Ditting 807 Lab Sweet observations

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primacoffee
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#1: Post by primacoffee »

Hi, everyone!

My name's Ryan and I'm the Product Manager here at Prima. I'd like to jump in and help provide some clarity to 807 LS owners and those of you considering the grinder.

We've tasted coffee from over a dozen units, and also compared a hyper-aligned 807 LS with an out-of-the-box machine, and we actually preferred the flavor from the grinders that hadn't been tinkered with. If you decide to hyper-align, understand that you are changing the design of the Lab Sweet's intended flavor characteristics. That isn't necessarily the case with every brand/model out there, but we think it is true for the LS. for the best performance, use the grinder as it is out of the box. At most, use a torque driver at about 50% power to apply even tension to your burr screws and you're golden. And for goodness sake, do you not try to use your eyes to judge the quality of grind from an LS, use your tongue! The visual aspect of the LS grind will mislead you.

As a side note for anyone interested in using the LS for espresso:

It has been reported by some that their Lab Sweet cannot grind for espresso, even after zero calibration. We had about 4 reports of this, so I spent two full days with the grinders to get to the bottom of the issue and found something very interesting. The issue isn't that they don't grind fine enough (it'll choke your espresso machine without any problem), but the flow dynamics can be very unstable, even with careful puck prep. That didn't make a lot of sense, given that this is the same burr set included with the Mahlkonig Peak and E80 Supreme, so it was easy to blame it on an alignment issue. However, after hyper-aligning a LS, we found largely the very same behavior in flow dynamics. I spoke with Hemro about this and found that the design of the LS differs from the E80 supreme in a couple major ways: First, the aperture of the chute. The exit is larger on the LS than it is on the E80. Next, there is a second metal flapper in the E80 which provides additional resistance to the silicone flapper as the grounds exit the burr chamber. The LS has only a silicone flapper at the chute. These factors combined cause the grounds to be circulated inside the E80 burr chamber longer, producing more fines). In the LS, the grounds pass out of the burr chamber faster, creating a slightly more unimodal grind. We have particle analysis to confirm, but Hemro does ask that we don't make them public. In the graphs, you can see a slight increase of fines in the E80 which, by design, helps it maintain very stable flow dynamics. Ultimately, the LS is a highly unimodal grinder designed for filter coffee and that's why it's hard to make a more traditional espresso with it.

The metal flappers are cheap and easy to source, but keep in mind that this will make the LS retain about as much grounds as the E80 does and it sort of nullifies the single-dose nature of the machine (depending on how much coffee you're willing to purge.) If you go that route, we recommend buying two. One metal flapper didn't quite produce enough fines for our light roasts, but one (or none!) may work well in certain circumstances. (Especially if you're into turbo shots, try without)

Here is a link to three videos of espresso extractions with the LS: https://drive.google.com/drive/folders/ ... sp=sharing

Keep in mind these are straight 9 bar extractions and we did not test with any needle valve-style pre-infusion at finer grinds. With each flapper added we had to push the grind adjustment coarser by a few lines to get optimal flow.

1. Hyperaligned 807 LS w/ included silicone flapper only
2. Hyperaligned 807 LS w/ included silicone flapper + 1 E80 metal flapper
3. Hyperaligned 807 LS w/ included silicone flapper + 2 E80 metal flappers



-Ryan
Prima Coffee
888-837-7892
4603 Poplar Level Rd
Louisville, KY 40213
http://prima-coffee.com

Tjyven

#2: Post by Tjyven »

So what was the reason some users have problem grinding for espresso and others dont? Puck prep?

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primacoffee (original poster)
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#3: Post by primacoffee (original poster) »

It's hard to say. I know some have success with it, but we haven't been able to replicate an 'E80-style' flow dynamic across multiple grinders and multiple coffees without the use of the metal flappers. It could be the coffee, roast degree, recipe, espresso machine functionality, or even a difference of opinion in what 'espresso' should look like. But after many hours of testing alongside our technician, he and I are confident in ruling out alignment as the culprit for the problem.

