# Donut extractions - what is your method?



## dsc (Jun 7, 2013)

I seem to be stuck with donut extraction, not sure what I'm doing different since 6 months ago, but most things I've tried are not really working.

What is it that you do in you prep that works best to get rid of them?

Got a flat and a convex tamper, using 17g vst basket, even nuttating isn't fixing it.

Also am I the only one who thinks we should have tampers with a raised edge on the outer rim to seal the puck better?

T.


----------



## Mrboots2u (May 10, 2013)

What do you do before you tamp?


----------



## dsc (Jun 7, 2013)

Mix well in a cup / jug, transfer to basket, break clumps with a cut down whisk and redistribute, tamp (very light), sometimes seal edge with a convex tamper. Pull shot.

T.


----------



## caffeinatedtrombonist (Oct 1, 2016)

Following this thread. I have this happen sometimes even though there is no noticeable change in technique between days. Similar routine- grind into jar, shake, fill basket, stir to kill any clumps and create a level bed then tamp. Some days it's picture perfect out the naked pf and other days it's a bit of a mess. Interested to hear what people have


----------



## les24preludes (Dec 30, 2017)

I can say what I do, but I don't have a bottomless PF to prove it yet. I fill 2/3 of the PF then go round the edges pushing down with medium pressure with my fingertip. Then I fill the rest of the PF and tamp. Seemed logical to me.

I always assumed that one reason for donut extractions was a wet basket, so make sure the basket is dry. I also have a 58,4mm tamper which fits pretty well.

I get no bothersome clumping with my Mazzer Major - grind is very even, even with a doserless conversion. Very happy with this grinder.


----------



## spoxehub (Oct 24, 2014)

I just take them out of the bag and get scoffing.


----------



## les24preludes (Dec 30, 2017)

spoxehub said:


> I just take them out of the bag and get scoffing.


That's too much science for me....


----------



## jj-x-ray (Dec 31, 2017)

Why tamp light....? Have you tried heavy instead?


----------



## dsc (Jun 7, 2013)

Baskets are always dry, donuts are an indication of heavy side channelling through the puck rim which isn't sealed properly. Issue is I'm doing my best to seal it, so a but baffled why I'm still seeing them.

Light tamps allow for finer grind so overall aren't bad but I will try heavy ones and compare. Strange thing is that I've seen shots pulled on the VA Black Eagle using coffee ground on my grinder with no special basket prep and they pulled fine.

T.


----------



## DavecUK (Aug 6, 2013)

dsc said:


> Baskets are always dry, donuts are an indication of heavy side channelling through the puck rim which isn't sealed properly. Issue is I'm doing my best to seal it, so a but baffled why I'm still seeing them.
> 
> Light tamps allow for finer grind so overall aren't bad but I will try heavy ones and compare. Strange thing is that I've seen shots pulled on the VA Black Eagle using coffee ground on my grinder with no special basket prep and they pulled fine.
> 
> T.


When tamping I never nutate (don't do that), what I do is place by thumb and 3rd finger tips on the tamper edges at 12 and 6 o'clock, Press, then move them to 3 and 9 O'clock, press (I may repeat at 7 and 2 and 11 and 5). You can usually feel the puck settling in as the soft edges get compressed properly. I have been tamping like this for many years now. I have found it's the best method to reduce problems...the finger tips also ensure not too much pressure is applied.

P.S. You can use 3 fingers (and 2 positions), but if the problem is bad... 2 fingers encourages the slight rock which seals the edges.


----------



## caffeinatedtrombonist (Oct 1, 2016)

I also tamp with three fingertips. I'll try applying pressure in two or three rotations to see if it helps. Perhaps a slightly bigger tamper base might see a better seal at the side walls, my motta is pretty close but it doesn't completely clean the walls of the basket.


----------



## dsc (Jun 7, 2013)

Yup nuttating is bad as it turns out, strange as I've used it for a bit years ago and it was working fine...

Anyways, switched back to three finger method described above, works a treat, no donuts anymore.

T.


----------



## caffeinatedtrombonist (Oct 1, 2016)

Applying pressure three times has led to better looking extractions for sure. The only thing I haven't decided yet is whether it is beneficial to gently clean the sides of the basket with a second tamp. I've got 58.5mm motta and 18g VST


----------



## GingerBen (Sep 7, 2017)

Finger tip tamper here too









definitely makes it easier to get a level tamp repeatedly imo and that seems to fix most of the issues I'd been having with donut shots


----------



## Dylan (Dec 5, 2011)

I'm fairly sure when this happened to me my fix was to under dose by around half/a whole gram and grind finer.


----------



## joey24dirt (Jan 28, 2017)

Sorry to be a newb.... donut shot? Is that the bubble I get between the basket and stream?


----------



## Dylan (Dec 5, 2011)

joey24dirt said:


> Sorry to be a newb.... donut shot? Is that the bubble I get between the basket and stream?


