# On "bitterness" and "over extraction"



## robashton (May 9, 2015)

Related to that other thread about high extraction and sweetness...

Can somebody tell me why I can with the EK do stupidly long brew times with fine grinds and not get something that tastes like arse (in my case, toning the acidity of that Square Mile from Kenyan right down and giving me a cup of "GIMME MORE" juice), and yet when I mention to this to one of my tame baristas they pull their face and go "won't that be super yuck?"

Could they also manage such things on their gear? Surely when you're going for super extraction you're always going get there if you leave it long enough even if your grinder is crap? Or do they fall short into that weird valley of bitterness unable to climb out the other side? Or is it just that you also need to use really good coffee for this sort of thing or run the risk of artifacts like roastiness and such and that's what we've always been used to? Why would one grinder taste good at 21% and another not? The wrong few %?

I'm looking for an explanation so rather than being looked at as if I'm stooooopid in the coffee shop I can say "well.... this is why my super long aeropress soak doesn't taste bitter"

This is similar to the whole coffee shot thing I guess, except there is finite time involved there and no doubt that weird uncanny valley?


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## Mrboots2u (May 10, 2013)

http://mattperger.com/The-EK43-Part-Three

http://mattperger.com/Extract-More-Better


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## robashton (May 9, 2015)

That's so out of date though



> Essentially, the EK43 can break coffee beans apart many more times without experiencing a drastically increased number of fines. This is one of the reasons why you can extract more with an EK43 without experiencing dryness or unacceptable bitterness.
> ​


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## robashton (May 9, 2015)

It's all just soluble material - with enough time - surely every grind would dissolve the same (before it went stale obvs)


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## robashton (May 9, 2015)

Are we really still at the point where we just go "hand wave", it's the EK43

[edit]

I just don't feel as though I have a suitable enough answer when questioned on my recipes by baristas, and as a result I get patronised because they've never had a proper EK43 shot or filter (Hell, I've barely managed many of those).

"It just does" is great and all, but as far as they're concerned I might as well be talking out of my arse.


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## MWJB (Feb 28, 2012)

High extraction only equals sweetness if it is even. It's easy enough to get a drip brew to 23-24% with just about any grinder, though most with a less even particle distribution will be sweetest (for that design) ~19-21%.

You're not always going to hit a super high extraction, it's not a given.

Immersions can be pushed up to their limit & taste sweet, but the extraction isn't as aggressive, nor quite as efficient as drip/espresso (percolation). A long steep in any brewer is going to be hard to overextract (by taste, not necessarily the %) as long as you have a declining temperature profile. Put 20g of coffee in your Aeropress, add as much, or as little water as you like, leave it to steep & when it hits 10%TDS jump on to your hoverboard, whizz over, and show me your holographic projection of your wristwatch/coffee refractometer/molecular transportation device! 

We are used to the idea that bitterness has a single, easily definable cause - it doesn't.

Some beans are easier to extract, as are the same beans roasted, or processed differently, but your EY target is more driven by grind distribution than bean quality per se.

The coffee shot thing is essentially treating an espresso machine as a 1 cup, flat bed, pressurised drip brewer - If you can hit 23% with an EK espresso at 2.35:1 ratio, by grinding coarser you should be able to hit that same extraction even more easily at much longer brew ratios...theoretically, down to any TDS, pretty much. They used to have a thing called a caffe crema, a long shot pulled on an expresso machine to replicate a filter coffee...similar idea to the coffee shot, but perhaps not aimed a producing the same sweet & highly targeted result. There have also been fast brew ESE pods & lungo capsules too. The long coffee from an espresso machine isn't directly related to high extraction, more to target strength, but the more water you pass through a puck/bed the better your chances of a high extraction.


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## MWJB (Feb 28, 2012)

robashton said:


> It's all just soluble material - with enough time - surely every grind would dissolve the same (before it went stale obvs)


No, only 24-36% is soluble material. The rest is insoluble cell wall.


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## robashton (May 9, 2015)

MWJB said:


> H A long steep in any brewer is going to be hard to overextract (by taste, not necessarily the %) s, add as much, or as little water as you like, leave it to steep & when it hits 10%TDS jump on to your hoverboard, whizz over, and show me your holographic projection of your wristwatch/coffee refractometer/molecular transportation device!


