# Bottomless shot diagnosis please!



## tj893 (Apr 17, 2020)

Hi all!

I wonder if anyone might be able to help me figure out how I can improve my shots- I've taken a video of a typical bottomless shot of recent on my Lelit Elizabeth:






You'll notice that the shot starts to "break up" after around 20 seconds - the coffee thins down and no longer flows through from all parts of the bottom of the basket. I'm not sure when this started to happen but I feel like it hasn't always been this way- I haven't been looking so closely in a while&#8230;

Key info below:

Coffee weight: 14gr

Coffee out: 28gr

Preinfusion time 10s (3s pump on, 7s wait)

Total shot time (inc preinf) 30s

Approx number 12 on the niche grinder

IMS competition basket double shot

Any help greatly appreciated!


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## DavecUK (Aug 6, 2013)

@tj893 Is that a 14g basket?


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## Rob1 (Apr 9, 2015)

If it doesn't taste like there's something wrong then don't worry about it.

Could be a number of things. Channeling as the puck erodes or basket holes getting clogged. If you're having to grind particularly fine for a light or even medium roast coffee this would be common, in my experience trying to make the shots look good out of a bottomless just makes the coffee worse in this case. The shot seems to start over one side of the basket so distribution could probably be improved but you might still see the same thing happening even if it forms perfectly. Decreasing pre-infusion time (the 7 second wait particularly) might stop this but as I said it really does depend if there's anything wrong with the shot itself.


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## tj893 (Apr 17, 2020)

Thanks both for replying.

@DavecUK According to IMS it's 14-16gr (this one IMS)

@Rob1 I'm with you on not particularly caring how it looks for aesthetics sake alone. I'm just wondering if it's a sign that the results could be improved further, particularly as I believe it wasn't happening initially (and definitely not with previous setups).

I tried the standard Lelit double basket instead of IMS but didn't see a difference.

If I grind coarser then the flow is faster and perhaps "chokes" or breaks up less, but the shot is pretty quick. Perhaps I should try increasing the amount of coffee with a coarser grind&#8230;

I notice that when coffee has literally just been opened then the shot breaks up less and seems "fuller" when flowing.


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## Rob1 (Apr 9, 2015)

tj893 said:


> Thanks both for replying.
> 
> @DavecUK According to IMS it's 14-16gr (this one IMS)
> 
> ...


 If it doesn't taste like it can be improved further it probably can't. The older the coffee gets the more you'll see this. A higher dose and a coarser grind will mean you need to use a longer ratio to get the same ey, and though the coffee might actually improve it's no guarantee and you might prefer a shorter ratio. If you don't use a longer ratio, by increasing dose and coarsening the grind you'll just be decreasing extraction.


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## DavecUK (Aug 6, 2013)

@tj893 Possibly worth trying 16g, might work better with a fuller basket.


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## MediumRoastSteam (Jul 7, 2015)

@tj893 - which grinder? Which beans?


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## tj893 (Apr 17, 2020)

@Rob1 Thanks for that- some good food for thought and I hadn't thought about the impact of increased dose on ey. Will bear that in mind and pull a longer shot as well as part of the testing. And yep there's nothing wrong with the taste of the shot as such, I guess I wondered if this was a sign of something that could be improved and better the shot. We shall see- as you say it may get worse!

@DavecUK Cheers Dave, yep I'll give that a go, maybe it will help keep the shot together for longer with or without an improvement in flavour.

@MediumRoastSteam It's a niche zero and some medium to medium-dark beans (as usual). I forget which beans specifically as it's from the dog and hat sub but I've noticed it with all beans recently.


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## MediumRoastSteam (Jul 7, 2015)

@tj893 - then we have the same setup! Niche + Elizabeth. I'll pay attention today, but I don't shots look like yours.

For reference: I use mainly light roasts (medium/light sort of thing), grind 18g into a VST 18g, WDT, thump and level tamp.

temperature is set to 93C.

Steam Pre-infusion is 3s pump run, 10s total , and my shots last approx. 35s (including pre-infusion).


