Baratza Vario bad axis alignment (video)

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pmark

Postby pmark » Aug 15, 2019, 5:53 am

I've had this grinder for about 5 years now and it's never been very consistent. At the beginning it was used for espresso and worked well for some time, after I upgraded to a dedicated espresso grinder I've been using the Vario for filter but was never happy with it's quality. The brews I make with it seem over and under extracted at the same time i'd say, making me believe it's producing a lot of fines (that's my suspicion, I can't judge just by looking at the grinds - I could post a picture if that could be useful).

At one time about 2 years ago I sent my grinder to an authorized repair center and told them about its inconsistency. They told the grinder looked fine but they changed the motor belt anyways. I believe they simply test if the grind is able to grind and if it's not making any funny noises or anything but they don't brew any coffee and taste it. Again everything looks fine with the grinder it's just the quality of the output that is annoying. When testing afterwards I couldn't tell any improvement in the taste of my brews.
About 6 months ago I bought a new set of burrs, this time steel since they're recommended for non espresso methods.
Again I could not tell any improvements on my brews unfortunately. I know this grinder is capable of a much better quality.

I recently read this great topic The Alicorn: Achieving Precision Alignment with the Baratza Forté/Vario and thought I could give a try at aligning my grinder.
That's when I realized my lower burr might be running out of axis (as you can see on this video I took in slow motion (try watching it in full screen it's possible to see the misalignment of the lower burr)



Is there anything I could do to fix this issue? maybe the repair center tightened the belt too much? I've never tried opening it to inspect

At this point I'm very frustrated with this grinder, I paid about 450eur + 70 for the new burrs and it never delivered a great output. My feldgrind hand grinder produces a much better cup than it.

Thanks in a advance for any help or thought

namelessone

Postby namelessone » Aug 15, 2019, 8:09 am

You're making a lot of assumptions that the problem is the grinder. What grind setting (assuming your burrs are touching at 1A) and recipe are you using? What water and what kind of beans?
All grinders produce fines. You can control the amount of fines by grinding finer or coarser. You can make very tasty filter brews with far worse grinders so I doubt it's the grinder.

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Jake_G
Team HB

Postby Jake_G » Aug 15, 2019, 8:16 am

Hi Mark,

It's tough to say whether or not that radial misalignment is the source of your woes. It's not ideal, and I haven't seen it in any of the Forté grinders I've seen apart.

If could be a bent lower burr carrier, which would result in not only the side to side "movement" of the lower burr that the video depicts, but also a high and low spot on the lower burr. This could be confirmed by cleaning out the grinder and performing a marker test on the lower burr. If the marker is wiped off the lower burr all the way around when you bring the burrs to the touch point, there is a good chance that the burr carrier is not bent. In this case, your grinder can likely be brought into very good alignment, even with the radial misalignment you have.

The Forté lower burr carriers (which are a unique part from Vario, but similar) have very good manufacturing tolerances (less than 5 micron axial run out). I suspect the Vario shares these tolerances from the factory. If it turns out that you have a "point of contact" on your lower burr and some of it is not touching the upper burr as shown by a marker test, you will need to look into replacing the lower burr carrier. I would have your service center replace the grind chamber with the aluminum Forté chamber at the same time. This should allow you to achieve excellent alignment.

It is unlikely the belt tension could have impacted the burr carrier in the way the video shows. Excessive belt tension would most likely lead to a worn out bushing in the grind chamber, but the lower burr would still rotate true in that worn bushing, so long as the belt was holding tension on the drive pulley. Alignment relative to the top burr would be awful in this case, but the lower burr would appear just fine.

In your case, I would recommend clearing all the ground coffee out with a vacuum and then apply some dry erase marker to the circumference of the lower burr and then install the top burr and bring them to the touch point with the motor running to see how the axial/angular alignment of the bottom burr is. Based on those results, we can determine the next steps. A picture of the marker pattern on the lower burr after running this test would tell us a great deal.

Cheers!

- Jake

pmark

Postby pmark » Aug 15, 2019, 9:51 am

@ namelessone

Thanks for you answer namelessone you could be right.

