Wednesday, 16 April 2025

Cremina lever profile (for darkly roasted beans)

The Olympia Cremina is a classic lever machine.

It doesn't have a spring.
Like most lever machines it exhibits a declining pressure profile.
This profile is a long shot ... about 45sec.
It uses a fine grind.

With dark roasted beans most of the flavour comes out early in the shot.
Towards the end, the shot is quite watery.

The Cremina uses  a narrow 49mm basket. 

It is characterized by a manual pre-infusion, a pressure ramp-up, and a subsequent pressure decline, all managed by the user's interaction with the lever.




I have a La Pavoni Europiccola which is quite similar.
I like to start the shot when the machine's group head is around 85C.
The end of the shot usually sees the group temp rising over 90c ... sometimes getting to 92-93c.
The classic La pav basket is 14g so you'd aim for 28 out.


Key Aspects of the Cremina Espresso Profile:
Pre-infusion:
The user initiates a pre-infusion phase by gently lifting the lever, allowing water to gently saturate the coffee puck at a lower pressure. 
Here the pressure rises to about 1 bar.

Ramp-up:
As the lever is further depressed, the pressure increases, typically ramping up to a peak pressure as the piston moves through the brew group.  (9 bar though I usually hit around 6-8 bar on my La pavoni)

Pressure Decline:
The user manages the lever's movement to control the pressure, causing a gradual decline towards the end of the shot. 



This is a really flexible profile.
You can pull this as a 1:1 ristretto for that classic Italian shot.
Sometimes I end the shot early at 30secs but you can also pull this with 12g  still at 45 secs.
These lever shots always finish at very low pressures.

This is a screen shot of a lever profile I have loaded into my modded (Gaggimate)
Rancilio Silva.

Red: Temp
Blue: pressure
Green: Flow

The flow peaks twice at 4g/s but drops to 1g/s 




I was using a 58mm to 49mm stepdown basket.

It has a Cremina Lever profile.
The initial dose is 18g. 
Out : 36g



Phases
A preinfusion for 25 secs (zero volume in cup)
  - soak - 15s, 1.1bar pressure
  - Ramp up to 3 bar, 4 s
  - ramp up to 6 bar, 4 secs
  - ramp up to 9 bar , 2 secs 
There should be no coffee in up at this point.



B. Brew stage (40 secs)
   - Ramp down to 8 bar. 10 secs. 6 g volume
   - Ramp down to 7 bar, 10 secs, 14 g volume
   - Ramp down to 6 bar, 10 secs, 26 g volume
   - Ramp down to 5 bar, 10 secs, 36 g volume


The Gaggimate is connected to Bookoo scales via wifi, and the pull shot stops precisely at 36g.







   



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variation 2

Temp settings: 
Higher brew temperatures for lighter roasts, lower brew temperatures for darker roasts

Preinfusion settings: 
    longer (slower flow rate) preinfusion for lighter roasts, 
    shorter (faster flow rate) preinfusion for darker roasts
    After preinfusion, pressure is ramped up to a maximum and then gradually declines. 

Pressure settings:
   Max brew pressure of 6-9 bar (I like 8-9 bar)
    Adjust decline to maintain a fairly steady flow rate (1.0-1.5ml/s) as puck erodes.

Pour time of ~30s (not including preinfusion)

Use the coffee dose suggested by basket manufacturer (but feel free to updose).
 "normale" brew ratio of 1:2 (adjust to your preference)

When starting out, I recommend getting a medium roast house espresso blend from an established specialty coffee roaster. This will maximize your chances of success. Then feel free to branch out to single origin coffees, uber-light roasts, etc.

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Tuesday, 15 April 2025

Q162 - sequential switch used as a Clock divider module

 The Q962 is a specific type of clock divider, likely a module within a modular synthesizer system.

 It's designed to take an incoming clock signal and produce a series of divided clock signals, meaning the output clock pulses occur at a slower rate than the input. This is useful for creating rhythmic variations and controlling other modules with different timing relationships. 

manual

Here's how a clock divider like the Q962 might be used:
1. Basic Division:
Connect the incoming clock signal to the input of the Q962.
Each output of the Q962 will provide a clock signal divided by a specific factor (e.g., /2, /4, /8, etc.).
These divided clocks can then be used to trigger other modules, such as sequencers, envelopes, or LFOs, creating different rhythmic patterns. 
2. Creating Rhythmic Complexity:
By using multiple outputs of the clock divider with different division factors, you can create complex rhythmic patterns that evolve over time.
For example, you might use a /2 clock to trigger a kick drum, a /4 clock to trigger a snare, and a /8 clock to trigger a hi-hat, creating a basic drum beat.
You can then experiment with different combinations and offsets to create more intricate rhythms. 

3. Combining with Logic Modules:
Clock dividers can be combined with logic modules (AND, OR, XOR gates) to create even more complex rhythmic variations.
For example, you could use an AND gate to combine the output of a /2 clock and a /3 clock, resulting in a clock pulse that only occurs when both clocks are high, creating a new rhythmic pattern.
4. Timing and Modulation:
Clock dividers can be used to control the timing of other modules, such as LFOs (low-frequency oscillators) or envelopes.
By using a divided clock signal to modulate the rate or amplitude of an LFO, you can create rhythmic variations in the LFO's output.
Similarly, a divided clock can be used to trigger envelope generators, creating percussive sounds with varying attack and decay times. 
5. Performance Techniques:
During live performances, clock dividers can be used to create dynamic changes in the music by switching between different division ratios or combining them in various ways.
This allows for transitions between different rhythmic feels or for creating build-ups and breakdowns in the music. 
Example:
Imagine you have a sequencer that is running at a certain tempo. You can use the Q962 to divide that tempo and then use the divided clocks to trigger other modules. For example: 
/2 (half speed): Could trigger a bassline or a longer melodic phrase.
/4 (quarter speed): Could trigger a percussive element like a tom-tom or a short melodic phrase.
/8 (eighth speed): Could trigger a hi-hat or a subtle rhythmic embellishment.
/16 (sixteenth speed): Could trigger a very fast, subtle rhythmic element.
By combining these different divisions, you can create a complex and evolving rhythmic landscape. You can also use the logic modules to combine the divided clocks in different ways, creating even more intricate patterns. 
In essence, the Q962, and clock dividers in general, are powerful tools for creating rhythmic complexity and dynamic changes in modular synthesizers.

Sunday, 13 April 2025

Best overall Profile - for dark roasted espresso

The best overall pressure profile for espresso, often referred to as the "Best Overall Profile" 
by some, (was made famous by Scott Rao)
typically involves 
a fast fill, a pre-infusion of about 2 bar, a ramp-up to 9 bars of pressure, followed by a gentle decline. 
I think its very similar to a classic lever espresso style shot but it never finishes at the low pressure that
the Cremina shot did.


This profile aims to balance extraction, avoid bitterness, and produce a well-rounded, balanced espresso.

Below is what this profile looks like on a decent DE1.

 The DE1 version  (for 18g in, 36 out) has 
1. a ramp up to 4 bar over 20 secs, 
2. steep Rise to 8.4 bar and hold for 10 secs
3. gradual decline to about 6 bar over the last 30 secs.
4 stop pour at 36ml


This is a really good profile for milk based drinks.