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## tj893 (Apr 17, 2020)

@MediumRoastSteamahh thanks that would be great! As for puck prep:

I grind directly into the PF, I use a WDT tool like this, little tap to settle the grounds and then a "the force" tamper (Youtube) so the tamp pressure should be the same every time. Come to think of it maybe there's a chance I'm tamping too hard, I'm not sure if the shot breaking up is a symptom of that&#8230;


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## MediumRoastSteam (Jul 7, 2015)

I just checked. It's not like yours. I also use a levelling tamper - the Bravo Tamper.

Which basket do you use?


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## HVL87 (Dec 17, 2019)

I also notice this as coffee beans age. When were the beans roasted? And how do you store them?

If you were previously using the stock basket you may have noticed it less.

Out of curiosity what is the pressure reading on the manometer when pulling a shot?


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## tj893 (Apr 17, 2020)

Sorry for the delay in reply, I'm actually away so will be trying out any suggestions after the weekend.

@MediumRoastSteam Thanks for checking, it's really useful given we have the same equipment. I use an IMS double basket with 14gr (IMS) however I did go back to the stock Lelit basket and found no difference.

@HVL87 I tend to mainly use dog and hat sub 250gr beans bags so they're usually fresh and ready to use. I either keep them in their resealable bag or in an airscape.

I switched to the IMS straight away as I already had it. I guess part of me wonders if some element of the machine itself might now be causing it but that's probably unlikely. The manometer hovers around 10 bar which I understand is pretty normal. Perhaps I should run a shot either with no pf or with an empty bottomless pf to see if the water distribution changes over around 30 seconds. Although that's probably a daft thing to try.


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## MediumRoastSteam (Jul 7, 2015)

tj893 said:


> I use an IMS double basket with 14gr


 That basket will comfortably take a 16g dose, if not 17g. Have you tried the 10p coin test?

Dose 16g in the basket and tamp. Put a 10p coin on top of the puck. Lock the PF. DO NOT BREW!!!!! Unlock the PF and inspect. If there's no indentation (i.e.: it touched the shower screen, then you are good and can increase the dose). If it does touch it, decrease the dose.


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## newdent (Feb 20, 2021)

The fact that your basket is saturating over to one side during pre-infusion implies your tamp isn't level and you can see that flow is favoured on that side after pre-infusion.

Medium+ beans don't required much pre-infusion in my experience but everyone has different tastes. Looks like you've ground quite finely as it takes the full pre-infusion time to saturate the puck, though this depends on your pre-infusion pressure - what is it?

I'd try taking the pre-infusion right back to basically nothing (I assume these machines have a slow ramp up anyway?) with the aim that the puck is saturated by the time full pressure is applied and see how it tastes with that. Will mean grinding coarser.

What coffee do you make? When dialling in, I stay on the side of under extracted initially as I find that if I overextract, the bitterness can cut through milk but sourness less so. That's just me.

In my (albeit relatively limited) experience, pre-infusion is much more beneficial for lighter roasts, which require a finer grind to increase extraction. Have a play and let your taste buds guide your parameter/grind changes.


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## Rob1 (Apr 9, 2015)

The tamp is definitely level because of the tamper used. Could be the machine isn't level though...


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## newdent (Feb 20, 2021)

Rob1 said:


> The tamp is definitely level because of the tamper used. Could be the machine isn't level though...


 Oh my bad, I didn't realise the tamper sat on the basket. I don't think the machine not being level would have much effect but it can only be grind distribution or perhaps an issue with the shower screen/basket.

I sometimes find that flow can stop flowing through the entire basket near the end of a shot and the pressure starts to back off but that's on a manual machine (robot), so no idea if this machine reduces pressure near the end.


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## kahawa (Aug 2, 2021)

Do you get the same bald spots every time? Interesting to see that they too follow a flowery pattern.

Given you see better flow with newer beans, it could be linked to how coffee is ageing. If it is a blend, perhaps beans are aging differently. Make sure to store the beans properly once the bag has opened. I saw a markedly different result with same grind and workflow over a few days when i kept the beans in original bag. I have bought airscape now.

The other reason could that as shot progresses, fines migrate to the bottom of the puck, causing the clogging. If you can, try to dose up and keep/corsen the grind.

