ABOUT PULLMAN CHISEL DISTRIBUTION TOOL
Any tool that pushes coffee in a downward motion is tamping.
To help increase the goal and chances of even puck density, there needs to be a happy compromise of enough equal downward motion (tamping) and horizontal movement (re-distribution) leaving still enough movement of compression when tamping. Here’s what will happen if you do-not set the Chisel correctly:
Not enough downward and horizontal movement (Chisel base depth set too shallow)
Increased air pockets due to coffee being separated by ‘pulling’ grinds during movement
Channelling not only through uneven sides, but also chance of channelling through the centre of the coffee puck due to uneven density formed by these airpockets (even after tamping)
Too much downward and horizontal movement (Chisel base set too deep)
After using, the tool will create too much downward motion and not enough sideways/horizontal movement resulting in uneven coffee puck density
Performing tamp action after this step will unseat or potentially crack the coffee puck leading to increased chances of channelling but also uneven water path/flow during extraction
Learning to set the depth of the Chisel base to use this tool to its best capabilities is by far the most important aspect of this tool.
The ‘happy’ place, meaning the correct depth setting, is a mixture of just enough downward/sideways re-distribution but also allowing some compression movement during the tamping stage.
Again, after performing the re-distribution with the Chisel, if when tamping there is not much compression or downward movement, the Chisel is set too deep and conversely, if there is too much compression or downward movement when tamping, the Chisel is not set deep enough.
We have found that there is a ‘happy’ place with most doses (irrespective of its roast level, though this must be taken into account with switching between roasts) to be around a 2mm of tamping compression or downward movement.
This helps achieve a better chance of even distribution using the Chisel, but still allows the tamping action to properly perform the task that its meant to – compressing the air pockets out of an evenly distributed coffee bed.
The biggest thing that many users discount is the way in which the coffee is being delivered into the basket. (Initial distribution)
If your grinder is delivering the grind into one corner of the basket, the density in that area will increase and adversely the density in the other areas of the basket will decrease.
Attention must be paid to the way the coffee falls into the basket and must be cared for and coaxed into an even delivery where possible, no matter if a re-distribution tool is being used or not.