Barista Basics 101: How To Prep A Puck and Dial In a Shot

You can source the best coffee beans, invest in the latest espresso machine, and still pull a sour, thin, or bitter shot of espresso. 

Delicious espresso shots aren’t magic or luck. They’re the result of thoroughly understanding how brewing variables interact to create a consistently delicious cup of coffee.

Once you understand the fundamentals of dialing in espresso, you’ll be able to brew balanced, sweet, and consistent espresso shots with ease.

Learning to dial in espresso may seem complicated on the surface, but we’re here to show you that it’s not! Here, you’ll learn:

• Why understanding extraction is essential for brewing espresso

• How to correctly prepare an espresso puck

• Tips and tricks for dialing in an espresso recipe

And it all begins with diving into espresso extraction.

Understanding Extraction: The Foundations of Brewing Espresso

If you’re new to the coffee industry, you might have heard the term “extraction.” 

Extraction refers to the process of “extracting” or “pulling” soluble natural compounds (acids, sugars, oils, and more) from the coffee grounds using hot water. 

However, these natural compounds are extracted at different rates and elicit varying flavors into the end cup.

• Acids, Sugars, & Caffeine: As they are the easiest to dissolve, acids and caffeine are extracted first. When tasted alone, these result in thin but bright or sharp flavors. Caffeine can also contribute to the perceived bitterness in a cup.

• Lipids & Fats: Next up, fats and lipids contribute to the perceived mouthfeel or “heaviness” of the cup.

• Melanoidins & Carbohydrates: Lastly, these natural elements (essentially, plant matter) yield an astringency or earthy note to the flavor profile. These compounds are more noticeable at higher TDS (total dissolved solids) levels, depending on the coffee and brew method used.

Coffee beans are only 30% water soluble—but not all of that 30% tastes good! Coffee professionals aim to extract 18-22% of a coffee’s natural compounds into the drink for a desirable flavor profile. 

This means it is possible to under or over-extract a coffee.

Under-extraction refers to when not enough of the natural compounds are extracted into the beverage. The resulting cup tends to be sour and unpleasant. Over-extraction refers to when we extract too much of the natural compounds, incorporating those bitter and undesirable plant fibers into the cup. 

To achieve a balance of flavors, we must manipulate brewing variables, including:

• Dose: How much coffee is used in a espresso recipe

• Yield: The resulting amount of liquid

• Grind Size: How fine or coarse the espresso grind size is

• Time: How long it takes to brew

Understanding how grind size, dose, yield, and time interact is the key to dialing in an espresso shot. Once you know how to adjust them systematically, consistency becomes predictable instead of frustrating.

How to Properly Prepare an Espresso Puck

Dialing in espresso begins with proper puck preparation. Without a well-prepped espresso puck, no amount of calibration will save your shot!

First and foremost: make sure you are using the correct basket size for your portafilter and recipe.

Portafilter baskets come in varying sizes, and using the wrong size basket for your recipe can result in all sorts of brewing mishaps, including channeling and pressure issues. For most espresso recipes at home and in the cafe, an 18-22 gram basket is a great option. 

Follow these steps to prepare your espresso puck:

1. Clean the Portafilter

Unlock the portafilter from the grouphead and wipe it clean with a dry microfiber cloth. This ensures that no residue or remnants from the previous shot remain in the basket. 

2. Grind the Coffee

Grind the coffee into the portafilter basket. Look for signs of clumping, as these hard, dense clumps of coffee grounds can cause water flow issues—also known as channeling—when brewing espresso.

3. Distribute and Level the Grounds

Even distribution of coffee grounds within the portafilter is a key part of espresso extraction. If the espresso grounds look clumped together or piled up on one side, this uneven distribution of grounds can cause channeling when brewing.

Channeling refers to uneven water flow through the espresso puck during the brewing process. This can cause issues with extraction, with some sections of the coffee grounds under-extracting and others over-extracting.

Fortunately, clumping and channeling can be reduced by evenly distributing and leveling the grounds. There are multiple ways to do so, including:

• Gently tapping the portafilter with your free hand to level out the grounds

• The Stockfleth method

• The Weiss Distribution Technique, which uses a small thin object or tool to break up clumps within the portafilter

4. Tamping

Espresso is brewed under pressure. To create that pressure and resistance within the portafilter and aid with an even extraction, you need to compress your espresso grounds together using a tamper and proper form.

Follow these steps to tamp your espresso puck correctly:

1. Place the portafilter on a flat, even surface

2. Hold the tamper like you would a doorknob

3. Using a straight wrist position with your wrist and elbow aligned over the portafilter, place the tamper gently and evenly into the portafilter

4. Apply steady downward pressure

Need a visual demonstration? Check out this clip!

If you’re working in a busy café, installing an automatic tamping tool such as a PuqPress can save valuable time (and achy barista joints from constant tamping.)

A Repeatable Method for Dialing In Espresso

Now that your puck is prepped, you’re ready to dial in your espresso recipe.

Traditionally, espresso uses a 1:2 coffee:water brewing ratio with a brewing time of between 20-30 seconds. While this isn’t a concrete rule, it’s a good recipe to start with as you learn the nuances of brewing espresso.

We’ve already reviewed the variables we need to manipulate (dose, yield, grind size, and time) to achieve these parameters, so let’s explore how to do exactly that.

Step 1: Set Your Dose and Yield

Start by determining the dose and yield of your recipe. 

Baristas and home brewers alike often make the common mistake of trying to adjust too many variables at once. Instead, deciding the desired dose and yield and sticking to it will make dialing in much more manageable!

We recommend starting with a dose of 18-20 grams of grounds and a yield of 36-40 grams of brewed espresso.

Step 2: Adjust the Grind

When brewing espresso, you need a fine grind size similar to the consistency of powdered sugar.

But remember: when hot water comes in contact with coffee particles, extraction happens! 

This means the espresso grind size is crucial in controlling how long the water and grounds are in contact with one another and therefore, how much extraction is possible. We can adjust the grind size finer or coarser to reach our desired brewing time of 20-30 seconds.

If you notice the shot brews too fast, this means it’s likely underextracted. Grind finer to remedy this.

If you notice the shot brews too slow, your espresso can be overextracted. Grind coarser to speed up the brew time.

Top tip: when changing your grind size, remember to clear any retained grounds from your grinder before the next shot!

Step 3: Taste Everything

While espresso recipes and grind size parameters provide baristas, coffee shop owners, and home coffee enthusiasts with the necessary guidelines, they’re not an “end all, be all” rule!

At the end of the day, it all comes down to how the espresso tastes. If a shot brews a little over 30 seconds or yields two more grams than desired, but still tastes incredible, you’ve dialed in an excellent shot of espresso!

Tasting your espresso shots will also help you dial in your recipe faster. 

If the shot tastes bitter…

• This is most likely caused by over-extraction 

• Grind coarser to reduce your brew time

• Reduce your brew ratio (if you extracted 40g of beverage, for example, try 36g)

If the shot tastes sour:

• This is most likely an under-extracted shot

• Grind finer to extend your brew time

• Increase your brew ratio (if you extracted 40g for example, try 44g) 

If the espresso is watery:

• Grind finer

• Decrease your brew ratio

• Check for uneven tamping

• Check for signs of channeling (pinholes in your coffee puck after extraction)

If the espresso is too heavy or thick:

• Grind coarser

• Double-check your dose

Step 4: Repeat!

No barista magically wakes up one day knowing how to perfectly dial in an espresso recipe. It takes time, experimentation, and repetition to refine your espresso brewing skills. 

At times, it may seem tough to dial in a delicious espresso shot, but don’t give up! The more you practice, the easier it’ll be.

Written by Anne Mercer