Another tip would be to minimise wdt, as you are presumably going in circles to break up the clumps, you are messing up the density of the coffee in the puck, even if you tamp level the density would be uneven. Try to just wdt top 25% of coffee to rake it level and tamp. The issue is perhaps more noticeable once beans have aged.

I bought cafelat robot as my first espresso machine and always do naked shot. And i have noticed that how you wdt, can have a massive impact on the shot so i have tried to minimise it, and ensure even distribution when i am grinding the coffee and end up with a dome in the in middle - which I rake with wdt tool to make the bed even.


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## HVL87 (Dec 17, 2019)

Even with the force tamper it can apparently lean to one side resulting in an uneven tamp. Some recommend holding the base of the tamper with one hand to keep it level whilst tamping with the other.

As Rob1 mentioned it's probably channeling as the puck erodes and better distribution may not help. I've had the same issue as you with light/medium beans and I felt like it was impacting taste in the cup. This is where flow control can be useful (not relevant to the Elizabeth unfortunately).

For me precision baskets exaggerate the "issue" visually as they have more holes covering a larger surface area. You did however mention that stock is no different.

Regarding preinfusion and puck saturation, with a VST basket vs. stock ACS Minima, for the same shot length the first drip will be a couple of seconds later but flow rate subsequently increases. You do have to grind finer with precision baskets.

Below is a reference shot with a medium roast from North Star (the docks) using an 18g VST. Even with first drip at 9-10s I don't have any issues with channeling. However a few weeks later with the same beans puck integrity is significantly lower and I'm seeing a flow similar to yours.

https://youtube.com/shorts/k6zpMU9dLlk?feature=share

Out of interest it might be worth trying a higher dose or bigger basket even if it does reduce EY, as it is a medium/dark roast. Also the default preinfusion on the Elizabeth may be sufficient for this roast level.


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## MediumRoastSteam (Jul 7, 2015)

HVL87 said:


> Even with the force tamper it can apparently lean to one side resulting in an uneven tamp


 I can see that happening, if you are extremely slapdash.

I have a Bravo tamper, similar to The Force. What I do is to use the tamper as intended, but once the tamper is in place inside the basket, I stop holding the PF handle (or just support it gently) and tamp. There's no way on this earth you can do a non-level tamp this way! If there is, you are an alien! 👍👍👍👍👍👍😂😂😂😂😂😂


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## tj893 (Apr 17, 2020)

Thanks so much everyone- genuinely useful discussion. I'll be back home soon and will reply properly, as well as post some findings after trying a larger dose/coarser grind.


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## MediumRoastSteam (Jul 7, 2015)

HVL87 said:


> Even with the force tamper it can apparently lean to one side resulting in an uneven tamp. Some recommend holding the base of the tamper with one hand to keep it level whilst tamping with the other.





MediumRoastSteam said:


> I can see that happening, if you are extremely slapdash.
> 
> I have a Bravo tamper, similar to The Force. What I do is to use the tamper as intended, but once the tamper is in place inside the basket, I stop holding the PF handle (or just support it gently) and tamp. There's no way on this earth you can do a non-level tamp this way! If there is, you are an alien! 👍👍👍👍👍👍😂😂😂😂😂😂


 I have to backtrack on myself here after experimenting a bit. The right thing to do, to be 100% sure, is to hold the levelling plate with one hand and tamp. It will be a level tamp, certainly. 100% of the time. Thanks @HVL87 for this!

if you do as per my quoted text above, you still need to be careful as the levelling plate can be pushed down more on one side and lift the other, just slightly, depending on how you apply pressure on the tamper. The key is to apply level pressure.


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## tj893 (Apr 17, 2020)

Thanks again everyone for your thoughts.

Over the last week I've experimented with various things to see what effect if any they might have:

- Larger dose (15g and 16g)
- Stock basket
- Different tamping pressure
- Different grind levels
- Different pre infusion
- Brew temp (up from 92 to 95)

No matter what I tried I still just got "thin" coffee that did not flow through all holes in the basket, especially for the second half the shot. When I opened a new bag of beans things improved dramatically as I felt they would but after a few days I could see that the tendency towards thinner coffee was perhaps underway and the shots were starting to break up slightly especially around the edges of the basket. See this video from the first shot today to see what I mean:






The only reason I used PI was with the belief that it was more forgiving of puck prep and I visualised how the PI would soak the coffee bed and allow greater consistency. But at least on this very limited and early change it seems like I get better flow without it. If this is the case I'm not sure why this is and what might be peculiar to my way of doing things (if at all).

