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Bottomless shot diagnosis please!


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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…

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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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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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…

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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14 minutes ago, tj893 said:

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…

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

 

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. 

Edited by Rob1
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@tj893 - which grinder? Which beans?

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Current: Lelit Elizabeth / Niche Zero / VST baskets / Distilled water + 100mg NaCO3/L

Previous: Gaggia Classic | Eureka Mignon | Rocket Cellini Evo | Profitec 700 | Profitec T-64 | Gene Cafe CBR-101 | Kinu M68 | Feldgrind 2 | La Pavoni Europiccola 2012

Also at: CoffeeTime Forum & Niche Zero Owners Group

 

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@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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@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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Current: Lelit Elizabeth / Niche Zero / VST baskets / Distilled water + 100mg NaCO3/L

Previous: Gaggia Classic | Eureka Mignon | Rocket Cellini Evo | Profitec 700 | Profitec T-64 | Gene Cafe CBR-101 | Kinu M68 | Feldgrind 2 | La Pavoni Europiccola 2012

Also at: CoffeeTime Forum & Niche Zero Owners Group

 

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@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…

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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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Current: Lelit Elizabeth / Niche Zero / VST baskets / Distilled water + 100mg NaCO3/L

Previous: Gaggia Classic | Eureka Mignon | Rocket Cellini Evo | Profitec 700 | Profitec T-64 | Gene Cafe CBR-101 | Kinu M68 | Feldgrind 2 | La Pavoni Europiccola 2012

Also at: CoffeeTime Forum & Niche Zero Owners Group

 

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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?

Edited by HVL87
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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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36 minutes ago, 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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Current: Lelit Elizabeth / Niche Zero / VST baskets / Distilled water + 100mg NaCO3/L

Previous: Gaggia Classic | Eureka Mignon | Rocket Cellini Evo | Profitec 700 | Profitec T-64 | Gene Cafe CBR-101 | Kinu M68 | Feldgrind 2 | La Pavoni Europiccola 2012

Also at: CoffeeTime Forum & Niche Zero Owners Group

 

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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.

Edited by newdent
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30 minutes ago, 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.

Edited by newdent
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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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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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