Thanks.
I certainly think it's my grinder/burrs is a factor. And perhaps using beans that are too fresh.
I bought the K3 new and estimate that over the past 8 or so years ran somewhere between 100-130kgs through it. I didn't think the burrs were worn but changed them anyway.
I have now ran around 3kg through the new burrs and have noticed a change in grind (much less clumping). This is also a reason why I haven't changed technique recently, I was trying to demonstrate whether the burrs are breaking in and whether this is a factor
I'll continue testing... Thanks guys!
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Ah I completely forgot, I started a thread a few years ago about my K3 and inconsistent shots, feel free to read it! Although I can summarise the end, got new burrs, still getting inconsistent shots for a bit, but then eventually they completely settled
I have had my fair share of grinder issues over the years so can understand the frustration...
Thread here if interested:
https://coffeesnobs.com.au/forum/equ...ly-burr-change
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Ah apologies, didn't realise you'd be using that same setup and technique for all those years. Yeah it's a bit of a headscratcher... I do remember with my K3 I did start getting inconsistent shots and I got new burrs eventually to see if that would sort it, after a bit of running in the shots eventually did settle (I think I bought a kilo of low quality beans to grind through too). See how the new burrs go after settling. Could be a machine issue but not too sure... you mentioned you bought a new machine recently so that wouldn't make much sense though... good luck!Originally posted by Kit666 View PostPerhaps I should clarify. I've been troubleshooting inconsistent extractions for over a year. I did not experience this level of inconsistency over the previous 8 years of me using that particular setup. Over the course of the year (which coincided with covid and spending much more time at home) I've tried changing numerous aspects of my technique with little success. I've introduced weighing dose, weighing extractions, and adding a distributor tool (amongst other things... eBay loves me right now). I've also been spending a lot of time ensuring good and consistent technique to minimise error on my part. This all culminated in me changing machines and grinder burrs early this year. So I certainly have been trying different things. The minimal change in technique after starting a log is to methodically build a data set before changing one single aspect and then building another dataset. While I take your point that I should try hopper dosing, I have been single dosing the previous 8 years. But yes, I'm a little out of ideas at this point in time so I'm looking to try that as the next thing to change and log. Thanks for the suggestion!
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Perhaps I should clarify.
I've been troubleshooting inconsistent extractions for over a year.
I did not experience this level of inconsistency over the previous 8 years of me using that particular setup.
Over the course of the year (which coincided with covid and spending much more time at home) I've tried changing numerous aspects of my technique with little success. I've introduced weighing dose, weighing extractions, and adding a distributor tool (amongst other things... eBay loves me right now).
I've also been spending a lot of time ensuring good and consistent technique to minimise error on my part.
This all culminated in me changing machines and grinder burrs early this year.
So I certainly have been trying different things.
The minimal change in technique after starting a log is to methodically build a data set before changing one single aspect and then building another dataset.
While I take your point that I should try hopper dosing, I have been single dosing the previous 8 years. But yes, I'm a little out of ideas at this point in time so I'm looking to try that as the next thing to change and log. Thanks for the suggestion!
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Was literally just about to say what emslibbles said! Definitely try hopper dosing. Most grinders are designed for this use, but many insist on single dosing. It certainly can work for some grinders and not be an issue (especially ones designed specifically for it), but really hopper dosing I think will get you much more consistency.
And you do not have to leave the beans in the hopper all the time, not at all
. After you've finished making coffees, you can easily close the hopper gate and pour the beans back in their bag. And it's easy enough to get the leftover beans in the throat of the grinder out too, I had/still have a K3 and it was an easy process.
There is a reason why it extracts faster when single dosing compared to hopper dosing on the same grind setting, it's certainly not grinding the beans the same so to speak. When I switched to hopper dosing my consistency was night and day different. Hoping that's the issue here, but see how you go
Ps. Oh and make sure you weigh the actual dose that's in the basket, rather than assume it's the correct weight because the grinder was grinding for the same time period
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Yeah, look... i’ve tried nothing and I’m all out of ideas!
Maybe its worth filling your hopper. I find some grinders can be really inconsistent if they don’t have some downward pressure. For the sake of science, just run with beans in the hopper for a few days?
Yes, your beans will age over the test a bit faster than if they’re airtight, but at least you’re checking another variable of the list!
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Thanks guys.
I also initially thought ambient temperature and humidity was affecting the extraction. But now I'm not so sure.
While I don't have a single dose grinder, I always single dose (beans never sit in my hopper), so from that perspective, even though I know it's not optimal, it is consistently not optimal
I'm seeing large variances intra day and sometimes shot to shot (less so shot to shot), so that rules out bean freshness
My technique is always the same:
- grind into basket
- tap PF on the bench top to settle and distribute grinds
- use distribution tool
- tamp very carefully
based on the commentary above, there's definitely something wrong on my end... I just don't know what!