Granted.



> We are used to the idea that bitterness has a single, easily definable cause - it doesn't.


Okay - that's a good sentence, I can use and remix that sentence for great good.



> The coffee shot thing is essentially treating an espresso machine as a 1 cup, flat bed, pressurised drip brewer - If you can hit 23% with an EK espresso at 2.35:1 ratio, by grinding coarser you should be able to hit that same extraction even more easily at much longer brew ratios...theoretically, down to any TDS, pretty much. They used to have a thing called a caffe crema, a long shot pulled on an expresso machine to replicate a filter coffee...similar idea to the coffee shot, but perhaps not aimed a producing the same sweet & highly targeted result. There have also been fast brew ESE pods & lungo capsules too. The long coffee from an espresso machine isn't directly related to high extraction, more to target strength, but the more water you pass through a puck/bed the better your chances of a high extraction.


Yeah got that - the finite time thing here makes this easy to understand.

Ta - is useful.


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## robashton (May 9, 2015)

MWJB said:


> No, only 24-36% is soluble material. The rest is insoluble cell wall.


Yeah I get that - my point is that with every grinder this is the same number


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## MWJB (Feb 28, 2012)

robashton said:


> Yeah I get that - my point is that with every grinder this is the same number


Sorry, you lost me there?


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## robashton (May 9, 2015)

MWJB said:


> Sorry, you lost me there?


I mean - a whole bean has a total soluble content of 24-36%, the grinder does not change this - right? Unless we are saying that by bashing up the beans into tinier pieces we expose more of this soluble content and that with bigger bits of bean it's just impossible to dissolve it as fully - even with "infinite" time.


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## Mrboots2u (May 10, 2013)

robashton said:


> Yeah I get that - my point is that with every grinder this is the same number


"your EY target is more driven by grind distribution than bean quality per se."

Different grinders have different grind distributions = not tasty at 19% ey plus ( bitter )


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## robashton (May 9, 2015)

Mrboots2u said:


> "your EY target is more driven by grind distribution than bean quality per se."
> 
> Different grinders have different grind distributions = not tasty at 19% ey plus ( bitter )


Because less tasty bits have been dissolved than would have been otherwise?


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## Mrboots2u (May 10, 2013)

1.More even grind - more bits extract more evenly = tasty

2.Less even grind = some bits extract more , some bits extract less and to a bigger degree than 1


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## garydyke1 (Mar 9, 2011)

The question is :

Why does a 24-25% extraction shot/brew taste [most often] amazing via the EK43 but comparatively horrid via a Mythos 1/ Porlex / Uber grinder ?

My best answer - the narrow particle distribution spread. Any 'fines' are similar in size to the 'rocks'


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## garydyke1 (Mar 9, 2011)

The drinks made with the EK43 exhibit more bitterness when under-extracted than when technically 'over-extracted' in conventional terms


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## robashton (May 9, 2015)

[MENTION][/MENTION]



garydyke1 said:


> Any 'fines' are similar in size to the 'rocks'


But they're not - that's the latest thing from Perger or whatever, there are actually way more fines and they're absolutely tiny tiny and that's where all the flavour comes from - I feel as though there is no way you've missed this and therefore I've missed something here too.


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## Mrboots2u (May 10, 2013)

robashton said:


> But they're not - that's the latest thing from Perger or whatever, there are actually way more fines and they're absolutely tiny tiny and that's where all the flavour comes from - I feel as though there is no way you've missed this and therefore I've missed something here too.


So far supposition ?? I know he talks off it but is anything published yet

Plus his coffee is roasty


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## garydyke1 (Mar 9, 2011)

robashton said:


> [MENTION][/MENTION]
> 
> But they're not - that's the latest thing from Perger or whatever, there are actually way more fines and they're absolutely tiny tiny and that's where all the flavour comes from - I feel as though there is no way you've missed this and therefore I've missed something here too.


x = fines

X = rocks

Robur :

[-x------------X--]

EK :

[-x----------X--]

small x is nearer large X with the EK


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## robashton (May 9, 2015)

My understanding is that there are way more fines so you need less time on the brew, and somehow magically without trying the EK43 and it's largely even particle distribution size means that with spro it gushes through faster (so you grind finer *and* get more fines) and these two facts work together entirely by coincidence.