My burrs touch at 2D.

I cleaned up my grinder and just tried to brew a cup of coffee using the aeropress with Tim Wendleboe recipe (link here: http://www.youtube.com/watch?v=ggCK_oOS_08).

The coffee I used is East Timor Duhoho from RAVE (respected UK roaster, more info on the coffee here: https://ravecoffee.co.uk/products/organ ... rticalTab3).

It's a light roast, fully washed. On the package the tasting notes are Raspberry, Pepper, Lemon and chocolate. I had one espresso this morning on my La Pavoni and it was delicious, very complex sweet coffee.

I used water at 95C (203F) like the recipe says. Grinded 14g at 4K on my grinder (not sure if you can get an idea but took some pictures of the grounds). I single dosed it (hopper not full)

Image

The tap water near Paris is very hard so I usually brew with Volvic:

pH 7
Calcium (Ca) 11.5
Chloride (Cl) 13.5
Bicarbonate (HCO3) 71
Magnesium (Mg) 8
Nitrate (NO3) 6.3
Potassium (K) 6.2
Silica (SiO2) 31.7
Sodium (Na) 11.6
TDS 109 (dry residue 130)

I waited it to cool down and tasted, it's very muted. If it was under extracted, from my experience with brewing it in espresso, this coffee should taste very acidic. My brew is neither acidic nor bitter just very muted. That's why I believe I could be under/over extracting at the same time.
One review from this coffee tells "Perfect for pour over, beautifully bright and light". Far from what I'm getting with my brew :(

This is how the puck looked. Looking more carefully now I believe the grounds should be finer at 4K. This look pretty large to me. Again the coffee should taste very acidic if under extracted.

Image

I have similar results with different kinds of coffees (either light or medium dark roasts). Also tried v60, cupping and French press nothing really interesting out of it.


@Jake

Thank you very much for your answer a lot of useful information here.
I cleaned it up again and vacuumed the grounds. I had a lot of grounds accumulated under the lower burr, not sure if this is normal:

Image


Even without the lower burr the carrier still is out of balance, similar to the video I posted.

I did the pen test this is how the lower burr looks after it, I'm not sure what is the conclusion here.

Image

namelessone

Postby namelessone » Aug 15, 2019, 3:54 pm

Looking at my notes, my grinder was zeroed at 1A and I was grinding around 5F for V60. For Aeropress I would use maybe 3 or 4F? I remember the mico/macro adjustments not being linear. i.e 10 micro is roughly same as 1 macro, which makes it harder to adjust setting. So set macro first and the micro in the middle and then you can tweak it up /down little. Going from 4 to 5 for example is actually not a very large change, maybe similar to 1 or 2 settings on my EK.

With Aeropress you can try steeping longer? I usually use the inverted method and steep for 4-8 minutes to get the most flavour out.

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Jake_G
Team HB

Postby Jake_G » Aug 15, 2019, 6:43 pm

pmark wrote:I cleaned it up again and vacuumed the grounds. I had a lot of grounds accumulated under the lower burr, not sure if this is normal:

This is typical without a spacer under the burrs to support them and fill the air gap beneath the screw holes.

pmark wrote:I did the pen test this is how the lower burr looks after it, I'm not sure what is the conclusion here.

The small region with the marker rubbed off indicates a high point. The lower burr carrier is likely bent. You could probably square up the lower burr with some shim stock and then perform the Alicorn alignment, but I would recommend having the service center replace it and install the updated grind chamber, as well. This would give you an excellent starting point. That said, if you're going to attempt the Alicorn, you may prefer to simply order the grind chamber and burr carriers and install them yourself.

In order to hope to have a good particle distribution in your grind, your burrs need to be parallel. Since the marker test indicates that your lower burr isn't even parallel to it's own axis of rotation, I would not expect your grind to be very good at all.

Cheers!

