There are many variables to consider when pulling espresso shots, which include dose, yield, extraction time, and grind size. As well as these, we also need to remember that puck preparation techniques – including distribution and tamping – are equally important.

Essentially, good distribution and tamping techniques help you to achieve even extraction and allow you to get the best out of your coffee.

During his winning 2022 World Barista Championship (WBC) routine, we saw Australian competitor Anthony Douglas use several distribution and tamping tools before he pulled his espresso shots. One of his tools was specially designed to carry out a distribution method known as the Weiss Distribution Technique (WDT).

So what is this technique, and why did Anthony use it in his routine? Moreover, should more coffee shops be using these distribution and tamping methods, too? 

I spoke to Anthony to find out more information – read on to find out what he said.

You may also like our article on channelling and how it affects espresso extraction.

What is the Weiss Distribution Technique and why is it used?

Before we discuss the WDT, as well as other similar methods, we first need to understand why distribution is so important.

In order to pull high-quality espresso shots, coffee needs to be ground very fine to increase the surface area of the particles. This is because espresso is extracted over a very short period of time using high-pressure water – which means you have a smaller window to extract desirable flavours and aromas in comparison to filter brewing methods.

Furthermore, because the grind size for espresso is so fine, this can sometimes lead to clumping. This is when ground coffee sticks together, which can cause a number of problems during extraction, such as channelling.

In coffee shops around the world, there are a number of ways that baristas can distribute grounds in a portafilter before extracting the coffee as espresso. 

One of the most common methods is to simply “tap” the basket of the portafilter against your hand or the surface of the counter. You need to repeat this until all the clumps break down and the grounds are evenly distributed throughout the basket.

This distribution technique is by far the most efficient one – especially during busy periods – but it doesn’t always produce the best results. 

The WDT, meanwhile, requires you to use a fine needle or similar utensil to stir the coffee grounds in the portafilter basket. Most WDT tools have around five needles, which help to break down clumps and create an even density of ground coffee.

The WDT was developed by John Weiss in 2005 after he found that some home grinders caused coffee to clump particularly badly. Since then, many baristas and coffee enthusiasts have adopted the technique. 

You can also place a funnel over the portafilter basket when using the WDT to make sure you contain all the coffee grounds while you stir them – otherwise your dose could be too small.

In his 2022 WBC routine, Anthony used a WDT tool which isn’t currently commercially available. This device (developed by Barista Hustle) is mounted on top of the portafilter and lowered down so that its needles run through the entire depth of the basket. You then spin the handle of the tool to remove any clumps and evenly distribute the grounds.

Anthony, who is also the training manager at Axil Coffee Roasters, explains why he used this specific WDT tool.

“During my 2022 Australian Barista Championship routine, I used one of Barista Hustle’s manual WDT tools,” he says. “It produced great-tasting espresso, but Matt Perger [the founder of Barista Hustle] was sat in the audience.

“After the competition, Matt approached me and asked if I would like to try a new WDT tool that they were developing,” he adds. “I then used this WDT tool on stage at the 2022 WBC.”

How effective is the Weiss Distribution Technique?

Anthony believes that the WDT is the most effective distribution method for baristas to use.

“It’s the best distribution method that I have used because it’s the only technique that evenly distributes ground coffee from top to bottom, as well as side to side,” he explains. “In turn, I’ve experienced the best results with this method.”

So are there certain procedures you should follow when using the Weiss Distribution Technique to get the best results?

Firstly, we need to consider which type of tool you are using – particularly the size and length of the needles. Ideally, the needles need to be thin, but not too thin that they could break as a result of heavy use. Some professionals recommend using needles which are no wider than 1mm to ensure grounds are distributed evenly.

Moreover, all needles should be able to reach the bottom of the portafilter basket so that they can evenly distribute ground coffee throughout the entire basket. If the needles aren’t long enough, for example, only the surface of the puck will be distributed, which could lead to channelling or other issues.

Anthony explains that the needles of the WDT tool he used in the 2022 WBC were spaced in a way which meant they distributed the entire surface area of the basket in one spin. Ultimately, he says this helped him to extract a repeatable and consistent flavour profile, with blackberry as one of the most prominent tasting notes.

“They help to ‘fluff’ up the ground coffee more, which means that it’s easier to distribute the grounds,” he tells me. “This is because the more compact the grounds are [before tamping], the harder it is to distribute them.”

During his 2022 WBC routine, Anthony also spun his WDT tool for just under ten seconds, which he says helps to result in more even distribution, too.

However, when carrying out the WDT, it is possible to overstir the grounds or distribute too aggressively. Ultimately, you should always stir the grounds in a careful and controlled manner to achieve the best results.

What about tamping?

As well as distribution, it’s also important that we consider tamping techniques.

In simple terms, tamping is when you apply force to ground coffee in a portafilter basket, which makes the puck compact.

However, if you tamp unevenly distributed coffee, you can create an uneven puck. In turn, this can negatively affect your espresso extraction.

Knowing how much force to apply when you tamp is important, but you also need to factor in the shape of the tamper you are using. There is a wide variety of tampers available – including convex, flat, calibrated, and even automated tampers. 

In recent years, we have also seen the emergence of height-adjustable levelling tampers, such as the Nucleus Coffee Distribution tool which was designed by 2015 World Barista Champion Sasa Sestic. These types of tampers have angled slopes instead of a flat base, which helps to move ground coffee in a circular motion, thereby improving the evenness of the puck

No matter which type of tamper you use, one of the most important things is to ensure that your tamper fits snugly into the portafilter basket. Many coffee professionals recommend using a tamper that is around 0.3mm smaller in diameter than a portafilter basket. 

This is because if the tamper is too small, you won’t be able to evenly tamp the entire puck. Conversely, if the tamper is too big, you could risk getting the tamper stuck in the portafilter and disturbing the coffee puck.

In his winning WBC routine, Anthony used a two-step tamping process for all of his beverages – he first used a levelling tamper before using a Great Leveller spring-loaded tamper.

“The outer rim of the calibrated tamper I used in my routine is 58.5mm in diameter, so it sits on the edge of the portafilter basket,” Anthony says. “Because it’s spring loaded, it means you push down on the handle and the base of the tamper goes into the basket to compress the coffee grounds.

“It helps to maintain a level tamp, so there’s no way that you can tamp unevenly,” he adds.

Should we be using more Weiss Distribution Technique tools in coffee shops?

Anthony says he would like to see more baristas using the WDT in coffee shops.

“Baristas should know how to tamp properly in the first place, but using the WDT also helps to improve consistency,” he explains. 

Ultimately, if carried out correctly, using the WDT would allow baristas to achieve more even extraction, and therefore serve better-quality beverages.

“If you’re doing the WDT manually, it can be difficult to do it with every drink you make, so maybe it could be used for more expensive coffees,” he adds. “But if you use a WDT tool like the one I used at the 2022 WBC, it can be much quicker and easier.”

On a similar note, the increasing number of automated tampers in coffee shops means that tamping can also be a more efficient process, especially during busier periods. 

“In my experience, I get better results with manual tamping, but if I’m working behind a busy bar, an automatic tamper like the PUQpress would help to improve my workflow,” Anthony explains.

There are many important steps to consider when preparing high-quality espresso, including distribution and tamping. However, when you distribute and tamp your puck correctly, you can extract coffee more evenly and end up with better-tasting results.

And while tamping is a common practice in the vast majority of coffee shops, the WDT is certainly less popular. However, whether or not this method will be used more widely by baristas remains to be seen.

Enjoyed this? Then read our article on why it’s time to rethink coffee distribution.

Photo credits: World Coffee Events

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