One note - I'm using the steam pre infusion option on the Lelit (i.e. steam pressure is applied to the puck when the pump is off) and I increased the steam boiler temp to 142 deg C quite some time ago so I guess perhaps there's more pressure than usual. I don't think that would be a factor...

I will keep on with this new approach and see how it progresses!


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## MediumRoastSteam (Jul 7, 2015)

If it tasted better without pre-infusion, then that's great. Remember though, why bother with pre-infusion with the Bianca if you have the flow control valve? Just use that!

But don't judge by sight. Judge by taste.


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## ckrhodes (Feb 19, 2019)

That last shot looked great to me! Although very interesting that the lack of preinfusion resulted a shot that seemed to channel less. The shot with preinfusion looks to be about a 25 second shot, whereas the non-preinfusion looked to be 29 seconds. That's a big factor in the thinness of the first shot. With preinfusion you'll need to grind finer, as the pre-wetting of the puck allows for a faster flow of water to pass through, thus probably why it was a 25 second shot.

You're also dosing 15 - 16g. What's the weight of espresso in the cup? It doesn't look like you're aiming for 30g. If you're pulling a shot ratio larger than 1:2 I'd expect it to be thin at the end.

Like other people have stated, another reason it's thin could also be from stale beans. How are you storing them? If left open in the bag for even a couple days they'll start to stale. In my opinion they either need to be stored in something like a Fellow Atmos or an Airscape (wth my preference towards the atmos).

I think you said you are pulling a shot around 10 bars right? This is way too much - especially if you're pulling 10 bars throughout the entire shot. The way pressure profiling machines shine is how they taper off pressure towards the end of the shot as per the degradation of the coffee bed. With a straight 10 bars it'll just destroy the bed. I wouldn't ever go higher than 9 even with absolutely perfect puck prep. For a straight pressure shot (with no pressure decline towards the end) I'd recommend 8.

In terms of the first video you posted a week or so ago - the problem I see with that is not from a level tamp but from a distribution issue. If you fill the basket with coffee but one side is more sloped than the other and you go ahead and tamp that as it is it'll appear to be level but the inside won't. When I first started espresso I thought that tamping would push everything outwards and make everything level, but in the case of coffee that's not true. It compresses into itself and one side will be a lot more dense than the other side. It's almost like one side is a 14g dose and the other side is more like a 22g dose (if you're dosing 18g in this example) in which case the water will flow through the 14g side and run fast and thin. Of course this analogy is a bit exaggerated, but in coffee even the slighest density difference in the puck will be the place the water goes through the most. Decent Espresso posted a video on their YouTube channel about the "Spirograph" distribution method with a WDT tool. This technique helps to even everything out nicely. I think even coffee puck distribution is the most important factor when it comes to espresso. Whilst on the topic I think WDT is great but I still think there needs be an easier and quicker method for perfect distribution.


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## tj893 (Apr 17, 2020)

MediumRoastSteam said:


> If it tasted better without pre-infusion, then that's great. Remember though, why bother with pre-infusion with the Bianca if you have the flow control valve? Just use that!
> 
> But don't judge by sight. Judge by taste.


 Yep you're right of course - flavour and taste should be the most important factor. I feel like it's easy to get used to the results from a home coffee machine used daily without realising things aren't as good as they could be, and the PF might give some clues on improvements which really is the aim of this thread I guess.

I actually have the Lelit Elizabeth (not sure where the Bianca note came from - I may have misspoke earlier in the thread!).



ckrhodes said:


> That last shot looked great to me! Although very interesting that the lack of preinfusion resulted a shot that seemed to channel less. The shot with preinfusion looks to be about a 25 second shot, whereas the non-preinfusion looked to be 29 seconds. That's a big factor in the thinness of the first shot. With preinfusion you'll need to grind finer, as the pre-wetting of the puck allows for a faster flow of water to pass through, thus probably why it was a 25 second shot.
> 
> You're also dosing 15 - 16g. What's the weight of espresso in the cup? It doesn't look like you're aiming for 30g. If you're pulling a shot ratio larger than 1:2 I'd expect it to be thin at the end.
> 
> ...