Here's a sample of the log from the past two days to demonstrate what I'm referring to above
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Is it possible that the time spent in the hopper affects the outcome (e.g. fresh from bag vs several days sitting in the hopper)?
Is it possible that the level of beans in the hopper affects grind size or consistency?
Java "Yes to both questions" phile
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In case it helps, I tracked similar data for a period; several rows from that table follow.Originally posted by Kit666 View PostAre most people seeing similar results? Or are most people getting much better consistency in their extractions?
This is with a single dosing grinder, so I can switch beans at will. During the period shown above I was doing some experiments on dose while keeping grind constant.
Is it possible that the time spent in the hopper affects the outcome (e.g. fresh from bag vs several days sitting in the hopper)?
Is it possible that the level of beans in the hopper affects grind size or consistency?
I also note that in your table, shot times seem to be weakly correlated with ambient temperature - that is, cooler temperature ~= longer shot times.
Brett
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Have you tried putting a humidifier next to your grinder? Those early humid days were so consistent! 😂😅
I can’t remember, are you using any distribution techniques?
I wouldn’t have that much variance. Over the course of a work-week, I’d say only 1 of the 20 shots would vary by more than a couple of seconds.
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Thanks maltur, this is certainly an option to consider, however, I would much prefer to fix the cause rather than alleviate the symptom.Originally posted by maltur View PostHere's another idea to throw out there... have you thought about trying to turn you brew pressure down? Maybe to 7-8 bars instead of 9-10 bars? I understand 9ish bars is the recommended; but if the grind/puck prep isnt perfect; reducing the brew pressure may reduce the channeling. It would be a tradeoff of course; consistent good shots vs the occasional perfect one.
this is also the reason why I went back to the VST basket after seeing some success with the OEM.
The way I see it, there is either a problem with my technique or my equipment, and I really want to fix it there (at this I'm leaning towards equipment as I've been so careful to eliminate potential technique variances).
I've attached a portion of my log.. technique and grind setting is the same throughout this period.
You can see some consistency but then an occasional outlier that's totally off.
Are most people seeing similar results? Or are most people getting much better consistency in their extractions?
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Here's another idea to throw out there... have you thought about trying to turn you brew pressure down? Maybe to 7-8 bars instead of 9-10 bars? I understand 9ish bars is the recommended; but if the grind/puck prep isnt perfect; reducing the brew pressure may reduce the channeling. It would be a tradeoff of course; consistent good shots vs the occasional perfect one.
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Freshness as a variable is a hard one, unless you’re quite familiar with the beans and their roast. Some need 5 days, some 10, some 20! Due to Canberra roasters only typically selling 200 or 1kg bags, i often use rather gassy beans at the start. In my experience does have an impact on other things, but not channeling or shot-shot consistency specifically. At least not to the values you’re suffering!
My experience is that different machines with different factors like head space can significantly impact the likelihood of channeling too... on my Breville Dual Boiler i use to sometimes dose up to 24g in my 20g VST with great consistency, but on my Profitec Pro 600 I can’t go much over the rating without causing fluctuating channeling (all else being equal). So i now use 22g in a 22g VST most of the time.
Another factor, i started using a dosing cup rather than grinding straight into my portafilter (for cleaning and ease of weighing purposes...) and that also decreased instances of channeling.
Continued luck!
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Just an update...
It's been a number of weeks now, and Ive chopped and changed technique, equipment, beans etc etc etc...
I dont think I'm closer to achieving consistency and a good looking extraction that didn't have some channelling when viewed from the naked filter.
I've found that the OEM basket did give some better consistency but it still would vary more than I liked... I've since gone back to my 7 year old VST.
I got a batch of beans that although were over 2 weeks old would be super gassy and extractions would just fluctuate on a daily basis.
Then I encountered this video:
https://youtu.be/6TMkDe1XtIM
An interesting finding is that fresh beans (less than two weeks old) would have wildly varying extractions as they de gassed. Even to the point of significant differences intra day. Interesting!!!
I always thought fresh beans didn't have a developed flavour, I never considered it could result in wildly fluctuating extraction times.
with the number of boutique roasters now roasting to order, this could potentially explain a lot in my situation...
Anyway I've since started overdosing (19gm in an 18gm) basket... So far after 3 days have had some very consistent shots...
The testing continues...
Maybe bean freshness (i.e. they were too fresh) has been my problem all along... ?
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I think the answer is.... It depends!Originally posted by biffel View Post
I have often wondered exactly this point, and whether it boils down to the following question: Is the longest possible extraction time for any grind size/bean/freshness/temperature combination actually the target for perfection (in preparation) at those settings?
Brett
I've often found my longer extractions still had some visible channeling and spritzing.. which means.. it's still sub optimal!
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