Why is puck prep so important for pulling the perfect shot? 

I like to think of it like painting a room—it's all in the prep. Without proper preparation, you could experience channeling and a lower extraction yield, meaning you won’t get that rich flavour with a heavenly, oily crema floating on top that you so deserve. I’m going to dive into some practical tips and a bit of science to help you achieve that perfect shot.

The goal of each shot is consistency and the ability to change one variable at a time in your quest for espresso nirvana. Starting with the grinder, the grounds are dispensed into your portafilter. Because the grounds are so fine, clumping can occur. This can be due to the oil content in the beans, static electricity caused by the grinding process, or how the grounds are dispensed by your grinder (

Clumps are bad. They introduce inconsistencies in the particle size and spacing between the grounds, leading to an uneven extraction. When hot water is forced through, the smaller grounds will over-extract (

), while the larger grounds will under-extract compared to the average ground size. This inconsistency can also lead to a phenomenon called ‘channeling’.Because the spaces between the grounds are not uniform, water will take the path of least resistance, 

flowing mostly through one part of the portafilter

. This bypasses a lot of your precious grounds, leading to under-extraction and a watery shot. Finally, with both of these issues, you won’t maximize the amount of oily, delicious goodness going into your cup.How much ‘coffee juice’ you get from a shot is what coffee enthusiasts call ‘extraction yield’.

Now that we've laid out the pitfalls on your path to crema glory, let’s dive into some proven techniques to refine your puck prep and slay these clumpy beasts:

Let’s start with the easiest technique: 

. This is a fancy-sounding way of saying you tap the bottom or side of the portafilter to break up clumps and spread the pile of grounds into a flat, even surface ready for tamping.

The coffee world seems to love three-letter acronyms. 

. It involves lightly wetting the beans before grinding to reduce static electricity. The easiest way is to wet a spoon and stir the beans before grinding. Voila! RDT done.

You can probably guess what this is: a funnel you place on top of your portafilter before grinding to catch all the grinds and minimize any grounds spilling over if you get a little aggressive with vertical or horizontal tamping. It also lets you try some funky techniques, like moving the portafilter in a circular motion under the grinder to have the grinds fall more evenly into the filter basket.

Instead of using a funnel on top of the filter basket, why not have the grinds fall into a special cup (one sized to fit your filter basket)? To use a dosing cup, grind your beans into it, then use your favorite distribution technique, such as horizontal distribution, WDT, or shaking. Afterward, place the portafilter on top and flip it upside down to transfer the grounds into the filter basket.

, popularized in 2005 by John Weiss, has generated a lot of buzz. It involves a tool that looks like a tiny scalp massager for your grounds. The WDT tool consists of a handle with multiple fine needles protruding from the end. The goal is to stir the grounds, starting from the bottom of the basket and working your way up, to break up clumps and achieve a fluffy, uniform distribution. To dive deeper into the technique, watch this excellent 

https://introvertmakes.com/pages/in-depth-look-at-wdt-tools#:~:text=The%20Weiss%20Distribution%20Technique%20(or,hopefully%20result%20in%20better%20flavour

We’re a little biased when it comes to this technique,- but let's be real: shaking is best.When you shake, magic happens at a particle level. Unlike other techniques such as WDT, or manual distribution, which can cause the dreaded “Brazil nut effect,” (if you’re not sure what that is, 

 shaking will distribute grounds more uniformly.According to Dr. Al Shimmeri, a coffee roaster and researcher, shaking helps fines (tiny coffee particles) bind to larger grounds, 

 . This means fewer over-extracted, bitter notes and fewer under-extracted, sour notes. Translation: A more balanced espresso shot.The IRIS shaker functions as a dosing cup, funnel, distributor, and shaker, all in one package. It even discharges static electricity when you shake it, thanks to its aluminum construction.

There’s a particular technique we recommend to ensure the grounds are evenly distributed. Using figure-eight and swilling motions, as demonstrated in our video, we found will get you best results. And while other shakers require flipping to transfer the grounds or fiddling with a release, our IRIS uses a unique snap-release bottom, allowing the grounds to drop straight into the filter basket, ready for tamping.