 Thanks for this. I always aim for 1:2 so yep the videos are 30gr.

The older beans are definitely having a big effect (although I keep them in an airscape), but the thinness returning within a week of opening a bag from the freezer seemed to suggest to me something else might be going on.

The 10 bars mentioned is where the Lelit Elizabeth sits at by default when up to pressure. I think your comments are probably linked to the idea I had a Bianca.

Yep agree with all tamp thoughts and I'm aware that the distribution causes off-centre drip through despite an apparently level tamp. I do my best with this whilst still being pragmatic with time- I sit the PF under the niche in a wooden stand, grind direct in using a funnel, do WDT as per the decent espresso "spiral" technique you mention, one tap on a tamping mat and then tamp.


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## MediumRoastSteam (Jul 7, 2015)

tj893 said:


> I actually have the Lelit Elizabeth


 Ooppps! I remember now! We actually have the exact same combo! Got confused, sorry!

On your pre-infusion shot, it feels to me you are grinding too coarse. The first drips should appear as the pre-infusion finishes.

Where abouts are you? I'm intrigued because, we have the same setup (I think you have a levelling tamper too right?) yet my extractions don't look like yours.


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## ckrhodes (Feb 19, 2019)

@tj893

The distribution on the last video you attached looked perfect - so the first video was probably a fluke. I think distribution can be all over the place at times and it annoys me when making two espressos (for me and someone else) with the first shot coming out in 28 seconds and the second coming out in 23. I like to serve the drinks at the same time so I question whether to just drink the 23 second shot, give the bad one to the other person or make another shot and let the first one go cold...

I'm not familar with the Lelit Elizabeth so when you say it lands at 10 bars at default what do you mean exactly? To me it sounds like you're pulling the shot at 10 bars of pressure. On the Elizabeth I'm sure you'd be able to change the pump pressure? I'm more favourable towards 8 as it's gentler on the puck and doesn't degrade it as much.

Is this thinness the case with every bean? Or is this just with a specifc bean? Correct me if I'm wrong but I believe darker roasts will thin quicker than lights.

How are you freezing them? Are you seeing a difference from completely fresh? Also are you ageing the beans 1-2 weeks from the roast date? For example, if they're one day from roast and you vaccuum seal them and freeze them, the CO2 relased from the bean may be having an effect when they're packed together chilling in the freezer.


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## HVL87 (Dec 17, 2019)

10 bar at the pump will be 9 bar at the group which is the typical set up.



ckrhodes said:


> Correct me if I'm wrong but I believe darker roasts will thin quicker than lights.


 Even though darker roasts have less density the puck integrity is surprisingly better than lighter roasts.

@tj893 Whilst I don't have control of preinfusion at the moment on my ACS Minima (until I get flow control), the 6-8s ramp up seems to do the trick aiming for a total 27-30s shot with medium/dark roasts. If you replicate the no PI shot it should hopefully look and taste the same.

It seems like you're on top of distribution with the WDT tool you linked and method.


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## Rob1 (Apr 9, 2015)

tj893 said:


> The only reason I used PI was with the belief that it was more forgiving of puck prep and I visualised how the PI would soak the coffee bed and allow greater consistency. But at least on this very limited and early change it seems like I get better flow without it. If this is the case I'm not sure why this is and what might be peculiar to my way of doing things (if at all).
> 
> One note - I'm using the steam pre infusion option on the Lelit (i.e. steam pressure is applied to the puck when the pump is off) and I increased the steam boiler temp to 142 deg C quite some time ago so I guess perhaps there's more pressure than usual. I don't think that would be a factor...
> 
> I will keep on with this new approach and see how it progresses!


 Ahem.....



Rob1 said:


> If it doesn't taste like there's something wrong then don't worry about it.....
> 
> Decreasing pre-infusion time (the 7 second wait particularly) might stop this but as I said it really does depend if there's anything wrong with the shot itself.