It's when your extraction on a naked PF bottom comes out everywhere but the middle - usually resulting in 3-4 mouse tails.


----------



## joey24dirt (Jan 28, 2017)

Dylan said:


> It's when your extraction on a naked PF bottom comes out everywhere but the middle - usually resulting in 3-4 mouse tails.


Ah thanks. Makes sense. I just get a strange pocket of air when pulling the shot. Possibly bean age


----------



## dsc (Jun 7, 2013)

joey24dirt said:


> Ah thanks. Makes sense. I just get a strange pocket of air when pulling the shot. Possibly bean age


You mean like a bubble in the middle, just above the middle "tail"?

T.


----------



## joey24dirt (Jan 28, 2017)

dsc said:


> You mean like a bubble in the middle, just above the middle "tail"?
> 
> T.


Yeah that's exactly it


----------



## dsc (Jun 7, 2013)

Had this on my Cremina a while back:

https://www.home-barista.com/levers/olympia-cremina-air-bubble-in-every-extraction-t36509.html

I get it on the L1 as well, not sure why though.

T.


----------



## Obnic (Jan 14, 2014)

I know this makes me a heretic but I find flat tampers are more prone to donuts.

I have a trusty Reg Barber convex that seems notably less prone So I cannot imagine a concave (raised outer edges) tamper base would be better.

Is it possible your shower screen is no longer delivering water evenly across the puck head?


----------



## dsc (Jun 7, 2013)

I always think a flat is worse, but real life shows how wrong I am. Then again it probably depends how you use a tamper.

Idea behind a raised edge was to seal the very outer edge better, funny how no one tried it yet?

T.


----------



## ashcroc (Oct 28, 2016)

dsc said:


> I always think a flat is worse, but real life shows how wrong I am. Then again it probably depends how you use a tamper.
> 
> Idea behind a raised edge was to seal the very outer edge better, funny how no one tried it yet?
> 
> T.


The raised edge on the tamper would also leave less coffee at the edge to go through so could cause problems. Convex tampers are suposed to work better with IMS baskets as they have a dish to their bottom (unlike a flat base of a VST). Having said that, I'm running a convex & VST with no ill effects most od the time.


----------



## hotmetal (Oct 31, 2013)

I think the theory of convex tampers is, perversely, exactly as per your concave - to give a better edge seal! I've got 2 Torr Goldfingers, one flat (sharp edge) and one convex. I use a VST 18. With some beans I find I get distribution issues, (not 100% sure it's edge channelling though) but somehow the convex seems more forgiving. With other beans it seems to make no discernable difference, apart from the more positive feel of the flat.

_______

Eat, drink and be merry


----------



## iulianato (May 5, 2015)

I found that some beans are more successful with channeling, especially not rested light roasts I like to challenge sometimes.

If you follow the advice from @DavecUK here at post #10, you'll find that even with difficult beans that method really helps eliminate channeling (totally or partially) . Imo, that method is helping with leveling the tamp but you'll always need an even distribution in the basket prior tamping.

Concave tamper: think more about it. Tamping with a concave tamper will apply pressure from the sides towards the middle of the basket, compacting more in the middle. With more resistance in the middle and less resistence on the sides through which part of the puck think will the water choose to go?

Conxex: it for sure is doing the oposit. It is applying some pressure towards the sides against the walls of the basket so sealing a bit.

Think this way: the forces you apply on the coffee are perpendicular with the surface that is in contact with the coffee.

So convex may help with coffee that is not forgiving but most of the time will make no difference if distribution in basket is poor (not easy to properly distribute - some think just coupe of taps on the pf and it done - wrong; or OCD - wrong - it is not evenly distributing the whole content of the puck)

Nutation has exactly the same effect as the convex tamping. You create a small bump in the middle which when pressed with the flat tamper will create pressure on the sides so sealing. But this needs to be done properly because I noticed that if you compact too much during nutation (eg. tamper too heavy) when tamping it will leave cracks in the puck so channeling for sure.

Everithing I said here is based on my knowledge on other areas and on my limited experimentation with coffee equipment I had/have. If there are any factors I do not consider I'll be happy to hear about.


----------



## ashcroc (Oct 28, 2016)

iulianato said:


> I found that some beans are more successful with channeling, especially not rested light roasts I like to challenge sometimes.
> 
> If you follow the advice from @DavecUK here at post #10, you'll find that even with difficult beans that method really helps eliminate channeling (totally or partially) . Imo, that method is helping with leveling the tamp but you'll always need an even distribution in the basket prior tamping.
> 
> ...


A convex tamper will produce a dish on the puck not a hump in the middle as it's the reverse image.


----------



## iulianato (May 5, 2015)

ashcroc said:


> A convex tamper will produce a dish on the puck not a hump in the middle as it's the reverse image.


