WHAT IS A WDT?
What is WDT tool? How does it help make the perfect cup of coffee?
The Weiss Distribution Technique (WDT) is a distribution method used during espresso making. Using a fine needle or similar tool, the barista stirs the coffee while it sits in the portafilter.
The stirring action breaks up any clumps, and evens out the density of coffee within the puck. The result is reduced channelling, and higher, more even extractions.
The technique was used as a way to compensate for poor quality grinders, especially smaller home grinders, that produced excessive clumping, especially when trying to create a fine grind. The WDT became well-known among home baristas, and has been written about extensively in the years since. Commercial and ‘prosumer’ grinders generally include features designed to break up large clumps and distribute the coffee more evenly into the portafilter basket, but recent studies suggest this is still not enough to create the very best espresso drink.
Detailed analysis of espresso techniques made possible by pressure or flow-profiling machines like the ‘Crem One LFPP’ and The ‘Decent’ machines have brought the WDT back into the limelight. By measuring pressure and flow inside the puck, we can see which techniques produce a more stable puck, and which are more prone to cause micro-channelling. By this measure, the WDT seems to show that it does make a significant difference when used.
Types of WDT
There are many types of WDT. Some WDT range from just a few pounds whilst others can cost several hundred! (Such as the Duomo Eight).
Duomo The Eight
What is important?
We have found needle size plays a huge role. Needles 0.4mm (or thinner) are advisable with any WDT that you make or buy.
Many people get good results making their own WDT. Although aesthetically they will not enhance your coffee area, they can be effective if made carefully. Key features of a good WDT are needles evenly spaced out and that reach the bottom of your coffee basket.
 Spinning WDT |  Homemade |
 Typical WDT |  Needles too wide for many |
Leveller: We have found the leveller type of tool distributes the top layer but does not distribute the lower part of the puck.
Contact us for more information and we will do our best to help you make the best choice for you.