 If you've improved the taste, great, if not then keep doing what you were doing before....I can't remember how you're using the machine and I'm not familiar with how it works to be honest. If you all head space to fill and some pressure to build (e.g. <2bar) the entire shot might hold together better. It sounds like you're running the pump for a couple of seconds (not enough to fill headspace?) and letting it sit for 7 seconds. I also agree with mediumroaststeam that the grind looks way too coarse based on how quickly the basket beads.



ckrhodes said:


> Is this thinness the case with every bean? Or is this just with a specifc bean? Correct me if I'm wrong but I believe darker roasts will thin quicker than lights.


 It's the other way around.


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## tj893 (Apr 17, 2020)

MediumRoastSteam said:


> Ooppps! I remember now! We actually have the exact same combo! Got confused, sorry!
> 
> On your pre-infusion shot, it feels to me you are grinding too coarse. The first drips should appear as the pre-infusion finishes.
> 
> Where abouts are you? I'm intrigued because, we have the same setup (I think you have a levelling tamper too right?) yet my extractions don't look like yours.


 No problem! Yes I'm intrigued also and I must admit I wonder if there are any machine issues that might be behind it (but no idea if that's the case). And yes I use a levelling and consistent force tamper. I'm in London/Kent.

I did another shot earlier and handheld the pf whilst the niche was grinding, moving my hand around to try and distribute more evenly as the grinds fell into the basket. After this the puck prep was as normal. Surprising results- I was expecting maybe an impact on just how even the distribution was, but:

- the shot ran slower

- the strange "flower" pattern as someone else put it earlier in the thread was much more obvious

I don't think I've previously quite realised how consistent the flow pattern is when the shot doesn't run well. It is not just a random channelling or thinning of the flow. I don't know what would cause this- I'm just using the stock screen and everything is clean.





[/QUOTE]

From what I've seen around the internet it seems the Elizabeth manometer usually shows 10 bar during the shot, and I think someone confirmed with Lelit that this should mean around 9 bar at the puck. Happy to be corrected on this if anyone knows otherwise.

I've noticed the issue over the last several months with all sorts of beans - maybe all of them really. I have a dog and hat med-dark sub so the machine sees many different beans. The roast date is always about right before they get frozen, but the issue has also happened with beans that were never frozen so don't think it's related&#8230;good points though!


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## MediumRoastSteam (Jul 7, 2015)

@tj893 - loosen that screen slightly. As guidelines, only tighten the screen until you can't rotate the shower screen on the dispersion plate, using your fingers only. 
The screw should be finger tight, literally.

see if it improves things.

and I'm assuming you are dosing 18g on a VST basket? (I can't remember what basket you have).


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## Rob1 (Apr 9, 2015)

Not sure if this has been covered already but have you cleaned the grinder recently?

My shots were running perfectly and then I cleaned the grinder and everything looked like yours and there was nothing I could do to change it. The taste got worse too. I cleaned again and made sure to sweep out every last grain of coffee that I might have dislodged and got under the sweeper arms, especially in the recess around the spindle. I also removed the springs and cleaned the gaps in there too. It made some difference but it didn't go back to normal. Eventually it resolved itself. I think it was a combination of slightly messing up alignment and the burrs just reaching a point where they were awkwardly broken in.


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## DavecUK (Aug 6, 2013)

tj893 said:


> From what I've seen around the internet it seems the Elizabeth manometer usually shows 10 bar during the shot, and I think someone confirmed with Lelit that this should mean around 9 bar at the puck. Happy to be corrected on this if anyone knows otherwise.


 The Elizabeth uses the QuietX pump (as I call it) and an expansion valve to control pressure, so 10 bar on the gauge against a blind filter means the max pressure on the puck will be 10 bar. With coffee, if the flow rate through the coffee exceeds the pumps ability to maintain a flow to make 10 bar, the expansion valve will not open, and 10 bar will not be experienced by the puck.


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## MediumRoastSteam (Jul 7, 2015)

@tj893 - that post above from @DavecUK is very insightful. @tj893: Could you do another video but focus on the pressure gauge the whole time rather than the bottom of the portafilter?

