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Problem with shot extraction


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Hi there

hoping for some advice with a recent issue I’ve been having. Only since changing to particular bean (crown and canvas, natural Rwanda) 

shot starts off the same for what has always been normal for me but then the base of the portafilter becomes very sparse with liquid that seems to congregate at certain areas only. It appears to have reduced flow but when I time my shots it’s in fact pouring out quickly. 
typically I dose 18g in to 38g out in about 30 seconds (+/-2s)

this particular shot was definitely running quick at 45 grams in only 24 seconds but even when I’m hitting my desired ratios in the expected time the extraction looks the same. 
 

is this an issue with grind size?? I have gone coarser thinking it might have been too fine and causing channeling but same issue

ive also noticed that my pressure is hitting about 11bar which is new although I can’t tell if it has only been occurring since this bean issue or not. Could the high pressure be causing channeling?  
hopefully the video will attach 

https://youtu.be/Y5OSgT1moG8

thanks for any help

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Apologies, the video continues for a couple minutes. I hadn’t realised it was still recording. Only the fist 30ish seconds are of the shot 

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Video set to private?

How can it be coming out quickly if you get 1:2.1 in 30s?

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Assuming there is no problem with the machine and your dose isn't too high or low etc....

Don't worry about how the shot looks. If you've worked on distribution and your shots usually look good it's probably not an issue. Judge based on how it tastes. Don't change things unless you taste it and think the extraction needs to be improved (presumably judging by the flavour notes on the bag if you usually get them from this roaster). 

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2 hours ago, MWJB said:

Video set to private?

How can it be coming out quickly if you get 1:2.1 in 30s?

Sorry, no longer set to private. So this particular shot definitely ran fast as was a 45g in 24 seconds

2 hours ago, Rob1 said:

Assuming there is no problem with the machine and your dose isn't too high or low etc....

Don't worry about how the shot looks. If you've worked on distribution and your shots usually look good it's probably not an issue. Judge based on how it tastes. Don't change things unless you taste it and think the extraction needs to be improved (presumably judging by the flavour notes on the bag if you usually get them from this roaster). 

so I feel it was sour but I do struggle to tell the difference between sour and bitter coffee (?)

I think it’s about 10 -12 days from roast so presumably degassed enough

ill try a different bean to see if I’m still getting 11 bar pressure to see if that is an issue with the machine

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21 minutes ago, RobDGio said:

Sorry, no longer set to private. So this particular shot definitely ran fast as was a 45g in 24 seconds

Sorry, you said that the shots still looked the same at your desired ratio & time? I wouldn't expect a big change in the look of the shot.

I'd either go finer and/or pull more weight of shot out.

 

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You can turn the pressure down a bit by altering the opv. 

If you can't tell the difference, I'd assume sourness and push the ratio higher and/or grind finer. 

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thanks for the input.  I had thought about turning down the OPV but I know when I first got it back in January that it definitely was hitting 9 Bar.  Im just not sure how recently it has also been hitting 11Bar and whether it has something to do with failing to dial in this particular bean or unrelated.  

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Hoping to pick people's brains a bit more on this.  When doing a backflush I was hitting bang on 9 bar (so have left the OPV alone),so in respect to hitting about 11-12 when pulling shots with this new bean I'm presuming I have ground too fine.  I did tighten the grind a bit more as suggested given the shot running fast (eureka specialita, from 1 on the dial to about 0.75, my zero point being about -1) but this had little affect if any and shot still ran fast.  Am I right in thinking that i may be creating lots of channeling given how fine the grind is and thats why its running fast or should I keep grinding finer as it would be more likely to choke if grinds were too fine.  only thing is the puck looks normal, maybe a little excess water on top compared to normal so didnt appear to be channeling, maybe??. Not really had issues dialing in before but this bean seems to be throwing me a curve ball! 

Only been doing espresso since January so still pretty new and so far things have gone fairly smoothly so not had to try problem solve much. bit stumped with this one though

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1 hour ago, RobDGio said:

but this had little affect if any and shot still ran fast. 

Sorry, can you quantify what you mean exactly by "running fast"? It will have more context if you tell us the ratio & time you ran the pump for.

Also bear in mind, you're not aiming for a time, you're aiming for a pleasing result in terms of taste, this can happen at a range of times, so describing the fault you can taste is most useful. If you have trouble identifying what the fault is, try making the shots a little weaker (longer ratio) to reduce intensity & see if they open up in terms of flavour attributes.

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just a (very newbie)  2p

but from what I've read, are these 'blank' spots on the shower head a sign of channeling - hence the high flow rate..?

1967341334_Screenshot2021-06-03100920.jpg.c82260927b763e0c1639f9d5df71248a.jpg

 

 

..regards...................john...:coffee:

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3 minutes ago, yardbent said:

just a (very newbie)  2p

but from what I've read, are these 'blank' spots on the shower head a sign of channeling - hence the high flow rate..?

1967341334_Screenshot2021-06-03100920.jpg.c82260927b763e0c1639f9d5df71248a.jpg

 

 

Well, that’s my query. As I am much finer than normal with this bean but hitting a near 3:1 ratio in under 30 seconds when typically I’d dial in a shot with what tastes good to me at a 2:1 ratio usually around the 28-32 second mark

@MWJB by “running fast” I mean that I was hitting desired output weight of 38 grams in close to 20 seconds and it was on watching what the bottomless portafilter looked like, with the “thin” looking flow in the above picture, with very sporadic patches of flow that something seems wrong compared to normal. Coupled with the 11-12bar pressure I’m getting I’m just confused where I need to go. Taste wise I’d say sour (so grind finer?) which seems to be supported by how quickly the shot is flowing but then why such a high pressure? 


have I ended up grinding too fine by mistake which is causing channeling leading to under extraction, hence the flavour but because there is so much channeling the output flows so quick?? 
sorry for the long post and hope all this is making sense. Really appreciate people taking the time to help and advise 

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33 minutes ago, RobDGio said:

have I ended up grinding too fine by mistake which is causing channeling leading to under extraction, hence the flavour but because there is so much channeling the output flows so quick?? 
sorry for the long post and hope all this is making sense. Really appreciate people taking the time to help and advise 

Firstly, I'd say for a light roast, pull a bit more weight out. Try 1:4. If it takes 20s to get 38g out, how long does it take to get 72g?

I hope this doesn't sound evasive, or akin to 'follow your nose', but let's say you are right & you have ground too fine - keep going coarser until shots are bizarrely quick, or all totally sour.

But looking at the video you posted, the stream seems pretty pale & ragged right from the off, I can't help my gut feeling that for a 1:2 shot you should probably be finer. 

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Thank you.  I'll try 72g output and see what that's like first to see what i get then try going finer as you have suggested for a 1:2 ratio. Hopefully this sheds some light and I'll report back

Thanks again

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I ended up just tightening the grind a bit finer. Seemed to resolve the sourness issue and surprisingly pressure settled at 9bar as opposed to jumping up to near 12. No idea why that’s happened but glad it has resolved. Also shot “looked” better although I appreciate people saying that’s not the best indication of anything. 
thanks again

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