Fiorenzato-Pietro hand grinder

The Pietro hand grinder, made by the Italian company Fiorenzato, is a premium manual grinder featuring 58mm vertical flat burrs, designed for single dosing to produce a clean and subtle cup of coffee. 

It's known for its innovative design, including a unique ergonomic and retractable lever system and magnetic dosing chamber, which allows for precision, zero retention, and ease of cleaning. 

The grinder is available with 2 different burr sets for multipurpose or filter.

 

Key Features

Vertical Flat Burrs:

The Pietro is unique as the only hand grinder with vertical 58mm flat burrs, a design that promotes consistent performance and precise extraction. 

Zero Retention:

The design ensures that no coffee grounds are retained in the grinder, leading to a cleaner cup and more efficient use of beans. 

Ergonomic Design:

It features an innovative, ergonomic design with a retractable lever for comfortable and precise use. 

Magnetic Dosing Chamber:

A grounds container with strong magnetic buttons collects the coffee, making it easy to detach and use. 

Premium Build Quality:

Manufactured in Venice, Italy, the grinder is built with premium materials and a robust design. 

Specialized Burr Sets:

You can choose between the "MultiPurpose" burrs for a full range of brewing, or the "ProBrew" burrs, optimized for filter extractions. 

Benefits

Exceptional Clarity:

Produces a noticeably cleaner and more subtle cup of coffee, allowing for subtle tasting notes to become more apparent. 

Precision Grinding:

The vertical flat burr geometry provides perfect extraction for a superior coffee experience. 

Ease of Cleaning:

The grinder is designed to be easy to take apart, clean, and set up. 

Stylish and High-Quality:

Its aesthetic and craftsmanship make it a beautiful and durable addition to a countertop. 

Who is it for?

The Pietro is designed for discerning coffee enthusiasts who are looking for a high-performance, specialized hand grinder for single-dosing, and who appreciate a blend of innovative engineering and premium aesthetics. 

3D printed stand and funnel

The Pietro hand grinder has approximately 15 microns of burr distance adjustment per click of its numbered dial. This adjustment is consistent across different burr sets, including the standard M-Modal and the Pro Brewing burrs, providing users with precise control over their grind size for espresso, filter coffee, and other brew methods.

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Key Details

15 Microns per Click:

Each click on the Pietro's intuitive adjustment dial corresponds to a 15-micron change in the distance between the burrs. 

Burr Distance:

This micron value represents the actual physical change in the setting, ensuring a precise and repeatable adjustment for your grind. 

Intuitive Dial:

The numbered dial allows for easy and accurate identification of grind levels for various brewing methods, from espresso to filter coffee. 

Versatile Burr Sets:

This 15-micron increment holds true for both the standard M-Modal burrs and the Pro Brewing burrs (designed with Lance Hedrick), offering consistent precision regardless of your chosen burr set. 

There is a hack for making this stepless however I haven't felt the need to do this so far.

Spring lever pressure profile.

 A spring lever espresso machine's inherent pressure profile is a natural curve, 

starting with a gentle pre-infusion and quickly ramping up to a peak pressure before tapering off

as the spring expands. 

Skilled baristas can manipulate this profile by "pulling back" or "pushing through" the lever to control flow, enhance specific flavors, and achieve greater extraction uniformity compared to conventional, fixed-pressure machines.  

The Basic Spring Lever Profile

1. Pre-infusion:

The process begins with a gentle pre-infusion, using lower pressure (around 1.5-5 bar) to saturate the coffee grounds. 

2. Pressure Ramp:

Releasing the lever allows the compressed spring to expand, creating a quick spike in pressure (around 9-12 bar). 

3. Pressure Taper:

As the spring continues to expand throughout the shot, it exerts less force, causing the pressure to gradually decline. 

Note, there is a variation of this spring lever profile called "Londinium profile".

It is a adapted version of the spring lever profile that uses

a higher initial pre infusion pressure. For more info:

 + Londinium profile

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There are two types of spring lever machines:

Single vs Dual.

Single spring.

This is a Elektra La Casa.

