Dave_I Senior Member Joined: 1 Dec 2009 Posts: 120 Location: Wisconsin Expertise: I like coffee
Espresso: Brewtus II Grinder: Baratza Mario Vac Pot: N/A Drip: Cheap coffee machine (can't... Roaster: None . . . yet.
Posted Wed Oct 20, 2010, 8:35am Subject: Donut Extractions Even w/ Smaller Doses, WDT, & NSEW Tamping
I got five lbs. of Redbird Espresso to fine-tune my technique. I am currently getting some consistent donut extracting. It has gotten better, however it is still there. Some details:
Grind: I'm using WDT grinding into the basket (but not the PF, I took the clip out), stirring w/ a needle (but there is little-to-no clumping w/ the Vario), and leveling with the flat side of a butter knife
Dosing: I have been trying smaller doses after getting donuts. However, I've been trying 15 and 16 grams and it still donuts.
Tamping: I have a flat Espro, and nutating does not seem to work for me for whatever reason. My basket is a double-shot basket with slanting sides. I have been trying NSEW tamping (30 lb. tamps on four corners) which seems to help, but I am still getting donuting & early blonding from the edge. I have also tried tapping straight down to compress the bottom of the puck and ensure no air pockets exist but that did not eliminate the problem.
At any rate, I am kind of at a loss for what to do here. As an aside, the first day I pulled shots with the current batch of Red Bird I ended up pulling looked just about perfect, tasted pretty good, just seemed like it needed more time to degas. After that it all went downhill.
Anyway, any advice on things to try? It just seems like I'm getting a little donut extracting, and some early blonding as a result, plus sometimes a pinpoint right in the middle of the puck. Still, it does seem to be getting better but I just can't seem to totally eliminate the donut extraction. I'd be open to anything that I should try, because it feels (well, tastes) close but is frustrating because every shot seems to have this problem.
Posted Wed Oct 20, 2010, 1:17pm Subject: Re: Donut Extractions Even w/ Smaller Doses, WDT, & NSEW Tamping
Just a suggestion but- how about bump your dose back up, grind a bit finer and tamp lighter. I have the best results with one straight down tamp with the slightest twist at the end,(I guess so nothing tries to stick to the tamper). My feeling is you're causing some of the "donut" or outer channeling with your tamp technique, and that a finer grind might be the first course of action needed. Just my 2 cents but maybe worth a try! Good luck to you, Ron
IMAWriter Senior Member Joined: 4 Jul 2002 Posts: 5,464 Location: Brentwood, TN Expertise: I live coffee
Espresso: Nothing at the moment Grinder: Vario-W,Preciso-Esatto/KyM... Vac Pot: Adcraft SS, Yama 8 cup Drip: Brazen.Chemex, Hario, Clever... Roaster: Behmor 1600, CO/UFO combo
Posted Wed Oct 20, 2010, 9:15pm Subject: Re: Donut Extractions Even w/ Smaller Doses, WDT, & NSEW Tamping
CoffeeRon Said:
Just a suggestion but- how about bump your dose back up, grind a bit finer and tamp lighter. I have the best results with one straight down tamp with the slightest twist at the end,(I guess so nothing tries to stick to the tamper). My feeling is you're causing some of the "donut" or outer channeling with your tamp technique, and that a finer grind might be the first course of action needed. Just my 2 cents but maybe worth a try! Good luck to you, Ron
Nice post Ron, especially enlightening those unfamiliar with the term "donut" extraction.
Edge channeling, as I call it, often (for me) used to occur because my distribution was faulty. Too much emphasis is placed on tamping, not enough on getting the coffee equally distributed in the basket.
I'd eschew the butter knife. and the WDT. Make sure the dose piles in the center, at least 5-6 mm over the basket rim, hopefully with a nice hill in the center. I like to tap the PF straight down lightly one time to settle the fluffy Vario grind a bit, then use my pointer finger, going lightly NSSN, EW/WE, making sure there is no space at the edges. Then a light leveling tamp, lift the tamper, check that the puck is level, and go for the 30#. (or lighter, as suggested, but be consistent!) At the end of the 30# tamp, polish without pressure.
BTW, THE WDT can be a great thing, especially with a triple basket, but is of little or NO value with a Vario, for the clumps are minimal, or non existent. thus there is no need to disturb your coffee. Do everything with the basket in the PF, so as not to disturb the puck.
Pull at 200f for Red Bird. I've ordered this fine coffee twice (5lb'ers). It likes a bit of overdose, a 28 second pull (17-18 gram) double, and a 1.75-2oz yield. YMMV.
Possepat Senior Member Joined: 18 Nov 2011 Posts: 6 Location: Halifax NS Expertise: I love coffee
Posted Fri Jan 20, 2012, 5:34am Subject: Re: Donut Extractions Even w/ Smaller Doses, WDT, & NSEW Tamping
Donut Extractions
I was having consistant donut extractions, irregardless of my grind, level/redistribution and tamp. So I took my basket out of the portafilter (bottomless with Elektra Double Basket) flipped the basket over, threw a straight edge on it and saw it had a curve to it. As it should this is not a VST calibrated basket, it is punched/stamped out on a machine so it stands to reason that this curve would be present.
So I used the but end of my plastic cremina handle to gentlly and gradually push the centre of the basket down to correct this, straight edge again... a little more pushing, straight edge.... SUCCESS, flat as a board!
Locked and loaded and was thrilled to see that my beads of espresso were starting MUCH more evenly all over the face of the basket including the centre which had usually given me dead spots.