Tamping is the final, must-do step on your puck prep journey. Once the grounds are homogenized (to the best of your ability), it’s time to apply pressure to the puck to uniformly pack and densify the grounds. If everything goes well, this will prevent channeling and give you that intense flavour you’ve been working toward. Without this final step,you’ll end up with watery coffee and wasted grounds. A pressure of about 25-30 lbs.should do the trick; anything more and you’re just straining yourself. As you lift the tamper, give it a little twist to “polish” the top, and voila, you’re ready to pull that shot. Tamp pressure is another variable to experiment with, depending on your grind size. 

This video delves deeper into tamp pressure

Puck prep is a journey, and there’s no shortage of techniques to explore.There are DIY methods like tapping your portafilter, making a funnel from a yogurt container, or sticking needles into a cork to try the WDT technique. These are all part of the fun and can be tried inexpensively. With shaking, you get clump-free, evenly distributed grounds in seconds—without the static, mess, or tedious stirring. And with ourIRIS shaker, you take it up a notch!It functions as a dosing cup, funnel, distributor, and shaker all in one, with the bonus of a static-free snap-release system that neatly drops your grounds into the filter basket—no flipping, no fiddling, no spills. 

At the end of the day, the best puck prep method is the one that works for you. That’s the beauty of coffee. But if you’re after better extraction, a cleaner workflow, and a more consistent shot, shaking is worth a try. Give it a go and let us know what worked for you in the comments below!

An intro to puck prep methods for the perfect Espresso shot

At the heart of every great espresso shot is consistency, and that’s where IRIS shines. Designed to evenly distribute coffee grounds, this innovative tool eliminates uneven clumping and ensures a smooth, balanced extraction. It’s perfect for anyone serious about making their best espresso yet — whether they’re beginners or seasoned baristas. Recently launched on Kickstarter, you would have to splurge and get the Special CNC’d version for it to land under your tree.
What Makes IRIS Special:

Precision Grounds Distribution: Achieve consistent flavour extraction with ease.

Anti-Static Coating: Keeps your workspace clean and hassle-free.

Unique Shutter Mechanism: A smooth, satisfying release of grounds every time.


Tamping is all about pressure, and this spring-loaded tamper guarantees consistency with every shot. The even density it provides is the perfect follow-up to IRIS’s evenly distributed grounds. Together, these tools ensure a balanced puck for maximum flavour extraction.


 IRIS sets up the ideal grounds, and this tamper locks them in place for flawless results.


3. Fellow Atmos Vacuum Canister ($30-$50)


Fresh coffee beans make all the difference, and this sleek vacuum canister keeps your beans fresher for longer. The Atmos air-tight container preserves the flavours and aromas of your coffee beans by slowing oxidation. IRIS works best with perfectly ground, fresh beans — making this canister a must-have companion.


 Use the Atmos to store your beans, grind fresh, and let IRIS take them to the next level.


Precision in measurement is crucial for a perfect espresso, and the Bookoo Coffee Scale delivers. With a fast response time and readability up to 0.1 g, it ensures you measure your coffee and water with utmost accuracy. Its sleek design and Bluetooth connectivity make it a favorite among even the most discerning enthusiasts.


Use the Bookoo Scale to measure your coffee dose accurately before using IRIS for even distribution, setting the foundation for a flawless shot.



Meet the world’s finest hand coffee grinder. The push-release top cap allows quick access to the bean hopper. The grind handle extends and retracts for double duty as a locking carabiner handle. The grinder knob threads to attach within the catch when not in use, and with the magnetic integration sits securely on the extended grind handle. Its 420 stainless steel conical burrs and dual bearings provide the most consistent grind size of any hand-grinder on the market.

 VSSL loves the outdoors, so does IRIS. Take both with you and brew perfect cups anywhere and everywhere.


Espresso-making is a combination of science, art, and the grounding ritual that kicks off another chance to create a great day. Having the right tools makes all the difference. Whatever you — or someone special on your list — does in their day, start it off with IRIS. We know that first pull is the foundation of a good morning, so let IRIS create the perfect foundation for any shot. These four accessories enhance and elevate what it does, so that together, they deliver café-quality espresso every time. Here’s to good mornings!


The ultimate Guide to Gift the Coffee Enthusiast On Your List 

At its core, shaking addresses the issue of 

—a major cause of inconsistent brews. Whether you’re pulling espresso shots or brewing pour-overs, evenly distributed grounds ensure uniform water flow, preventing channeling and unlocking the full potential of your coffee.