The spring produces about 8 bar pressure 

This pic is from the Decent app

https://decentespresso.com/downloads

The Elektra is a really simple single spring machine, but it gives me some of the best tasting coffee I've ever had. The temp is closer to 90C, and I think the pressure lives somewhere between 7-8 bar.

Dual spring
Examples of dual spring lever espresso machines are the ACS Vostok and the Nurri Leva. They feature a double spring system for a consistent and repeatable extraction pressure. 

These machines incorporate a lever system with an inner and outer spring to provide a controlled and gradual pressure release, offering users precise control over the brewing process.  

How it works: 

Double Spring System:

Unlike single spring designs, a dual spring system in a lever machine uses two springs—an outer and an inner—to create a more stable and controllable pressure profile during the extraction.

Lever Operation:

When the user pulls the lever, it compresses the springs, which then provide a consistent, descending pressure to the coffee puck.

Consistency:

The dual spring setup helps to minimize pressure fluctuations, leading to a more repeatable and high-quality extraction.

Examples of machines:

ACS Vostok:

This machine is known for its use of a double spring system in its Lost Marco-clone group head, allowing for a repeatable style of extraction. 

Nurri Leva SA:

Another example of a modern dual spring lever machine, the Nurri Leva is praised for its beautiful design and innovative features, including the dual spring mechanism

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These are some graphs using the Smart espresso pressure profiler app

https://play.google.com/store/apps/details?id=hu.kavekalmar.sep&hl=en_AU

Profitec single spring

Pressure reaches 0.5 bar at 1 secs.

Stays there till 11sec. then steep ramp up.

Pressure hits 6.5 bar at about 17 secs followed with a gradual decline in pressure over 45 secs

Profitec dual spring

Pressure reaches 0.75 bar at 1 secs.

Stays there till 11sec. then steep ramp up.

Pressure hits 9 bar at about 18 secs followed with a gradual decline in pressure over 35 secs

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Faemia Faemia 1964

Its  a pretty old machine .

The highest pressure is I think about 5 bar. The coffee isn't perfect, but this machine is more sculpture and work of art.

Really long 20 sec preinfusion that initially rises to 1-2 bar then settles down to 1 bar.

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For fun I though I'd add a La Marzocco Leva x (graph below)

The X is a springless machine.

It utilizes a sophisticated electro-pneumatic system for brewing and pressure control rather than mechanical springs. 

Pressure reaches 2.5 bar at 3 secs.

Stays there till 10sec. then steep ramp up.

Pressure hits 9bar at about 13 secs followed with a gradual decline in pressure over 50 secs

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Coffee index. Click here :

https://djjondent.blogspot.com/2024/03/coffee.html

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R50 hand grinder - 34.5mm conical burr hand grinder

I received this unknown brand 34.5mm hand grinder.

The burr has 7 cores

I tracked it down to Aliexpress as a R50 hand grinder.

Chinese ? Some of the listings identify it as from a company called 9am.

Because of the 7 cores it will probably feed slower that a pentagonal or heptagonal burr set (but produce less fines).

It might be good for lighter roasts. ?

Heptagonal burrs require more force but potentially fewer rotations for grinding, potentially creating a faster grind with more effort, while hexagonal burrs require less force but more rotations for the same amount of grinding. Heptagonal burrs are known to perform well for lighter roasts and higher extraction brewing methods like pour-over and can also produce excellent espresso, whereas hexagonal burrs offer a more traditional and balanced flavour profile. 

The build quality was quite good.

I really like the magnetic catch cup.

It stays fixed when grinding much better than many of my other magnetically held grinders.

These are the steel burrs

It's fixed to the axel which I love as alignment is done in the factory.

It's two bearings which enhance alignment even more.

With the external click system I think this is great value.

about 100AUD

Two bearings on the shaft

34.5mm ??

This is how to open it up.

Go to the coarsest setting

Press this down 

then unscrew the nut

I still haven't seasoned the grinder, but so far, the espresso is Ok

It's all metal inside.

settings:

36 for V60/pourover

turn clockwise to go coarser

24 for espresso

turn

anticlockwise to go finer