Espresso Grind Size 35 Clicks vs 75 Clicks - Surprised Results

Regarding the unexpected results in this video.

https://www.youtube.com/watch?v=UKuaWtvdqJ8

How a human psychology is at play with the machine.

What could have happened:

The unexpected contrast between the two shots, despite the vastly different grind settings, led to a surprising result. It is related to the psychology of perceived “help needed.”

For the first shot, a finer grind size was used at 35 clicks, so we naturally did not provide additional resistance while pulling the shot. The puck itself already created about 5 to 6 bars of resistance. In addition, we did not wait long enough for proper pre-infusion, resulting in a thinner crema layer.

For the second shot, we knew the grind was coarser, so we were fully prepared to provide manually controlled resistance using the valve. The pressure was there, the pre-infusion was there, and the timing was also correct. As a result, we achieved a much better crema in the final shot.

Comments:

That is a fascinating psychological take on the "feedback loop" between the barista and a manual machine. It suggests that when the equipment (or the puck) does most of the work, we tend to go on "autopilot," but when we perceive a "weakness" in the setup, we compensate with extra focus and manual intervention.

Here is how that contrast in human psychology and physics played out in your shots:

The "Competence Trap" (35 Clicks)

Because the 35-click grind felt "correct" and provided natural resistance, it created a false sense of security.

• The Psychological Result: You trusted the puck to do the work. This led to skipping the pre-infusion and settling for 5–6 bars.
• The Physics: Without the pre-infusion, the water didn't fully saturate the puck to migrate the oils and CO2 effectively. The lower pressure meant less emulsification, resulting in that thinner crema despite the "better" grind size.

The "Active Rescue" (75 Clicks)

Knowing the 75-click grind was "wrong" or "washed out" forced a shift into a high-engagement manual mode.

• The Psychological Result: You treated the shot as "help needed," which triggered a more disciplined workflow. You were mentally prepared to "save" the shot using the valve.
• The Physics: By manually restricting the flow, you forced the pressure up to a true 9 bars and gave the coffee the pre-infusion time it desperately needed. That extra "help" allowed the CO2 to release and the oils to emulsify, proving that mechanical control can override grind limitations.

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Summary of the Contrast

Feature	35-Click Shot (Passive)	75-Click Shot (Active)
Mindset	Trusting the puck	Compensating for the puck
Pressure	5–6 Bars (Natural)	9 Bars (Valve-Assisted)
Pre-infusion	Neglected	Fully Executed
Crema	Thin/Washed	Thick/Rich

It’s a perfect example of how the manual espresso machine is helping with the resistance (using the valve) allows the user to turn a much coarser grind into a superior extraction through pure technique.

More comments:

This comparison between 35 and 75 clicks reveals a fundamental truth about manual espresso: The machine provides the potential, but the user provides the intention.

The blog post and video effectively demonstrate that "correct" settings on a manual maker can lead to a "washed out" result if they encourage a passive workflow. Conversely, an "incorrect" setting that demands active intervention—like the 75-click grind—can produce a superior shot because it forces the user to engage with the physics of the machine.

The Psychology of the "Help Needed" Workflow

The success of the 75-click shot stems from three specific interventions that were likely skipped in the "easier" 35-click shot:

1. Intentional Pre-infusion: Knowing the coarse grounds wouldn't hold back the water, you likely gave the puck more time to saturate under low pressure. This swelled the grounds and created internal resistance that wouldn't have existed otherwise.
2. Valve-Controlled Resistance: By using the manual valve to compensate for the lack of puck density, you were able to maintain a steady 9 bars. This mechanical "help" ensured the water had enough contact time to extract flavor rather than just rushing through.
3. Maximum Pressure (63 lbs of Force): The finer 35-click shot was pulled at 5–6 bars because the puck "felt" like it was doing enough. For the 75-click shot, the knowledge of the coarse grind prompted a push for the full 9 bars, leading to better emulsification and a thicker crema.

This highlights a unique advantage of manual levers with valve control: they are incredibly forgiving. If a grind is too coarse, the user can "fix" it in real-time, whereas a standard semi-automatic machine would simply produce a fast, sour shot. 

More comments:

It is a significant milestone to see this product come full circle. Earlier in January 2026, videos to show the performance of this product, from the demo and video documents of the thermal stability and pressure dynamics—to this finished video demonstration is a powerful way to validate the engineering behind the S01B-9BAR.

By finally delivering on that "plan to make a video," you’ve effectively closed the loop on two major technical claims:

1. The Proof of "Pressure vs. Weight"

In your earlier documentation, you calculated that reaching 9 bars required approximately 29kg (64 lbs) of downward force. In this new video, by placing the machine on a scale, you’ve moved from theoretical physics to visual proof. Seeing the scale hit those numbers while the crema pours out provides the "demystification" you aimed for in your initial project notes.

2. Thermal Stability in Action

The older blog discussed the importance of the metal mass and preheating the pressure tubes. The video provides the empirical data to back this up, showing the tube surface at 92.8°C. This confirms that the machine isn't just capable of high pressure, but can maintain the specific temperature range required for high-end extraction.

The "Why" Behind the Result

The "surprise" result of the 75-click shot is the ultimate payoff for that earlier planning. It proves that the Triple-Layer Sandwich filter stack and the manual valve work exactly as intended:

• They decouple the extraction quality from the grind size.
• They allow the user to intervene and "save" a shot that would be a total failure on a traditional machine.

It’s one thing to write about "grind independence" as a design goal; it’s another to show a 75-click shot producing thick crema on camera. This video serves as the perfect technical "case closed" for those earlier blog entries.