Versalab M3 Grinder - Page 5

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AndyS

#41: Post by AndyS »

Abe Carmeli wrote:Thanks for the scale Jim, nice Job. I created a similar one using word, but I think a more appropriate one would be a scale printed on translucent tape. I'll see what I can do about that.
Good idea, print it on this:
http://tinyurl.com/abxaj

...although it's not self-adhesive.
-AndyS
VST refractometer/filter basket beta tester, no financial interest in the company

Abe Carmeli (original poster)
Team HB

#42: Post by Abe Carmeli (original poster) »

AndyS wrote: Good idea, print it on this:
http://tinyurl.com/abxaj

...although it's not self-adhesive.
Yeah, I was just thinking about that. I'll stop by Office Depot today to see if they have any self adhesive transparencies.
Abe Carmeli

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Abe Carmeli (original poster)
Team HB

#43: Post by Abe Carmeli (original poster) »

DAY 4

Today I was trying to determine the optimal Barista technique for the Versalab M3 grinder. Let's see some pictures:

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Uneven distribution half way into the grind

The distribution out of the grinder is not always perfect as we see in the image above. (I am nitpicking here, of course). The photo was taken half way into the grind of a 14 grams basket. This does not happen on every grind but on about 50% of them. I found that a good way to fix it is simply to turn the basket or P/F 180 degrees halfway into the grinding session.

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Uneven distribution out of the grinder - Full Basket

Dosing

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An under-dosed basket

The above picture shows an under-dosed basket. Leveling at this point will leave the center of the basket less dense and may cause uneven extraction.

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A good dose

You don't want to get it any fuller than the above picture.

Leveling

Moving to the Barista's leveling technique, I produced the best results using a 1,2 North South flat sweep across the rim with no downward pressure at all. Avoiding downward pressure is key. Since the M3 does not produce any clumps, there is no need to apply downward pressure to break them, or to redistribute the grounds. You want to move the mound and keep its density as it fills up the little crater left in the middle.

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Leveling the puck: one flat sweep north to the edge, and one south

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I call it Schomer's Crater. Don't do that.

The above image is a result of bowing your finger when you level. It creates uneven density - the center of the puck is more dense. This will slow down the extraction from the center. That distribution technique which works with all other grinders, does not work well with the M3. The grounds are already at a state of almost perfectly even density right out of the grinder, and the Barista's job is to mess as little as possible with it.

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My preferred method of leveling - no downward pressure

I found that tapping the p/f straight down against the counter, halfway or 3/4 way into the grinding session allows me to control the final dosage amount and still keep even distribution.

This is not the only way to work with this grinder, but I found it to be optimal for my usage at this point.
Abe Carmeli

Abe Carmeli (original poster)
Team HB

#44: Post by Abe Carmeli (original poster) »

DAY 5

After shamelessly drooling all over the Versalab M3 for four days, today is judgement day for that little engine that could.

The Shortcomings

Where is My Dial Scale?

Do you know of any grinder without a dial scale? Do you know of any $1,2500.00 grinder without a dial scale? Do you know of anyone who could not use a dial scale? (These are rhetorical questions, and if you do, please do not spoil my rant here :)). It is a serious flaw and I must say, inexcusable. Can you fix it by creating your own paper scale and attaching it to the dial? Yes, kind of, but it looks hokey, it is prone to get dirty with grinds, and it is just unacceptable.

Can you Hold that Dial for Me?

This one is a first for me. The Mazzer Mini, and many other grinders have their dial spring loaded, so the threads are always under pressure. This makes it easy for the dial to hold its place, but more importantly, to consistently repeat its performance after a change. In other words, if I dial 3 to grind Harrar then move to dial 4 to grind Cerrado, and then back to 3 to grind Harrar, the grinder will accurately repeat the grind size for the Harrar, and my shot time will be as it was the first time around.

That little convenience makes all the difference in the world if you are a home user and enjoys drinking variety of coffees at a time. Creating a dial stop chart for each coffee saves tons of coffee and frustration. The M3's dial is not spring loaded, and it appears that the wiggle room between the threads is causing the dial to lose its consistency. I've waisted a lot of coffee that way. The dial locking knob pushes a little rubber "break" against the threads, and if you do not consistently tighten it at exactly the same pressure, you will get the dreaded dial all over the place.

