you have say 14 grams (or less) the baskets taper a little and the tamper may fit too tightly at that depth.....
A convex tamper is also more forgiving of technique with an poorly fitted tamper (IMHO) but there should be very little difference, if any, between a flat and a convex base on a fitted tamper......
Also one tamp, and one tamp only.... and if you wish to polish the surface - use the wieght of the tamper only or very, very light pressure. Dont rotate it with anything like normal tamping force applied.
Hope that helps,