When fresh coffee grounds are poured straight into a brew basket or porta filter, grounds tend to clump together, and coffee particles are unevenly distributed. When coffee is brewed, water takes the path of least resistance, a phenomenon known as 

. This leads to over-extraction in some areas (bitter flavors) and under-extraction in others (sour or weak notes). The result? A muddled, unbalanced cup that doesn’t showcase your coffee’s best flavors.

Baristas, coffee lovers and coffee enthusiasts have come up with an array of techniques over time to extract the best possible flavours. The relatively new method of shaking grounds breaks up clumps and evenly distributes the coffee in a process called densification, creating a uniform bed that allows water to flow smoothly and extract flavors consistently. This is especially important in espresso preparation, where precision is key, but it also benefits manual brewing methods by enhancing saturation. Shaking essentially ensures that every ground contributes to your coffee’s final taste.

Opinions on shaking are varied but consistent in their support of even distribution. Some baristas prefer shaking for its simplicity, while others combine it with techniques like leveling or tapping. What’s universally agreed upon is the importance of avoiding channeling to ensure consistent extractions. We will continue to investigate and reasoning and why shaking does work the way it does. If you are also interested in this matter, we’ve collected some great resources of fellow coffee lovers to help you dive deeper into this topic:

Our current top 3  Videos on learning more about coffee prep:

Our friend and fellow coffee nerd Lance Hedrick has shared this video on various prepping methods. 

https://youtu.be/OyUaCuoqYWc?si=fywCFMmup0bqh7OH

This one draws a little different picture on shaking, we are still trying to find out how her results differ from those of others, but we liked the overall approach. 

https://www.baristahustle.com/shake-it-real-good/

To into Coffee Making, this great video from Sci Show dives straight into the science of it. 

https://www.youtube.com/watch?v=xUoFhcQBiZY

Shaking isn’t just a step—it’s a method that ensures your coffee reaches its full potential, over and over again. With our Iris coffee shaker, this process becomes effortless, fun and bringing you one step closer to consistently better tasting coffee. Try it for yourself.

What are your thoughts on shaking coffee grounds? We would love to hear from you. Share your experience in the comments!

Why We Shake: Some Science Behind Better Coffee

Today, we’re pulling back the curtain to share how a simple problem led to the creation of a tool that’s now changing how people brew coffee—and a brand dedicated to making coffee better for everyone.

The Problem: Inconsistent Coffee, Every Time

Like many coffee lovers, we were frustrated by inconsistent results in our daily brews. Even when we followed every step of the process, the coffee didn’t always taste the way we wanted. We searched for solutions but found the existing tools were either ineffective, overly complicated, or simply didn’t address the problem we faced.

It wasn’t just a personal frustration—it was a universal problem faced by coffee enthusiasts everywhere. And that’s when the idea struck: 

What if we created our own tool to fix this?

Determined to make a difference, we set out to design something simple, effective, and approachable. We weren’t just creating a product; we were launching a brand rooted in the belief that great coffee shouldn’t require guesswork or an advanced degree in barista techniques.

We started with big questions: How could we eliminate clumping? What would make the brewing process easier? And most importantly, how could we help people enjoy consistently great coffee every day?

From these questions, the first prototypes of Iris began to take shape. We tested and refined our designs, learning as we went. Every success revealed a new challenge—materials that didn’t work as intended, designs that felt awkward, or manufacturing methods that were too expensive for large-scale production.

The learning curve was steep. Bringing an idea to life isn’t just about having a great concept; it’s about navigating the realities of production, logistics, and economics. But every hurdle reinforced our commitment to the mission: to create tools that simplify coffee-making without compromising on quality.

Finally, after months of prototyping, testing, and refining, Iris was ready to meet the world. We launched our 

, sharing our journey and inviting coffee enthusiasts to join us in bringing Iris to life. It is great seeing our vision resonate with other people and get reaffirmed that all the hard work has been worth it.

Besides working tirelessly to make sure people learn about Iris, know this is just the beginning. At Repertoire Coffee, we never stop thinking about the next solution to make better coffee. We’re already hard at work on new tools that will continue to make coffee-making easier, cleaner, and more enjoyable. Stay tuned or sign up for our newsletter to find out what’s brewing behind the scenes.

Launching a product like Iris has been a journey filled with challenges and growth, but it’s also been a labor of love. Thank you for supporting us and being part of this adventure—we’re just getting started.