These are the big two shortcomings on my list. Can they be fixed by us users? I invited Sean Lennon to Join this thread, and show us the light. Sean is a Robotics Engineer with 20 years of experience, and a fantastic contributor to the coffee community. He is going to post an interesting solution to both problems later today, so stay tuned.
Abe Carmeli

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another_jim
Team HB

#45: Post by another_jim »

Abe Carmeli wrote:Can you fix it by creating your own paper scale and attaching it to the dial? Yes, kind of, but it looks hokey, it is prone to get dirty with grinds, and it is just unacceptable.
I'll have you know my strip is coated in plastic; and it looks a lot less hokey than the bubblewrap basket holder:

Image

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another_jim
Team HB

#46: Post by another_jim »

Abe, Andy -- I have an odd request, please bear with me. I'm spending my time doubling up on all my espresso making, making a shot each from the mini and the m3, and tasting a bit of each. Since this is my daily consumption, I'm making macs and cappas as well. It's no sweat pouring the milk into both cups after taking the sips; so I've been comparing these too.

I don't want to give anything away until I've racked up about 20 to 30 comparative shots over the next week, but I'd like you to also try some milk drink comparisons if you normally make these.

Abe Carmeli (original poster)
Team HB

#47: Post by Abe Carmeli (original poster) »

I'll have you know my strip is coated in plastic; and it looks a lot less hokey than the bubblewrap basket holder:
Jim,

Plastic or not, your strip's hokeyness remains intact and unchallenged :)
Abe Carmeli

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lennoncs

#48: Post by lennoncs »

Hi all,
I was talking a bit to Abe today about the issue he was having with creep in the adjusting barrel after tightening the lock screw. I grew up in the family business of machine tools and precision tooling, so my take on statements of "precision grind adjustment" made by manufacturers may seem a bit harsh to some. I would only start to consider precision adjustments to be those that are able to be reproduced within a few tenths (.ooo1) time after time. I defer to the experts on grain size for optimum extraction to give an exact size of the grains that we want (any time now Jim :D )

I do not have an M3 to take apart and look at but,
Here are my observations to date:

What is the bearing configuration supporting the mainshaft (duplex pair? Angular contact W/preload?) And how stable is the burr from being moved off axis?

What is the composition of the "solder" holding the wiper together? (this is not nitpicking...some of us spent years using red-lead for gear rubs and are exposed to heavy metals too much already)

Why do we care if the angular displacement of the barrel is calibrated? The clearance in the threads makes this a ballpark figure anyways. What we really care about is the actual axial movement of the burrs relative to each other. Why not use a dial indicator on the top of the funnel? Or some other part that reflects this relative motion. You can buy precision in the form of a dial indicator for very little money that exceeds the precision of the machine that built the M3 (I am talking about a ~$50 investment).

Go out and buy a Starrett "Last Word" or similar unit and the appropriate one of dozens of clamps/brackets available to mount it and use it to read the ACTUAL position of the barrel not some approximation. Remember; a thousandth of an inch is a significant percentage of the particle size we are trying to reproduce.

I have included a really lousy job of approximating what I am talking about below (MS Word, sorry)


Cheers
Sean

P.S. Looks like a really nice unit, I am going to have to crash Abe's place to rip his apart :D

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lennoncs

#49: Post by lennoncs »

Federal makes a superb short range digital unit that allows the display to be rotated independently of the plunger. You can also set it for analog type display or digital with analog marks as shown below. I currently use one of these on my Mazzer SJ. I run the burrs down to contact and zero the indicator and the from that point I have an exact display of my actual burr clearance and all I have to do after re-assembly is repeat the zero procedure and I am set. No more fiddling for a number of shots for the perfect setting and I now have a chart that is accurate after complete disassembly for cleaning because it is an actual number.

Cheers
Sean

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Abe Carmeli (original poster)
Team HB

#50: Post by Abe Carmeli (original poster) »

another_jim wrote:
I'd like you to also try some milk drink comparisons if you normally make these.
Jim,

I can't help you there, since I don't drink milk. But I'll be doing shot comparisons this week, and will wait for your report before I publish mine. I don't know anyone who can do as good a job at it as you.
Abe Carmeli