Also check out the Updated Technique page.
We grind directly into the top of the Sifdis. Approximately half of a gram of coffee falls thru at the beginning of grinding. We simply sweep it back into the top of the Sifdis after grinding.
Obviously, when something is spun in a circle, there is a dead spot in the middle with very little movement. To overcome this we created the conical screen. Because of the conical screen, there is some control over where the coffee grinds end up. Spin faster and the coffee falls more around the edge, spin slower and it falls more toward the middle.
It is essential to have a way to set the filter basket level so the coffee can fall straight down into the basket.
It may take a few tries to find the correct spinning speed and technique to distribute the coffee evenly across the basket. Personally, I prefer spinning full revolutions with one finger on the edge of the "gear", but stopping at a different spot around the clock each time. Keep in mind that once the grinds are sifted, there is a much fluffier bed of coffee. If there are mountains or valleys, they even out much easier with tamping.
It can be beneficial to turn the bottom of the Sifdis as the top is spun to achieve an even better distribution. It is not absolutely necessary, but helpful to achieve the "perfect" distribution. Once the technique is learned, finger-striking or any other type of grooming becomes unnecessary. It takes around 30 seconds for 18 grams of coffee to go thru the Sifdis.
We also believe that tapping the portafilter on the counter will "ruin" the distribution. Therefore, once distribution is complete, it is ready for tamping.
We have tried both flat and curved base tampers and feel that a curved base tamper produces a little better results. Of course this may vary depending on espresso machine.
Below is my previous technique at actual speed with no cuts.