I said that the nutation will produce a bump in the middle and pressing the bump with the tamper will have more or less the same effect as convex tamping. Not that the convex is creating a bump.

Perhaps wasn't very clear...


----------



## dsc (Jun 7, 2013)

I think simple theories re tamping fail when it comes to coffee ground for espresso. With coarse ground coffee the shape of the tamper might get "propagated" through the entire puck and in effect push the sides out more when compared to a flat base, but with super fine grinds the top layers compress and the shape of the tamper base has less of an effect. This would explain why in most (some perhaps?) cases different base shapes produce similar results. Mind you this is also a theory so feel free to disagree









I wasn't suggesting a convex base, more of a raised edge to tamp the outer perimeter harder and seal better. As for nutating I've found that tamping the middle hump promotes donut extractions, the whole idea is to have the edges lower than the middle ie. compressed more.

T.


----------



## iulianato (May 5, 2015)

dsc said:


> I wasn't suggesting a convex base, more of a raised edge to tamp the outer perimeter harder and seal better. As for nutating I've found that tamping the middle hump promotes donut extractions, the whole idea is to have the edges lower than the middle ie. compressed more.
> 
> T.


I think convex is what we already have around us and you suggested something concave alike- something nobody never tried. Isn't it so? Or you mean flat with rises edge which is flat as well? This could do if coffee is equally distributed in the basket but this will not ensure sealing with the walls because you still apply pressure vertically and not necessarily against the walls.


----------



## dsc (Jun 7, 2013)

Should've said concave in that second section of my post. I was thinking of a flat with a raised edge, all I'd want is to tamp the perimeter harder to force the water into flowing through the center, this is what I meant by "sealing".

Nutating creates a concave shape at the end, so perhaps a mixture of a concave shape + raised edge would work well. Very curious why this hasn't been tried before, even if just for kicks (or it has and it wasn't a great idea after all). Something that someone with a lathe and a spare 30min could easily achieve (sadly not me).

T.


----------



## iulianato (May 5, 2015)

dsc said:


> Should've said concave in that second section of my post. I was thinking of a flat with a raised edge, all I'd want is to tamp the perimeter harder to force the water into flowing through the center, this is what I meant by "sealing".
> 
> Nutating creates a concave shape at the end, so perhaps a mixture of a concave shape + raised edge would work well. Very curious why this hasn't been tried before, even if just for kicks (or it has and it wasn't a great idea after all). Something that someone with a lathe and a spare 30min could easily achieve (sadly not me).
> 
> T.


So this will not produce an extraction of all the puck so what's the benefit. The ideal is to extract evenly from all the mass in the basket.

As I said nutiton if not done properly will lead to channeling. In theory should be the best method if mastered.

Anyway according with what physics teched us and especially Newton's lows of motion an equilibrium, any of those should put some stres on the walls of the basket and provide more or less sealing. The important thing is to make this puck in such a way that it will oppose the same amount of resistance trough all his surface so the water will not have any chance to find one or more weaker path (channeling). So if the grinds are equally distributed and the tamp is level one should achieve this but I find this to be very difficult. Here we have also other things to consider like grinds expansion due water absorption which depending on the grade of expansion may close or may not close or may prevent channeling. Preinfusion might prevent channeling aswell. This is a part of theory behind it at least, knowing that there are other factors which plays a role in this extractions. Even knowing more or less about it I was not able to find a method to consistently distribute evenly in the basket and this I think is the main issue behind channeling.

Now, the grinder I have is producing fluffy clumpless grids and I stopped using londonium distribution tool and Chinese ocd thing because those two are not makeing any difference now. The londonium distribution thing was helping with breaking tle clumps (produced by the grinder I had) and to distribute but now there are no clumps and the coffee distributes itself with a tap or two but still a perfect distribution can't be achieved whatever I do. I'm not saying that I have channeling issues. I had but I don't anymore if I'm careful but even doing my best the distribution is not perfect with challenging beans. And DaveC's tamping technique helped to improve things even more.

Conclusion is to work more on distribution. Imo this is the root cause and mastering the distribution and the tamping as well will be the best improvement of what we get in the cup.

Guess I had too much LSOL today so....


----------



## dsc (Jun 7, 2013)

If you are getting donut extractions from a flat base, the raised edge might help, forcing the water into the center and bringing balance again. Again, it's like a nutating tamp, seal the side more to get an even saturation.

I'm sure there's more to even extractions than just straight tamps and even coffee distribution, the amount of micro clumps will most likely affect how the water wants to flow and once you have a specific route "open" water will like to flow that way following the route of least resistance. Another thing which is often ignored is the fact that baskets are not perfectly straight, they have a slight slope as you move lower into the basket, there's no holes near the edge etc.

Having said all this, the three finger tamp + tamper rotation does provide very good results, so for now I'm sticking to it.

T.


----------