On mine, I can see the needle of the gauge starting at around 10bar, and gradually decreasing to approx. 9 bar after 35 seconds or so.


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## ckrhodes (Feb 19, 2019)

I knew it was one or the other with the dark roast vs light roast integrity. Took a 50/50 chance and was wrong haha.

Point still stands that the bean will have an effect though.


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## HVL87 (Dec 17, 2019)

As mentioned earlier in the thread I experience the same issue as @tj893 with light/medium roasts and possibly medium/dark roasts which are not fresh.

As an example, yesterday I opened a medium/light Ethiopian natural roasted on 23rd Aug. It went into an airscape and I decided to make espresso today.

For reference I'm using an ACS Minima paired with a Niche grinder which has had around 2.5-3kg through it. I WDT with a 3D printed tool with 0.4mm needles, use a leveller to create flat tamping surface and tamp with a standard 58.4mm motta tamper. Dose is 17g in an 18g VST basket. I also tried 18g at a slightly coarser setting - same result.

I'm quite particular about puck prep so I don't believe that's an issue 🤔

Here is a video of the shot. Similar pattern from the bottomless with what looks like a change in flow due to puck degradation in the last 1/3rd of the shot.






@Rob1 what you mentioned about your shots after cleaning the Niche is interesting. I'm due to clean mine soon but haven't done so yet - maybe I'll see the opposite result after cleaning, although I can't imagine why. Do you still see a similar flow to the above with your shots/certain beans?

The group pressure gauge reaches just above 9 bar after the initial ramp up and slowly reduces below 9 bar by the end of the shot. As I don't have a flow control kit yet I'm tempted to adjust brew pressure to around 8 bar at the group against a blind basket to see if this helps.


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## Rob1 (Apr 9, 2015)

HVL87 said:


> @Rob1 what you mentioned about your shots after cleaning the Niche is interesting. I'm due to clean mine soon but haven't done so yet - maybe I'll see the opposite result after cleaning, although I can't imagine why. Do you still see a similar flow to the above with your shots/certain beans?
> 
> The group pressure gauge reaches just above 9 bar after the initial ramp up and slowly reduces below 9 bar by the end of the shot. As I don't have a flow control kit yet I'm tempted to adjust brew pressure to around 8 bar at the group against a blind basket to see if this helps.


 Yes I do and I don't see the issue with the flow at all. My shots run for longer than that and to a longer ratio. If you think there's something wrong with your extractions then it makes sense to start changing things but if not don't worry about how it looks through a bottomless portafilter. Especially don't worry about erosion which will always happen whether you can see it on a bottomless or not.


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## tj893 (Apr 17, 2020)

Thanks everyone for the thoughts and interesting discussion, and sorry for taking a while to get back.



MediumRoastSteam said:


> @tj893 - loosen that screen slightly. As guidelines, only tighten the screen until you can't rotate the shower screen on the dispersion plate, using your fingers only.
> The screw should be finger tight, literally.
> 
> see if it improves things.
> ...


 This helped! I must have been over tightening the shower screen which was definitely accentuating the flow pattern.

The key thing at play though has proven to be the freshness of the beans as others mentioned combined with getting the grind level right. There seems no real difference in flavour over the days that flow might gradually change and the coffee still tastes great (thanks Rob1)!

So an interesting thing (for me at least) to consider as a signpost for something to improve, but ultimately a dead end!

Many thanks again to all


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## MediumRoastSteam (Jul 7, 2015)

@tj893 - just letting you know that my extractions are looking now very similar to yours. What changed? The beans! I'm drinking a Kenyan from Foundry Coffee Roasters, roasted medium/light. Requires a very fine grind, tastes great, but the extraction over a bottomless looks dreadful! 🤣🤣🤣🤣🤣


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## tj893 (Apr 17, 2020)

Thanks for coming back with this observation- it's great to get it confirmed. Yep it seems to relate to the viscosity of the shot, and I've continued to see this vary as the beans age with no discernible affect on the flavour (from thick/full and what might be thought of as a "good" extraction visually to the thinner version a week or 2 later).


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