Help with donut extraction

Beginner and pro baristas share tips and tricks.
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Italyhound

#1: Post by Italyhound »

I am using a versalab and an LM gs3.

The versalab grinds with a nice volcano pattern. If I use a convex or flat tamper, nutation or not - straight tamp or fill in - I am getting a dead center donut extraction every time. Otherwise the bottomless extractions are looking good now with an occasional spritzer.

I am using an HQ double basket with 18 grams. Same thing happened on the stock LM basket.

I am getting a shower screen screw impression on the wet puck which I would not think is a problem. However, might that be interfering with the center of the extraction given the persistent donut?

I can play around with lower doses but - before I attempt dialing in at lower doses - I am posting because 18 gms in a double HQ basket seems to be within range. I don't know if the GS3 screen screw is any bigger than other machines.

Thanks for any help. It might just save me from wasting more beans!
@evshack on Twitter

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Italyhound

#2: Post by Italyhound »

I will add one more piece. I put 18g in a triple basket and got the same central dead space.

Is it just the way the group screen of the GS3 puts out water? Not that I have studied water coming from an empty group but it does seem as if the volume of water in the center near the screw is not the same.

99% sure it's me of course :D
@evshack on Twitter

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tekomino

#3: Post by tekomino »

Post video of your prep routine and extraction. I think its only way to give you meaningful suggestion. Of all problems one might have with M3 I never had problems with donut extractions on none of my machines including GS/3...
Refuse to wing it! http://10000shots.com

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Italyhound

#4: Post by Italyhound »

As fate would have it, the donut quickly got swallowed by the cone this time. Typically it lasts longer as this extraction was a bit fast. However, the channeling is pretty horrific. :shock: Immediate sprayer.

It was 18g and a 4 sec preinfusion.
@evshack on Twitter

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tekomino

#5: Post by tekomino »

I recommend collapsing the cone insides then tapping basket down to settle grounds and then you level with finger and tamp.

Here is what I do:
Refuse to wing it! http://10000shots.com

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Italyhound

#6: Post by Italyhound »

Thanks for that video, Denis. I am not grooming the grounds prior to tamping; I'm just nutating away the volcano and tamping. I will try your technique. Your center space fills in very quickly as mine lingers.

Interestingly, as I said, I had learned that donuts were caused by an excess of coffee in the center. In this case, if anything, there is more on the periphery.

Appreciate the help. Pictures are worth 1000 words.
@evshack on Twitter

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tekomino

#7: Post by tekomino »

I don't think what you are seeing is donut per se. I consider donut a persistent dead non extracting spot in the middle that is there almost till the end of extraction. Yours flows through and I would not worry about it. Concentrate on taste now. How are shots tasting?
Refuse to wing it! http://10000shots.com

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Italyhound

#8: Post by Italyhound »

Thanks, Denis

The shots taste good but I want to improve them. My first task on the new machine was to work on the mechanical aspects of the extraction and from there I will play with grind/dose/timing. In general, they could use a bit more sweetness to them so I will tweak those parameters next.

Milk is coming along but is a learning process too. I like the foam knife 1 a lot. I have the burn me wand to install in the next couple of weeks.
@evshack on Twitter

cmin

#9: Post by cmin »

yeh that didn't look like a donut to me, came together and flowed out fairly evenly. Like Tek said a donut to me would be when the extraction looks and lingers in a circular shape on the outer perimeter and noticeably lingers there before the center extracts. For example sometimes when I've had the donut, on pre-infusion it just comes through enough to show on the outer perimeter while the center looks clean.

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cannonfodder
Team HB

#10: Post by cannonfodder »

Donut extractions are either too much coffee in the baskets, uneven distribution with a dense center or inadequate side adhesion in the basket leading to aside channeling. Since you are using a m3 you may want to try stirring your dose which will even out the center heavy distribution.
Dave Stephens