Hey all first post here, although I posted on CF and it’s a bit quiet! I’ve got a Lelit Bianca and Mahlkönig x54 and all had been going very very well until the last couple of weeks. Inexplicably, my extractions have gone hugely inconsistent and I can’t work out why. Same grind setting, same dose, same final output, same tamp pressure. This afternoon I got a 20 odd second shot, a 40 odd second shot and one that choked the machine to the point I was getting drips at 50 seconds. Up until this started I could happily make multiple coffees in a row with virtually identical extractions and consistency in the cup. I’ve tried grinding coarser, and I’ve tried two different beans. Still getting the same results. Pressure on the Bianca both at the pump and at the group are as normal, and running the pump without the PF flow seems to be completely normal. The paddle is wide open on all of the above too. To my eye, the grinds look normal, no clumping or obvious uneven grind. Any ideas on what could be causing this? It’s a real head scratcher as I’d been getting fantastic results prior, and easily dialling in multiple coffees that would stay dialled in. Thanks!

Strange inconsistent extraction times with constant settings

dutchy101

How fresh are the beans you are using?

Cuprajake

Do you weigh the grinds into the pf? Do you purge the grinder?

How long in between shots?

Ernie1

The first beans I noticed the problem on were roasted 18th December, a dark-ish Brazilian blend. The ones I tried today were roasted a week ago, lighter single origin.

I tend to purge a lot between grind settings/beans, usually about 20g. The x54 has a pretty high retention.

To clarify though, the inconsistent extractions are happening when not changing setting/bean.

I grind into a dosing cup to weigh, then into the PF, and use a WDT tool to distribute. No levelling, just tamp.

I don’t wait particularly long between shots,

just enough time to rinse the screen, knock-out and dose the PF.

Again though, all of this was going fine until a couple of weeks ago.

Rob1

Do you single dose the grinder and have you always done that? The only thing I can think of is you may have previously been using the hopper and have switched to single dosing. Other than that a fault with the grinder…have you previously tried adjusting it to grind fine without having it running? Or disassembled for cleaning?

Cuprajake

Agree its grinder related. And not the forst person to seem to have issuses with the x54

Ernie1

Thanks yeah unfortunately looks like you both might be right.

I’m not single-dosing for espresso and use a dedicated SD grinder for brew, I’ve followed the same pattern for years- keep the hopper topped up with about a day’s worth of beans each day (about 80-100g). The rest stays in airtight canisters. I only change the grind setting if I change beans or the results in the cup suggest a tweak might be needed.

I’ve not had much sympathy from the retailer when I’ve mentioned issues with the grinder before (I got massive clumping when I first got it which has admittedly eased).

I’m reluctant to disassemble the grinder before I’ve spoken to retailer but will inspect the burrs if they suggest it.

I must admit on good days this grinder is great, but it’s been temperamental to say the least.

Ernie1

Just got exactly the same bizarre results…

18.5g - 36g - 46 seconds

18.5g - 36g - 22 seconds.

Such an enormous variation.

I’ve noticed the timer on the grinder is erratic too, I never relied solely on it but it’s useful to get within 0.5g and was pretty accurate.

Those above shots, with a 17 second timer I ground 17g and then 22g. Again, really unusual results that seem to have only just started.

It’s like a burr is loose or something but it sounds totally normal. I’ll call the retailer on Monday and see what they say.

MediumRoastSteam

Ernie1 - that’s crazy. Short of taking the burrs apart and access to the grinding chamber, and make sure everything is clean and unobstructed, I wouldn’t know what else to say. 😢

Ernie1

As an update, tried another coffee today, same results. Thought I’d got it dialled in and then subsequent shots extracted entirely differently despite the exact same grind setting and input/output volume.

I double checked the scales too as I thought that could be a factor if they’re playing up but they’re fine. Has to be the grinder.

DavecUK

Ernie1 As an update, tried another coffee today, same results. Thought I’d got it dialled in and then subsequent shots extracted entirely differently despite the exact same grind setting and input/output volume.

I’m not saying it’s not the grinder, it may be, but not for the reasons you might think…The question is really why are these variances occurring… a few things:

Do you use a bottomless portafilter, if not, start using one.
can you put up a video of your shots
do everything at a full open paddle position…just to standardise that aspect of things (let us know the flow rate per minute from an empty group for the full open paddle.

Ernie1

Thanks both,

I’m using a spouted portafilter, I haven’t actually unwrapped the bottomless one since I bought the Bianca!

I’ll get a video using the bottomless, can we upload videos directly here or will it need to be hosted?

DavecUK

Ernie1 can we upload videos directly here or will it need to be hosted?

You upload to YouTube as unlisted, then paste the link here. This keeps our footprint low on what is a completely free service.

Ernie1

Perfect, thanks. Will report back!

Ernie1

Inexplicable turn of events this morning when recording a video…

I used the bottomless PF (first time I’d ever used one) and pulled five back-to-back shots that extracted 1:2 in pretty much the same time and tasted fantastic.

I then switched to the spouted and got two good shots in a row which again extracted in much the same time…

Completely clueless as to why things seem fine now. I changed absolutely nothing in the workflow other than the portafilter. Only thing I did do was wash the spouted PF while I had it removed? Perhaps a slight blockage? I clean it every few days anyway so unlikely but I can’t think what else has fixed it!

Here’s the video, feel free to critique the extraction, as above, I’m new to using bottomless portafilters.

Video is intentionally portrait as I assume a lot of viewers are using their phone.

DavecUK

The spouted filter hides the moment a puck fractures and starts to flow faster. With a bottomless filter there is nowhere to hide. Keep using it and the time when you get the bad extractions, it will be quite obvious the puck has fractured in one or more places. You will see, barbers pole striping, tornados, sprizting etc…plus a very noticeable change in the flow the moments after the puck fractures.

Causes can be, poor grinder, poor prep, aging beans…. I would suggest what’s happened sort of proves there is nothing wrong with the grinder or the coffee!

Ernie1

Certainly seems like it’s the prep!

Thanks for the help.

As a side note, is there some kind of object that allows one to tamp a bottomless PF on a level surface? The edges of my worktop are curved so those mats that sit on the edge don’t work.

DavecUK

Ernie1 As a side note, is there some kind of object that allows one to tamp a bottomless PF on a level surface? The edges of my worktop are curved so those mats that sit on the edge don’t work.

I don’t use such accessories, but I am sure others will have some suggestions.

MediumRoastSteam

Ernie1 The edges of my worktop are curved so those mats that sit on the edge don’t work.

You can buy a tamping station… Or you can tamp on a piece of wood… Or you can tamp on a group gasket… - All “accessories” I’ve used until very recently. ;-)

Ernie1

Ok great thanks, time to search the house for a random object of suitable dimensions!

Ernie1

Just when I thought it was fixed…

Tried a new coffee today. Guatemalan from Rave.

Got it dialled in, or so I thought. 28 seconds for a 1:2 yield, tasted good. Next shot, 24 seconds for the same dose and yield, thin and underextracted.

Rather than faff around with the grind setting and lose purge waste I just upped the dose by 0.5g as I only have a small bag and it’s no longer available to buy.

22 seconds…

Prep is identical to what I was doing before, using a measured tamp.

I checked the flow rate on the Bianca, I got a constant 100ml in 16 seconds five times in a row with the paddle fully open with no PF fitted. Is that about right?

I spoke to the retailer of the x54 yesterday and the way I had to explain things made me think sadly they’re not actually clued up on the ins-outs of coffee prep. They just referred me to an email from MK that said ‘this can happen when switching grind settings’… despite explaining that I hadn’t even touched the grind setting between shots.