Have you heard about the Weiss distribution technique (WDT)?
The Weiss distribution technique sounds like something you might need to use when crop sowing or sorting out your finances. You could also be forgiven for thinking that WDT is a form of stroke or thrombosis.
Would you be surprised to hear that WDT is a process that was developed to improve coffee extraction not agriculture?
If you are looking to craft exceptional expresso, you might need to explore the benefits of WDT. Happily, it is a simple, pain-free process that doesn’t involve distributing anything other than coffee grounds.
What is WDT?
The Weiss Distribution Technique is named for John Weiss, who developed the process in 2005. He had been searching for a way to compensate for the poor results delivered by some coffee grinders. Grinds with excessive clumps were preventing Weiss from crafting the finest espresso.
WDT involves using a fine needle, or something similar, to stir coffee when it is sitting in the portafilter. A funnel placed above the portafilter helps prevent spills. The stirring action is effective in breaking up any clumps, and it evens out the density of the coffee. WDT reduces channelling and therefore produces higher and more even extraction.
At this point, you may be wondering what channelling is so allow us to explain. Water always takes the path of least resistance, even when water is passing through coffee grounds. If there are areas where coffee grounds are less tightly packed, water will run through those areas and so won’t pass through some portions of the coffee in a portafilter. This is why clumpy grounds lead to uneven extraction.
There’s no doubt that the latest commercial grinders deliver superior results, and you might think that they have rendered WDT redundant. However, many domestic grinders still produce clumps and coffee enthusiasts who have experimented with WDT feel that they achieve better tasting espresso, regardless of the consistency of the grind.
How do you practice WDT?
The most important aspect of WDT is choosing the right tool. Testing by baristas has shown that your needle or needles should be no more than 1mm in diameter. This would rule out a few potential options including toothpicks, some darning needles and knitting needles.
You should stir coffee grounds carefully and evenly rather than aggressively. There has been considerable debate regarding whether it is best to stir right to the bottom of the puck (deep WDT) or to stir only at the surface (puck raking).
Tests suggest that it is better to stir to the bottom of the grounds. This seems to ensure that there is less variation in the resistance of the coffee in the portafilter. Water will then flow uniformly, creating consistent flavour while minimising the chances of over-extracted or under-extracted areas in the puck.
You should stir for only a minute or so as using WDT for too long could result in overly degassed coffee. Degassing is the process of releasing carbon dioxide, and it can have a significant impact on both the taste of coffee and crema.
Can you make your own WDT tool?
Yes! Many coffee enthusiasts have created their own tools. These are often made by setting acupuncture needles into a wooden or plastic base. You could also consider using paperclips and setting your needles or clips into cork.
You may need to experiment with your tool to discover the perfect number of needles and how far apart they should be spaced. It is also worth noting that coffees vary greatly and so each will react differently to your stirring technique and tool.
It is possible to buy suitable tools if DIY isn’t your thing. You should be able to source a tool that works well for you.
What happens after the WDT process?
After stirring your grounds, you can proceed with tamping. You should notice more resistance than usual when you tamp. You may also observe a more even flow out of the bottom of the filter. If you use WDT you will benefit from delicious and consistent espresso.
Should professional baristas use WDT?
Baristas can be challenged for time during busy services and so even 30 seconds spent on WDT for each drink could prove problematic. Time is money and so for many businesses taking such care over espresso wouldn’t be practical.
But in small independent coffee shops, it could be worth using WDT to create extra-special brews.
WDT could improve anyone's espresso pours. Those who could benefit most would be home brewers or baristas whose grinders deliver clumps or uneven distribution. Also baristas who have yet to develop the skill to achieve consistent espresso extractions.
Some brewers will clearly benefit more than others from this technique. Stirring the grounds only affects dose and distribution and will not cure problems associated with stale beans or incorrect brew temperature, and so on.
Why should you explore WDT?
If you enjoy brewing coffee at home, why wouldn’t you try a technique that could improve your espresso? You might find that you can lend a whole new dimension to your drinks. Of course, you could discover that WDT isn’t enhancing your coffee sufficiently to impacts your enjoyment of your favourite beverage. In that case, it wouldn’t be worth spending the time to stir your grounds.
One thing’s for sure, you would be unlikely to make your coffee worse when using the technique.
Could WDT give you an epiphany or will it leave you underwhelmed? There’s only on way to find out!