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Mignon Specialita - Crazy dial

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5.9K views 28 replies 12 participants last post by  forsh  
#1 ·
Two months old Mignon Specialita. I had been using the same beans for the last month and was getting consistent espresso shots with the dial set to 2 (around 18s for 15g).

Last night a friend brought some beans for grinding (~300g), so we played a bit with the dial and after finishing I set it back to 2 for my usual beans.

Next morning and the place is a mess because of channeling. I grind finer until I have the same results, and the new setting of the dial is now at 0.5.

Is that expected? Can anyone explain why this happens and is there a way to restore it back to the initial scale?
 
#2 ·
Did you adjust coarser for the bean your friend brought and did you have the grinder running while adjusting back to your original setting?

Is there a taste difference or is it just the marking on the dial that's different?
 
#3 ·
Yes, first coarser and then finer. Unfortunately, the grinder wasn't running at the time.

It's not only the taste difference, there is a lot of channeling and the brew time went down from 30s to 18-20s (for the same input & output 15gr in, ~32gr out).
 
#4 ·
Did you purge the grinder after the old beans? Sounds like you might just be retaining a lot of the old grounds and hence the shot is completely different.

usually have to purge a few grams whenever changing beans or grind setting to ensure all of that dose is of the same consistency
 
#8 ·
Hi Green Bean,

Going courser without the grinder running should be fine, but going finer might cause for some jamming so always best to run the grinder at the same time (so I was told somewhere.) I'm not sure if it causes a bigger issue as I believe you can always dial courser again and that will resolve the jam but it's a bit of a heart in mouth "oh shit, why is my grinder not working" kind of moment!
 
#9 · (Edited by Moderator)
You want to have the motor running when you adjust finer so you don't cause the burrs to jam (I don't for fine adjustments) you don't need to do it for adjusting coarser.

I think your fast running shot is due to retained coarser grinds, purge some and get yourself back to base, you shouldn't be wildly out from your previous setting.

Some good advice I've had is to not frequently make adjustments unless a defect is obviously caused by grind. If you are not purging there will always be a few grams of your previous grind setting mixed with the new and you will be forever chasing your tail. Try a run of shots and see if they are ok then decide what to do with it - sometimes a shot was just bad by itself, this will help you see the wood for the trees.
 
#10 ·
Could be retained grounds as mentioned.

If you adjust finer without the grinder running I was thinking the threads on the adjustment might have slipped against pressure from grounds trapped between the burrs but it's just a guess and I don't know if that's possible.
 
#12 ·
I was reading there was a seemingly bad batch of grinders recently they were taking longer to grind etc...

My new Specializa (2 days old) grinds 15 grams in 8.3 secs set at 2.8 ish on the grind scale. Your grinder seems to be taking quite a long time. The unit shipped with 9 seconds being a double so I would expect small variables around this.

18 secs for 15 grams sounds similar to those that I was reading were the bad batch so it might be worth checking with the retailer you purchased from that your machine is working properly.
 
#18 ·
Is it important to have the grinder running and beans feeding through whilst adjusting the grind dial finer?
It's only important if there are beans in the burr chamber as they can get squished and jam the grinder.

There is no need to have beans feeding through. It can just be quite a hassle to empty the chamber and block off the hopper everytime you want to adjust the grind finer. It's far easier to just waste a gram or two of beans.
 
#19 ·
Just a thought. As I've not tried it and don't know the answer. But does the adjuster refuse to move if there was a blockage or is there clutch type mechanism to allow the adjuster to move but not move the burrs with enough pressure to prevent damage if you were to force it? I was just thinking if there was it would explain the vastly different grind settings for the same bean when adjusting fine for espresso to coarse and back to fine again without running the grinder.
 
#20 ·
I think it's a little more simple than that - if you go way coarse you can end up with a large piece of coffee trapped between the burrs which will stop them moving. You go finer with the burrs moving to literally grind yourself finer.
 
#21 ·
Thanks Kjk, yes I understand that. What I was trying to ask was with a piece of coffee trapped between the burrs, which would stop them moving closer together would this prevent any movement of the grind adjuster (assuming the grinder is not running), even if it was turned with more force than is normally needed? Just trying to understand why moving the adjuster to a coarse grind setting and then back to the exact same position used previously would yield different results. (If the adjuster is directly linked with no slack in the adjuster, the burrs should return to the same position. If coffee grinds were stuck this should prevent the adjuster returning to the original position in the first place with the grinder off unless a clutch system to prevent damage was integrated into the mechanism (allowing the adjuster to move without movement in the burrs, (like a break out system).. I'm sure that's not the case as it would be quite complicated.
 
#22 ·
@FlyingPianist I don't think so, as grind adjustment is achieved through movement of a screw thread, sounds like an awfully complex solution to an unlikely problem - with a dial that small you'd need some impressive grip strength to generate that amount of torque.

@trapatsas your coarse grind session was with a significant amount of beans. It may be a combination of a lot of retention of the coarse grind and you are getting some exchange in your shots today. Clive Coffee have quoted 4g of total retention for the grinder but I'm not sure how long it would take you to completely exchange out a differing grind size. I notice it takes at least one, probably two shots to get consistency following a change in grind - and that is for a minor change for espresso (you've described a change in orders of magnitude). How many shots did you pull this morning?
 
#24 ·
@FlyingPianist I don't think so, as grind adjustment is achieved through movement of a screw thread, sounds like an awfully complex solution to an unlikely problem - with a dial that small you'd need some impressive grip strength to generate that amount of torque.

@trapatsas your coarse grind session was with a significant amount of beans. It may be a combination of a lot of retention of the coarse grind and you are getting some exchange in your shots today. Clive Coffee have quoted 4g of total retention for the grinder but I'm not sure how long it would take you to completely exchange out a differing grind size. I notice it takes at least one, probably two shots to get consistency following a change in grind - and that is for a minor change for espresso (you've described a change in orders of magnitude). How many shots did you pull this morning?
I finally removed the lid and unscrewed the upper part and then cleaned all the coffee from inside the grinder. Now seems that is returning back to the old settings. I grinded at ~1.3 and it was too fine. So, tomorrow will grind a couple more shots and aim for coarser. Retention could have been the actual problem.

Only odd now is the grind duration. Do you have the hopper always full or you just put just the beans for the shot?
 
#23 ·
This grinder setting is absolute garbage. I've been using it for a year now and I'm always fearful of changing my grind setting. It's so hard to find good setting and very annyoing when u forget how many turns did you do.
 
#26 ·
To come back to the topic of retention and exchange - here's a real world example from this morning. I was playing around with a lighter roast yesterday and although I closed the hopper collar and ground off the remaining beans the first shot of today included a considerable amount of coffee from yesterday.

You can see this on the left hand side of the grounds in the first photo - I use a dosing cup so these would have been some of the first grounds out. Second photo you can see this difference in the spent puck.

My wife still loved her morning milk drink...



 

Attachments

#27 ·
To come back to the topic of retention and exchange - here's a real world example from this morning. I was playing around with a lighter roast yesterday and although I closed the hopper collar and ground off the remaining beans the first shot of today included a considerable amount of coffee from yesterday.

You can see this on the left hand side of the grounds in the first photo - I use a dosing cup so these would have been some of the first grounds out. Second photo you can see this difference in the spent puck.

My wife still loved her morning milk drink...

View attachment 54659

View attachment 54660
The amount of retention... surprising!
 
#29 ·
With my Specialita I get about 15g in 14 seconds. I have no complaints though. I seem to get a consistent grind and get very little retention. My 0 point is dead on 0 and I tend to start dialling in just under 2.