-Ryan
Prima Coffee
888-837-7892
4603 Poplar Level Rd
Louisville, KY 40213
http://prima-coffee.com

coffeeOnTheBrain

#4: Post by coffeeOnTheBrain »

Thank you for the insights Ryan!
Did you test the burrs for flatness on the grinding side. In the production of the burr, when milling the grinding teeth, the machines drift from the set point for the height of the burrs. While this effect is perfectly normal it can lead to issues if it gets extreme, i.e.the machine drifts so fast that the proper tolerances are not met within a single burr and the teeth ending up having quite different heights, relatively speaking. When that happens you end up with a burr that can not be aligned, also the marker test might not be the best method to align such a lemon.

Usually a machine to mill the grinding teeth does not even need to be corrected more than once or a few times per shift, but if the machine actually needs repair it could be necessary to be set up for the correct tolerances twice for a single burr. Obviously this is not feasible in a factory, but a few burrs might end up delivered to the customer before the issue is even found.
I worked in a factory for motors when studying and I drove the engineer crazy who was responsible for my work. When I controlled the tolerances on a machine similar to one that mills teeth on a burr, I asked him to setup the machines tolerances every 20 minutes. That was actually needed to meet the given tolerances as the machine was quite old and probably needed service. After the 5th time he told me to not bother him anymore.
Frankly the factory was not close in production quality to a Ditting grinder ;)
Nevertheless, stuff like that can happen.

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primacoffee (original poster)
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#5: Post by primacoffee (original poster) »

coffeeOnTheBrain wrote:Thank you for the insights Ryan!
Did you test the burrs for flatness on the grinding side. In the production of the burr, when milling the grinding teeth, the machines drift from the set point for the height of the burrs. While this effect is perfectly normal it can lead to issues if it gets extreme, i.e.the machine drifts so fast that the proper tolerances are not met within a single burr and the teeth ending up having quite different heights, relatively speaking. When that happens you end up with a burr that can not be aligned, also the marker test might not be the best method to align such a lemon.
We used a dial meter for the rotating burr and a marker for alignment of the stationary burr.

I'll see if I can measure the teeth height here in a minute.


-Ryan
Prima Coffee
888-837-7892
4603 Poplar Level Rd
Louisville, KY 40213
http://prima-coffee.com

coffeeOnTheBrain

#6: Post by coffeeOnTheBrain »

primacoffee wrote:We used a dial meter for the rotating burr and a marker for alignment of the stationary burr. I'm unsure if we could accurately measure the heights of the cutting teeth using the dial meter jig, since the height is relative to the surface the burr is sitting on. How do you tell the difference between variation in height in the teeth vs variation of the surface the surface the burr is sitting on? Calipers, perhaps?

-Ryan
You are absolutely right it must be quite hard to measure, but using a real flat surface and good lighting is a way to actually see it.
Specialized precision mechanic shops might have a table like that. They also might have a better idea on how to measure this ;)

ira
Team HB

#7: Post by ira »

A comparator with the burr on a rotating horizontal spindle might be a reasonable approach to find out what's really going on, but a really good micrometer with carbide faces would easily measure the height of the points around the perimeter. Won't tell you a darn thing about what it mounts to, but a test indicator will give you a good idea of that.

ira
Team HB

#8: Post by ira »

Or maybe a test indicator with a tip like this, big enough and hard enough to drag across the points as long as you turn them backwards:

https://www.penntoolco.com/renishaw-sty ... 5000-7796/

coffeeOnTheBrain

#9: Post by coffeeOnTheBrain »

ira wrote:A comparator with the burr on a rotating horizontal spindle might be a reasonable approach to find out what's really going on, but a really good micrometer with carbide faces would easily measure the height of the points around the perimeter. Won't tell you a darn thing about what it mounts to, but a test indicator will give you a good idea of that.
Thank you Ira, you gave me all the right terms to google and learn a bit.
I liked this finding: https://www.mmsonline.com/amp/articles/ ... indicators

ira
Team HB

#10: Post by ira »

The other thing about this is, to do it right, you're looking at hundreds of dollars, probably over $500 if you want high quality tools and a really nice stand for the indicator.