OlivO Senior Member Joined: 18 Jan 2012 Posts: 17 Location: Toronto Expertise: Pro Barista
Espresso: La Marzocco GB/5 Grinder: Mazzer Maj
Posted Fri Jan 20, 2012, 8:38am Subject: Re: Donut Extractions Even w/ Smaller Doses, WDT, & NSEW Tamping
Keep variables constant and try different grooming techniques, keeping track of what worked better than others. The movement of the coffee as you groom your shot produces a kind of tetris effect, where particles or varying size fill in each others gaps. The more grooming, the more tetris. I started Stockfleth's technique a while back as the rotational grooming method seemed to work better at preventing channelling at the edges. You can still NSEW after this to produce a good result.
Is your tamper a good fit for your basket? If not, focus multiple strong tamps all along the perimeter of the puck, keeping the puck level. It's a pain, I know. Don't worry too much about the exact pressure of the tamp--it is negligible compared to the force of the water coming down on the coffee anyway.
Remember, you are trying to control pressurized water through a puck of coffee. You have to be anal as hell to get a perfectly even density all the way around the puck. Even then, water finds a way to be frustrating. Nature hates us all. In the end, a consistant application of a method, once a working one has been discoved, can really only guarantee you a statistical success rate.
Posted Mon Jan 23, 2012, 1:44pm Subject: Re: Donut Extractions Even w/ Smaller Doses, WDT, & NSEW Tamping
I've had consistent donut / side channeling and I've tried a few techniques to fix it. I still have a lot of experimenting to do since I recently cut my PF. I'd like to offer my solution but also welcome its critique. I'm not sure if it's the best solution. FYI, this is for a la Pavoni style lever machine, 49 mm basket. My solution at the moment is to give a convex distribution. I use a vario lid for this. Then I tamp with moderately hard pressure with my curved tamper (a decent metal one that came with the machine). Then I use a flat tamper (OE) and tamp with moderate pressure (slightly lighter). I think the effect is like the nutating motion except it's less risky/more balanced. This seems to counter the donut effect by compressing the outside more. The tamped surface should look kind of like this (flat sides with a concave center): –––\___/––– I'm not sure this is my permanent solution and it shouldn't be necessary to use 2 tampers, but it's working for me at the moment. I'm trying to decide what I like best since I'm hoping to get a reg barber tamper someday, and I have absolutely no idea if I want flat, US curve, euro curve, c-flat etc. Here is a picture of my 2 tampers:
OlivO Senior Member Joined: 18 Jan 2012 Posts: 17 Location: Toronto Expertise: Pro Barista
Espresso: La Marzocco GB/5 Grinder: Mazzer Maj
Posted Mon Jan 23, 2012, 2:08pm Subject: Re: Donut Extractions Even w/ Smaller Doses, WDT, & NSEW Tamping
Two tampers; I kind of wish I thought of that. I'm going to try that at the cafe to see what effect it has. It sounds like a great idea. I have both a concave and flat tamper at my disposal, so I'll keep you posted. The concavity could very well increase the density of coffee at the basket walls, making channels there a little less likely. Good idea.
calblacksmith Moderator Joined: 25 Nov 2007 Posts: 5,685 Location: Riverside, Ca, U.S.A. Expertise: I live coffee
Espresso: ECM Veneziano A1 Grinder: Many different commercial Vac Pot: 40s era Silex Drip: Milita, Bunn&Curtis... Roaster: Cast iron pan, gas burner
Posted Mon Jan 23, 2012, 3:15pm Subject: Re: Donut Extractions Even w/ Smaller Doses, WDT, & NSEW Tamping
Redbird likes to be pulled long and hot. Per the instructions on their site, Grind and tamp to produce a 25 to 30 second shot timed from the first drip at 198 to 200f.
This is a little different than the standard time when you start the pull advise but if you go by Jeff's advice, you get nice pulls.
I have a straight sided double basket in which I put 18 g of Redbird and I follow the above advice. As I use a Press point tamper with a flat head and a naked PF, I get a dead flat and even tamp at 30 pounds though the tamp is the least important part, it is very consistent.
I have moved away from my SJs and am using a Azoyken Cappricieo (sp) automatic grinder for dosing. It is a more dense than fluffy grind and the 18 g in my basket levels out to dead flat to the top.
Even then, I still can and do get doughnuts. They happen, but in the best situation, you get some pulls without it and they tend to be very good indeed.
In real life, my name is Wayne P.
Feed the newbs, starve the trolls and above all enjoy what you drink!
Posted Mon Jan 23, 2012, 3:20pm Subject: Re: Donut Extractions Even w/ Smaller Doses, WDT, & NSEW Tamping
Thanks! I'm very interested in other solutions too, Possepat's looks interesting. I have a lot of different baskets so it might be worth it. I have a few lever machines and the riviera (which i haven't repaired yet) has a flat-bottom basket. The hole density doesn't look as nice, but it's probably worth a try to use it in my Graziella first. It's a slow process to experiment with a lever machine like mine though, and there's a lot to try!
I thought a curved tamper would help push the coffee out, compress the sides and that would be enough, but that doesn't seem to be the case so that's what the second flat tamp is about. I'm not sure if the pre-tamping concave distribution/grooming is still necessary, but it seems to work.
Something to consider with the 2 tampers is the pressure. I mentioned that the second tamp is relatively lighter. Somehow I've drifted toward hard tamping (when I first got my lever, I was big on light tamping). I'd like to try light tamping, flat and with this double tamp and see how it goes.
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