From Idea to Reality: The Journey of Creating IRIS

Whether you’re a seasoned barista or a coffee enthusiast brewing at home, you’ve probably encountered a frustrating issue: 

 This can happen when coffee grounds clump together or don’t distribute evenly in your portafilter or basket. These uneven clumps create channels where water flows too quickly, over-extracting some grounds and under-extracting others. The result? A cup that’s either too bitter, too sour, or just lacks that perfect balance we all crave.

 steps in. Shaking your coffee grounds before brewing ensures they’re evenly distributed, breaking up clumps and creating a uniform bed of coffee and densifies your grounds. This evenness and densification is critical for achieving a consistent extraction—where every ground contributes equally to the brew. Think of it as setting the stage for water to do its best work, delivering a rich, flavorful cup every time.

But why shake instead of stir or tap? Stirring can sometimes lead to uneven compaction, while tapping may not break up those stubborn clumps. Shaking, on the other hand, naturally distributes the grounds without over-compacting them, thanks to the gentle, even motion Iris is designed to provide.

When coffee grounds are evenly distributed, water flows through them at a steady rate, extracting the ideal flavors from every particle. This prevents the dreaded “channeling” effect that leads to weak or uneven brews. The result is a cleaner, more balanced taste—whether you’re brewing espresso, pour-over, or even using your trusty moka pot.

Iris isn’t just about better coffee; it’s about a smoother brewing experience. With its compact design, it fits seamlessly into your coffee-making routine without taking up extra space. And let’s not forget—it’s a mess-free solution that keeps your countertops clean while streamlining your prep. No more second-guessing your technique or dealing with inconsistent results.

We’re so excited for you to try Iris and see the difference it makes in your coffee journey. Stay tuned to our blog for more brewing tips, product updates, and the science of coffee—because at Repertoire Coffee, we believe better tools mean better coffee.

Introducing IRIS: The Coffee Shaker to shake up your coffee routine

Vancouver, BC – Vancouver-based Repertoire Coffee Products is thrilled to announce the launch of their first product, the IRIS Coffee Grounds Shaker, on November 13, 2024, at 12:00 PM PST. Founded by James Mallion, and co-founders Sebastian Mueller, Liam Levesque, and Ian Christie, the company focuses on modernizing classic coffee tools for the home and professional barista, ensuring that anyone can create perfectly balanced, flavorful brews. The IRIS Shaker promises to deliver a new level of precision and control to coffee and espresso enthusiasts, setting a new standard for coffee extraction consistency.

The IRIS Coffee Grounds Shaker stands out with features that address common pain points in coffee preparation, particularly around grounds distribution and consistent extraction results. IRIS utilizes anti-static materials and coatings that ensure a smooth grounds transfer, while its unique shutter mechanism provides a quick, even, and hassle-free release of shaken grounds. Designed for ease, elegance, and repeatable results, IRIS is crafted for both at-home coffee enthusiasts and seasoned baristas who value efficiency and quality.

“We designed IRIS to address the small frustrations we all experience when trying to brew a truly great cup of coffee,” said James Mallion, Founder of Repertoire Coffee Products. “From materials to mechanics, every detail has been carefully crafted to make the brewing process as seamless as possible, while enhancing flavor extraction for a remarkable experience and overall better tasting coffee.”

Key Features of the IRIS Coffee Grounds Shaker Include:

 IRIS’s specialized mechanism disperses grounds evenly, enhancing extraction for consistently great flavor.

 Minimize coffee residue and ensure a clean, seamless transfer of grounds.

 This intuitive feature enables a smooth and satisfying release of shaken, densified grounds, making coffee prep more enjoyable.

In celebration of the Kickstarter launch, backers will receive exclusive pricing on the IRIS shaker, with a special raw-finish edition available for early supporters, just in time for the holidays. The estimated delivery date for all Kickstarter orders is February 2025.

Founded in 2023 in Vancouver, BC, Repertoire Coffee Products seeks to reinvent classic coffee tools, delivering unmatched quality and user-friendly design. With a focus on craftsmanship and ease, Repertoire empowers coffee lovers to achieve café-quality results, no matter where they are.

For media inquiries, interviews, or review samples, please contact:

Join us in bringing IRIS to life! For more information and to back the project, visit [

https://www.kickstarter.com/projects/repertoire/iris-shake-up-your-espresso-routine?ref=51vhxs

] starting November 13, 2024, at 12:00 PM PST.