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## garydyke1 (Mar 9, 2011)

robashton said:


> My understanding is that there are way more fines so you need less time on the brew, and somehow magically without trying the EK43 and it's largely even particle distribution size means that with spro it gushes through faster (so you grind finer *and* get more fines) and these two facts work together entirely by coincidence.


You are always brewing to the rocks, getting them to be tasty. With other grinders this means the 'fines' have gone way too far.

(in my head)


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## robashton (May 9, 2015)

garydyke1 said:


> You are always brewing to the rocks, getting them to be tasty. With other grinders this means the 'fines' have gone way too far.
> 
> (in my head)


Is it possible to get those fines to go too far with the EK then? And get this bitterness - I've still not managed, even when I accidentally do 90s ristretto with new beans.*

[edit]

Also I can get behind this notion even more, because the even particles, the fast flow rate, the tightening of the grind, the faster the rocks then get brewed also.

[further edit]

*note: this tastes like arse, just not "bitter" in the sense I'd expect in my experience at coffee shops when they screw up - beans maybe?


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## garydyke1 (Mar 9, 2011)

robashton said:


> Is it possible to get those fines to go too far with the EK then? And get this bitterness - I've still not managed, even when I accidentally do 90s ristretto with new beans.
> 
> [edit]
> 
> Also I can get behind this notion even more, because the even particles, the fast flow rate, the tightening of the grind, the faster the rocks then get brewed also.


Espresso wise - there is definitely an interaction between fines and rocks in terms of flow rates. Perhaps the actual shape of the particles is somehow different too (in the same way conics v flats )

I note you use beans which are not 'murdered' unlike Perger







Any references to bitterness in his blogs I take with a pinch of salt


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## robashton (May 9, 2015)

garydyke1 said:


> I note you use beans which are not 'murdered' unlike Perger
> 
> 
> 
> ...


Yeah... getting this feeling.

With some of my local beans it was impossible *not* to get bitter/roasty/nasty flavours, presumably because it's hard to do a low EY with the EK.

I feel as though I need to get a cheap Mazzer and spend some time with it to learn a bit more about the "how the other side does it"


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## garydyke1 (Mar 9, 2011)

robashton said:


> Is it possible to get those fines to go too far with the EK then? And get this bitterness - I've still not managed, even when I accidentally do 90s ristretto with new beans.*
> 
> [edit]
> 
> ...


I would like to see the particle distribution info for the EK new coffee burrs, only ever seen old


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## garydyke1 (Mar 9, 2011)

robashton said:


> I feel as though I need to get a cheap Mazzer and spend some time with it to learn a bit more about the "how the other side does it"


I rarely enjoy traditional espresso from the other side


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## robashton (May 9, 2015)

garydyke1 said:


> I rarely enjoy traditional espresso from the other side


I don't think I do either - you get used to it after a while (the first few months after moving to Glasgow were hell), there are a couple of Mythos places now (one which uses Has Bean and does a reasonable job of it), and one which uses their own roast and keeps it short - presumably to avoid those roasty flavours that I can't avoid.

This was by and large a big reason for me deciding to learn how to do coffee myself - which is why I've got "all the gear and no idea, and a ton of stupid questions"


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## MWJB (Feb 28, 2012)

robashton said:


> I mean - a whole bean has a total soluble content of 24-36%, the grinder does not change this - right? Unless we are saying that by bashing up the beans into tinier pieces we expose more of this soluble content and that with bigger bits of bean it's just impossible to dissolve it as fully - even with "infinite" time.


OK, yes you're right, the grinder doesn't change the amount of soluble matter available.

With percolation the variance in grind size is a limiting factor because as we actively wash out the grinds, very large grinds will have their exterior completely scrubbed of soluble matter, whilst the inner layer may be extracted ideally, but the very core may be underextracted...whichever of these defects is having the bigger effect limits the overall tasty %EY in the cup. Pushing enough water through to scrub the very last/or last good bit of soluble material from the larger grinds will normally mean you have already taken too much from the outer layers...& probably the majority of the target sized grinds too. This would be a weak & bitter drink.

Maybe when you were a kid you sucked on an ice lolly until part of it had no colour & flavour left, the rest looked untouched? Uneven lolly extraction. By the time you sucked all the colour out you'd also have taken out a fair degree of water but still probably given up (brainfeeze!) with some colour left in the lolly & some ice on the stick that you threw away? This is where your 19%, 21%, 23% etc. extractions become important targets to hit the peak of sweetness.

In immersion, the process is much gentler...ultimately, at a reasonable brew ratio, it's extremely difficult to overextract without maintaining applied heat. Infinite time doesn't matter so much, unlike infinite water/time in percolation, because there's no rinsing washing. Your full water weight & coffee are in contact for the majority of the brew time & you're waiting for the concentration to even out & reach equilibrium...which it will normally do at a lower TDS than drip (EY's are calculated a little differently between drip & immersion, 20% drip at 60g/l is ~1.3%TDS, but for immersion it's ~1.14%). For immersion you don't need a super consistent grind to hit say 23-25%EY, you just need to be generally fine enough & leave enough time & heat...almost any grinder, hand or electric, mentioned on these forums will achieve this.

Immersion - Let's say you put your ice lolly in a cup of water & just let the whole lot melt? Much less physical effort, more time & the colour, flavour, lolly material & water end up evenly distributed in the liquid in the cup at the end (only fault with this analogy is that we can't distinguish between the water the lolly was made with & the additional water we put in the cup, easier if you think about this example as a cupping/Turkish without separating grounds from beverage?). You might still hit good flavours at lower targets too, but a lot more coffees & grind profiles will also taste good at 23% plus...unlike with percolation.


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## robashton (May 9, 2015)

Okay - I think I follow that and can reconcile it with my experience so far.

Essentially because with the EK the good bits are easily extracted because we're at a fine even grind, we reach our target TDS more easily and extract far less of the undesirable matter.

Because with a super long immersion brew we've got a decreasing temperature, once we've extracted what we're going to extract we're unlikely to extract those undesirable bits.

==

It is likely that in my 30 minute aeropress that I reached target TDS at 10, 15 or 20 minutes into the brew and the extra minutes did very little to add onto it. (I can say that the difference between 3-5 was noticeable which is why I ended up giving up and soaking until I got bored)

[edit]

I see you have a blog, I'll go through it and see if there is anything I can add to what I've already read from Perger/Prufrock/Maxwell (!!)


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## Xpenno (Nov 12, 2012)

Mrboots2u said:


> So far supposition ?? I know he talks off it but is anything published yet
> 
> Plus his coffee is roasty


I've seen the graphs


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## jeebsy (May 5, 2013)

Where else has an M1 now? Didn't see one in Avenue at the weekend


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## Xpenno (Nov 12, 2012)

I gave sine theories, probably bs.

Ek has more fines and grinds more evenly than most other grinders I.e. the larger particles are differ less from each other and also from the mean particle size.

For immersion brews the water can easily soak into all coffee particles and dissolve solutes less aggressively but more evenly so grind evenness matters slightly less imho.

In pour over and even more so in espresso the water passes over a particle in a given amount if time and is pushed or dragged away by either pressure or gravity. The larger particles are therefore less likely to extract evenly and the bigger they are the more this is true. They will extract more (over) on the surface and less in the centre.

Any extractions is a balance to flavours.

With the ek you end up with sweetness from lots of fines and not so much bitterness as the rest if three grinds are comparatively similar to the fines in the first place so the extract more evenly as the total surface area is greater.

With a robur you get less fines and more larger particles which extract unevenly I.e. the surface over extracts and the middle is relatively under extracted, hence more bitterness. This is amplified by the fact that there is less sweetness from the evenly extracted fines as there are less of them. As you push the extraction everything starts to over extract as the overall surface area is small in comparison to the ek brew.

(Waits to get shot down......)


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## robashton (May 9, 2015)

jeebsy said:


> Where else has an M1 now? Didn't see one in Avenue at the weekend


Papercup, at least I thought I saw one up the bar


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## jeebsy (May 5, 2013)

robashton said:


> Papercup, at least I thought I saw one up the bar


Didn't notice it when i was in last week but wasn't paying much attention


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## funinacup (Aug 30, 2010)

Believe they had the demo model on the bar.


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