Good distribution means ensuring that the density of ground coffee is even throughout the шайбу, both across the width of the шайбу and from top to bottom. A distribution method needs to effectively address the whole bed of coffee, not just create a flat surface.
Many distribution methods are referred to as ‘grooming’, meaning they smooth out the top layer of the coffee. These methods, such as Stockfleths, NSEW, and similar manoeuvres, typically involve using a finger or a special tool to spread out the coffee surface, but they don’t do much to distribute coffee lower in the шайбу. For this reason, and because of the extra time these methods can take, we at Barista Hustle don’t advocate grooming.
‘Distribution tools’ such as the OCD typically fall into this category as well: while they create a very smooth and flat appearance before tamping, they haven’t generally been shown to have a positive effect on extraction, suggesting that they are not effective in distributing coffee evenly throughout the coffee bed.
Our preference is for methods that use tapping to settle grounds into the portafilter. Tapping acts equally on the whole bed of coffee, and areas of the шайбу that are more dense will naturally resist the movement, allowing the less-dense areas to settle. This creates a more even density throughout the whole шайбу, even if the surface doesn’t always look as smooth due to remaining clumps.
Another method worth considering for making one coffee at a time, but too slow for a cafe environment, is stirring with a suitable tool — this is known as the Weiss distribution technique (WDT). By acting throughout the bed of coffee, this method can equalise density and also breaks up clumps.
A gif of the Weiss Distribution Technique using a jam funnel inserted into a filter basket to avoid spills
Finally, different techniques apply when you are using a single dosing grinder such as the EK43.