Breakthroughs in espresso brewing don’t always happen at the surface. One of the newer trends gaining popularity is the blooming espresso profile, which is now recognised for its ability to improve coffee uniformity and extraction.
Originally derived from pour-over brewing, where blooming refers to the initial wetting of coffee grounds before extraction, this method is now being adapted to espresso. But is blooming worth the hype? Let’s explore how these profiles work, how they can improve extraction, and what experiments reveal about their effectiveness.
What is a Blooming Espresso Profile?
A blooming espresso profile is quite simple. It introduces a pause between the pre-infusion phase and full extraction, which allows the coffee puck to be fully saturated before the main extraction process begins.
During this pause, the coffee grounds expand and release gases (like in pour-over blooming), helping ensure even wetting of the coffee puck and preventing channelling. As a result, more coffee is extracted, and the overall flavour improves.
Timer Strategy for Blooming
- Pre-infusion: Water drips slowly, lightly moistening the grounds and initiating extraction.
- Pause: The clock stops, allowing the coffee to bloom and become fully saturated with water.
- Restart: Water flow and pressure resume, extracting the espresso.
Why Bloom in Espresso?
Blooming can lead to more balanced extraction by allowing the coffee puck to soak up water completely. Early water application can create internal channels in the coffee puck without blooming, leading to uneven extraction. This can result in some areas being over-extracted (bitter) while others are under-extracted (sour).
The blooming process also retains CO2 gas, locked into the coffee matrix, preventing channelling and improving the espresso’s flavour.
Experiment: Variable Designs with the Decent Espresso Machine
One notable experiment by Robert McKeon Aloe explored the use of blooming profiles on the Decent Espresso Machine. McKeon Aloe tested extraction yields and flavour profiles using coffee roasted three months prior and different blooming techniques.
Key Findings:
- Traditional Blooming Profile: A pre-infusion pause followed by extraction.
- Ramping Technique: During pre-infusion, the flow rate increased, leading to better extraction than traditional pre-infusion methods.
The experiment revealed that ramping up the flow rate during pre-infusion resulted in higher yields and a smoother shot. Adjusting the blooming stage brought about notable improvements in espresso quality.
Blooming Profiles Fine-Tuning: What Works?
Blooming profiles are flexible and can be customised for better performance. Here are some tips to enhance your espresso:
Ramp-Up Flow Rate During Pre-Infusion
Instead of maintaining fixed pressure, try ramping the flow rate to a target pressure of 4 bars. This ensures smooth saturation of the coffee puck, reducing the chances of channelling.
Dwell Time and Flow Rate
Adjust both the dwell time and the flow rate during the blooming pause. For example, McKeon Aloe found that a flow rate of 0.1 mL/s during the pause led to better saturation than a faster flow of 0.5 mL/s.
Extended Pre-Infusion Ramps
Instead of a quick blooming phase, try extending the ramp before extraction. This builds pressure more slowly, allowing for a smoother extraction process. Although not always consistent, experimenting with different coffees can yield exciting results.
Blooming in Lever Espresso Machines
Blooming techniques can be applied organically in lever espresso machines, where users manually control water pressure and flow. Lever machines allow baristas to create a pre-infusion effect by opening the valve at low pressure and closing it before full-pressure extraction begins.
This technique helps saturate the coffee puck while stabilising the extraction, particularly with lighter roasts. After introducing blooming, many lever machine users report improved clarity and sweetness in their espresso shots.
The Blooming Espresso Debate: Does It Make a Difference?
Is blooming worth the effort? The debate continues, but many baristas and industry experts like Scott Rao have experimented with blooming in espresso, finding that it enhances extraction and flavour clarity.
While not everyone agrees, the consensus among those who’ve tried blooming profiles is that they create more balanced shots, likely due to improved puck saturation and a gradual pressure build-up during pre-infusion.
Conclusion: Should You Try a Blooming Profile?
If you’re looking to perfect your espresso, blooming profiles offer a promising avenue for experimentation. Whether using a manual lever machine, a high-end pump espresso machine, or something in between, blooming can help improve shot consistency and bring out more flavour complexity in your coffee.
To start, try adding a pause before infusion, waiting 20-30 seconds, then proceed with the extraction. Experiment with different shot times and flow rates, keeping in mind that blooming can vary depending on the coffee beans you use.
With time and practice, you may find that the blooming phase sweetens and balances your espresso shots, revealing even more depth of flavour. Happy brewing!
