Headspace: Espresso's Invisible Enemy?

puck of espresso with pooled water lifestyle by clive coffee

It's critical to reassure new home baristas that making great espresso at home isn't as hard as some say it is. Does it take some practice and require tasting a lot of espresso? It sure does! We need to hone our palate just like we sharpen our knives. First and foremost, making coffee is fun and doesn't need to be overcomplicated. That said, even once you’ve nailed the big variables, like grind size and puck prep, there are still a few subtle, sneaky factors that can throw off your shot. One of the most overlooked? Headspace.

Headspace is the gap between the top of your puck and your espresso machine’s shower screen. It seems harmless, right? A few millimeters couldn’t ruin an otherwise perfect shot— except it 100% can. Let's talk headspace, what it means, and how to maximize your chance for a better tasting shot. 

Why Headspace Matters

upclose shot of an espresso puck with a dent from the dispersion screen in the center lifestyle by clive coffeeWhen you start your shot, your machine first has to fill that empty space above the puck with water before it can build pressure. The more headspace, the longer it takes for pressure to build, and even a 5-second delay can alter your extraction in undesirable ways.

Extra headspace can also cause:
  • Uneven pre-infusion can cause a pool of water to form and sit stagnant on top of the puck before pressure fully builds, and can soak the coffee puck unevenly.
  • Turbulence can occur when water has extra room to swirl; it disrupts the puck’s surface, making channeling much more likely. This often happens when you're underdosing (not measuring enough coffee) based on your portafilter basket size. For example, putting 10g of coffee in an 18g basket will yield some crazy channeling. Always check the size of your basket when deciding on your starting dose. 
  • Weird, uneven pucks are normally not a big deal, unless you get visual feedback that your extraction went sideways.

The Cure 

  • Match your dose to your basket: Most baskets list an intended dose on the side of the basket. Stick within 1-2g of that. There are exceptions depending on the coffee, however. 
  • Use a puck screen. A thicker one can fill excess space, diffuse water evenly, and keep the puck’s surface flat during extraction. Our LUCCA Puck Screen is 1.85 mm thick, making it perfect for even distribution. Puck screens also earn bonus points for keeping your grouphead clean. 
  • Avoid overdosing: Too much coffee can mash into the shower screen, damaging the puck and, as a result, your extraction. Overdosing also adds to coffee waste. Why run out of coffee when you don't have to? Time to revisit your dose and adjust your grinder accordingly. 

Final Thoughts

Hopefully, this topic wasn't too much of a head-scratcher. Dialing in headspace is quick and simple and can save you from frustrating channeling or inconsistent extractions. A few millimeters do make a difference.

Further Reading: