# Extraction problems... What's going on!!



## shrink (Nov 12, 2012)

So long story this one, but cutting it short, I'm getting pretty much nothing but bitter tasting shots that leave a rather dry feeling in the top of the mouth.

If I grind coarse, it just pours through the machine in about 15 seconds and tastes thin, sour and weak.

If I tighten the grind, two things happen. Firstly the time delay to initial pour becomes around ten seconds with blonding kicking in at about 25 seconds, meaning only 15 seconds of useful pour. Coffee still tastes too bitter.

If I tighten up any more, I get drips at around 15 seconds, and then end up with a 37 second ristretto that is acidic and sharp.

I've had a real nightmare getting my grind consistent at all lately and my mc2 had a small freak out a while back, and I wonder if the grinder is just screwed and producing completely inconsistent grinds that are causing serious channeling and resulting in both over and under extraction.

Tried various flush times, and temperature does not appear to be the issue, shots taste almost the same no matter how how hot or cold the machine is.

Could the cherub be putting too much pressure through the puck? Meaning that its overpowering coarser grinds, and just forcing its way through tighter grinds.

Or do I just need a much better grinder. I'm close to pulling my hair out at his stage. I was getting much much better coffee than this not long ago.


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## fatboyslim (Sep 29, 2011)

Has anything changed since then? Have you removed shower screen and dispersion block for a good clean? Could be your grinder? Give that a good clean.

Clean everything you can think of. Are the beans super fresh? Did you change baskets? Do you still get the same issues with the stock Fracino basket?

Sorry to hear about these troubles.

If it makes you feel any better my brother's girlfriend lost my shower screen screw down the sink so I am unable to make espressos at the moment.

Screw costs 36p but still the standard £10 from Fracino. £10 for one frickin' screw!!!


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## MWJB (Feb 28, 2012)

"If I grind coarse, it just pours through the machine in about 15 seconds and tastes thin, sour and weak."

OK, this is clearly underexracting. So you do need to go finer.

"If I tighten the grind, two things happen. Firstly the time delay to initial pour becomes around ten seconds with blonding kicking in at about 25 seconds, meaning only 15 seconds of useful pour. Coffee still tastes too bitter."

I'd guess that this is still under, "bitterness" can be present in under shots...I'd suggest letting this run on so you get at least 20 seconds of pour through the puck?

"If I tighten up any more, I get drips at around 15 seconds, and then end up with a 37 second ristretto that is acidic and sharp." Again, this suggests under...let it run on, if it's literally dripping out, stick your finger in the stream and dipstick test the output until it goes thin & bitter, then pull the cup away.

You don't mention any output weights, what sort of brew ratios are you aiming for?


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## shrink (Nov 12, 2012)

I clean the machine regularly, and had everything off, and back flushed thoroughly.

The grinder had a packet of grinder crystals run through it recently, and has had two packs of beans through it since then. I'm on my hard bag of allpress redchurch, a coffee that I know can taste amazing if brewed properly. I've had good shots from it at home.

All I can think of is that the grinder freaked out during my training session, made an odd noise and turned very slowly. Since then it "look" ok and seems to grind the same as it always did, but even a small variation could be causing very uneven grind I guess?


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## shrink (Nov 12, 2012)

MWJB said:


> "If I grind coarse, it just pours through the machine in about 15 seconds and tastes thin, sour and weak."
> 
> OK, this is clearly underexracting. So you do need to go finer.
> 
> ...


I I let it run on past 25 seconds in the shot with the 10 second delay... It's just watery stuff that's coming out. The nice part of the pour only happens between the 10 second and 22 second mark. I'd also end up with way too inch liquid if I let it carry on. Seems the puck reaches a breaking point and just pisses liquid.

I've never really done the weight thing. I always managed to get on just fine by weighing the beans going into the machine, and aiming for a set time, while keeping an eye out for blonding. But even with same weight going in, and same tamp and same time, I find I'm getting very varied shot results.

Leading me to suspect the grind is poor


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## The Systemic Kid (Nov 23, 2012)

shrink said:


> I've had a real nightmare getting my grind consistent at all lately and my mc2 had a small freak out a while back, and I wonder if the grinder is just screwed and producing completely inconsistent grinds that are causing serious channeling and resulting in both over and under extraction.


What was the freak out? Are the burrs OK? As you are familiar with the beans and their characteristics, doesn't appear that they are the problem. Do you know anyone who has a decent grinder you could benchmark against? It's a right pain when your set up goes t**s up.


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## shrink (Nov 12, 2012)

Yah. I tell ya it's been bad enough to make me consider selling up and sticking with tea









I may need to see about borrowing a grinder


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## MWJB (Feb 28, 2012)

Scenario #2 then does sound like you're going over. Pull the shot shorter and/or go a little coarser.


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## RisingPower (Dec 27, 2009)

shrink said:


> *The grinder had a packet of grinder crystals run through it recently*, and has had two packs of beans through it since then. I'm on my hard bag of allpress redchurch, a coffee that I know can taste amazing if brewed properly. I've had good shots from it at home.
> 
> All I can think of is that the grinder freaked out during my training session, made an odd noise and turned very slowly. Since then it "look" ok and seems to grind the same as it always did, but even a small variation could be causing very uneven grind I guess?


You've looked inside right and given the burrs a clean by hand? Wouldn't personally want anything but coffee going through the burrs myself.


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## shrink (Nov 12, 2012)

Yah I even hoovered the burrs out and let it run while hoovering until it was clean as a whistle in there.


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## RisingPower (Dec 27, 2009)

shrink said:


> Yah I even hoovered the burrs out and let it run while hoovering until it was clean as a whistle in there.


My point was, maybe a little too clean?

I do wonder whether if it were something like grindz you may have removed any coffee oil residue on the burrs and left some cack on the burrs which is coming off still?

Maybe take the burrs out, give them a rinse and wipe the burr chamber with a damp cloth?

I'm just a little skeptic of putting anything but coffee and water inside a grinder, could well just be being paranoid.


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## shrink (Nov 12, 2012)

Maybe.. But with over a kilo of beans having gone through since, I can't imagine it's that. I've cleaned the grinder in this manner before.


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## RisingPower (Dec 27, 2009)

shrink said:


> Maybe.. But with over a kilo of beans having gone through since, I can't imagine it's that. I've cleaned the grinder in this manner before.


Ah, fair does. Burrs look fine otherwise then?


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## shrink (Nov 12, 2012)

Well... To my desperately untrained eye yes









The grinder is only 4 months old!


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## radish (Nov 20, 2011)

Perhaps it's a burr alignment problem?


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## MWJB (Feb 28, 2012)

Let's pause a moment, what is the single, continual, repeatable issue that points to a grinder problem? I'm not saying it isn't the grinder for sure, and if this is justification for an upgrade, you're going to do it anyway (I was on an amplifier forum the other day and some wag suggested that if a thread goes on long enough, a new output transformer will be eventually mooted as the "cure" for any issue...in much the same fashion a new grinder is often suggested here).

It strikes me that the initial concerns relate to shots that are over/under at a certain shot time...not all under, not all over. The grinder is almost choking the machine in scenario 3, too coarse in scenario 1...possibly a shade fine in scenario 2 (giving up the goodness before the usual output is achieved)?

You talk about a pause time, if you're using a forked portafilter (rather than naked), we don't really know how much of that time is really a pause, you could be getting a thick, gloopy output that is sitting on the fork for a moment before being washed down, giving the impression of a slightly longer pause, shorter flow through the puck?


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## shrink (Nov 12, 2012)

It is indeed a split portafilter. My naked doesn't take the larger vst basket I'm using.

I could easily enough pick up a new one though.

My concern is that at a fineness that allows a shot to get anywhere near 25 seconds, it results in a very large apparent pause time. To grind any finer would seem potentially unwise. I had considered grinding finer and just tamping less, allowing the natural resistance of the coffee to control the timing.

My worry was that the iberital, which seems to create slightly clumpy and potentially uneven grind, is causing rather unpredictable extraction, with some parts getting over extracted and some under, with water eventually just pouring through areas f weakness.

Certainly if I watch the pour, there are inconsistencies in delivery, varying from thick and dark to light, and back to dark in the same stream, would seem to suggest some kind of weird extraction,

I do try WDT, dispensing into portafilter, moving it around with a toothpick, and then sweeping the top flat befre tamping. But it seems to make little difference.


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## fatboyslim (Sep 29, 2011)

Which VST baskets are you using and what doses are you using? I have to use 14g in 15g VST and 16.5g in 18g VST.

Make sure there is no impression on the puck from the shower screen. This would definitely mess your shots up!


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## 4085 (Nov 23, 2012)

I think it is a combination of the bean you are using, your grind and your tamp. I have been roasting the same Nicoraguan bean for a couple of weeks now. Same roast, same profile, yet the packet I opened yesterday required me to set the grinder up again as if it was a totally new bean.

I would grind to the fineness you iamgine it should be, then play with your tamping.......or, try a different bean


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## shrink (Nov 12, 2012)

I tend to use 17g in a 17g LM basket, so a basket that's rated to 18-19g


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## fatboyslim (Sep 29, 2011)

Try using less?


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## Chris_on_caffeine (Jul 21, 2012)

Make us a lovely video to see what's what


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## garydyke1 (Mar 9, 2011)

There isnt 'coarse' and 'fine'..there are probably 20-50 settings between. The MC2 has the most tweekable grind settings due to that worm drive.

Weigh output versus input versus time and cap some parameters around this frustrating finger-in-the-air approach

This stressing isnt doing you any good!


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## shrink (Nov 12, 2012)

No and the bitter coffee isn't doing me any good either


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## shrink (Nov 12, 2012)

Much much better success today.

I found a quote from "systemic kid" which commented on never applying pressure while polishing a tamp. It occurred to me that in an attempt to get a good finish and try to be consistent lately, that I was doing just that.

Today, I made the grind a notch finer, applied a single downward tamp, and then removed all pressed before a very quick polish.

Result? A lovely, smooth, rich tasting shot. And a gorgeous flat white.

Definitely at the ristretto end, but that's how allpress recommend extracting this coffee. First pour at 11 seconds, 28 second extraction. It was yummy.

Will try to replicate tomorrow and see if I can make it more consistent.


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## The Systemic Kid (Nov 23, 2012)

Nice one Shrink. Good to hear you're back in the zone.


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## shrink (Nov 12, 2012)

It's thanks to your advice that you gave someone else mate









I made three coffees in a row, they all extracted well, with nice rat tail pours. My flat white was tasty with no hint of dry bitterness


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## coffeechap (Apr 5, 2012)

Hooooooooray


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## The Systemic Kid (Nov 23, 2012)

That's what's really good about the forum - the way members help each other out. Long may it continue!


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## shrink (Nov 12, 2012)

Absolutely.

Still want a new grinder tho


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## coffeechap (Apr 5, 2012)

When you are ready give me a shout, will hav the grind off ones available after the grind off, but the price goes p for the winner!!!


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## shrink (Nov 12, 2012)

Hehe... At the moment the biggest obstacle will be height.

I quite fancy the idea of an anfim super caimano on demand, with doser.


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## coffeechap (Apr 5, 2012)

You missed one in Edinburgh about 3 weeks ago went for stupid money on gumtree!


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## shrink (Nov 12, 2012)

I'm just not paying attention enough to these things.l. Must check gumtree more


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## coffeechap (Apr 5, 2012)

You should there seems to be some great bargains up there


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## shrink (Nov 12, 2012)

Ultimately I may need to wait till we get a new house, as at the moment, maximum height is 50cm. So to be able to get beans into it, even shorter is needed. The relatively compact anfims are ruined by their huge hoppers, which make them 57cm. So not sure I'm wise buying anything just yet!

I guess a mazzer without hopper would probably work. Not sure how well the anfims will single dose. Lots of research to be done!


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## coffeechap (Apr 5, 2012)

Wait till after the grind off as a lot of the research will be done for you and most of the big hitters will be in it. Anfim are even 58 cm to the centre of the hopper, although single dosing is dead easy on them and a micro hopper would not be tough to source.


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## shrink (Nov 12, 2012)

Also worth noting that since running out of coffee and having a few days till more arrives, I took the chance to open up the iberital and clean it out.

It was pretty nasty in there, with a LOT of compacted old coffee hanging around. Since a lot of this will have been there for the four months of ownership, I guess that could also be having a negative effect on extraction,

I look forward to trying it with fresh beans on a completely spotless grinder!

Now that I know how easy it is to take apart, I won't hesitate in doing it once a month.


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