- Jake

baldheadracing
Supporter ♡

Postby baldheadracing » Aug 16, 2019, 9:51 am

If you want to try replacing the lower burr carrier yourself, then it is relatively straightforward, if a bit involved. Only drive belt tension and gravity are holding the lower burr carrier in place. Here's the procedure:
What I'm interested in is my worst espresso being fantastic - James Hoffmann

pmark

Postby pmark » Aug 17, 2019, 6:52 am

@namelessone, thanks again for you input, at the moment I'm 90% sure the issue is coming from my grinder. I'll do further tests soon with other grinders just to be sure.

@Jake_G, Thank you you've been really helpful.
It might be a good idea to order the Forté parts and put them in my grinder since they're more solidly constructed. I look a bit over the internet and couldn't find those parts neither in Baratza official website nor in Europe resellers. Any idea where I could find it? maybe I should just contact Baratza and try to order with them directly (could involve international shipping costs though)

@baldheadracing thanks, your video have been helpful. I disassembled my Vario this morning and I believe I found the reason of the play. I made a small video of it showing two pieces from the lower burr carrier:



I have zero experience with other grinders, anyone could tell me if this type of play is normal with the Vario? Should I order this two pieces and try to replace or it's not worth the try?

thanks in advance for your thoughts

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Jake_G
Team HB

Postby Jake_G » Aug 17, 2019, 9:16 am

pmark wrote:I have zero experience with other grinders, anyone could tell me if this type of play is normal with the Vario? Should I order this two pieces and try to replace or it's not worth the try?

That play is harmless.

As you can see, the drive sprocket plays the part of the "socket" that engages and turns the "bolt" which is the hex drive shaft on the burr carrier. The slop simply allows for ease of assembly and service. The carrier itself is positioned by the two bearing surfaces above and below the hex section.

From your earlier videos and the marker test, it strongly appears that burr mounting surface of your carrier is not true to the bearing surfaces (the shaft that mounts in the motor plate and grind chamber.) With your grinder disassembled as you have done, you should be able to quantify the issue and potentially get it corrected by a handy craftsman. I think the carrier is actually two pieces, with the aluminum portion that the burr mounts to secured to the steel shaft. You could verify with a magnet. At any rate, if you took this to someone with a hobby lathe, they could likely true up the burr mounting surface for you or, even better, pull it apart and get it reassembled properly.

I have friends with good tools, and they enjoy this type of thing, so I can generally get stuff corrected with nothing more than a few minutes of conversation as payment. For those without such useful friends, a 6 pack of beer goes a long way!

I have heard reports that if you send your grinder to Baratza for refurbishment in the states, it returns with the Forté grind chamber installed for a flat rate of around $85. Adding a new lower burr carrier should tip the scales much of $100, total. But that's on this side of the pond. I'm not sure how to make it work in the UK, but it's worth shooting Baratza a note to ask. With your level of expertise in how far you've disassembled it so far, I would not bother with having Baratza install anything unless they refuse to send you the parts directly.

I would recommend dropping the burr carrier into the grind chamber and verify that the wobble is still present with the individual components so you can be sure that the carrier is the cause.

Cheers!

- Jake

baldheadracing
Supporter ♡

Postby baldheadracing » Aug 17, 2019, 2:45 pm

Jake_G wrote:<snip>
I have heard reports that if you send your grinder to Baratza for refurbishment in the states, it returns with the Forté grind chamber installed for a flat rate of around $85. Adding a new lower burr carrier should tip the scales much of $100, total. But that's on this side of the pond. I'm not sure how to make it work in the UK, but it's worth shooting Baratza a note to ask. With your level of expertise in how far you've disassembled it so far, I would not bother with having Baratza install anything unless they refuse to send you the parts directly.

I specifically requested the Forte grind chamber as I was unable to grind fine enough with the grinder as-is (steel burrs). The grinder had five years of regular use. Part #'s of what they replaced here Baratza Vario, brew burr + metal grind chamber, espresso report

I believe that Baratza will ship parts outside the US, but the $85 refurbishment service is US-addresses-only. Parts PDF's are on the Baratza website: https://www.baratza.com/documentation/
What I'm interested in is my worst espresso being fantastic - James Hoffmann