Dead spots appear later in the shot

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Raglo

#1: Post by Raglo »

I'm pulling shots with the Flair 58 and an IMS 18g basket. The puck is very carefully prepped with WDT and I'm using a levering tamper so there's no issues with an uneven tamp. Now my shots start out perfectly, the entire basket fills up evenly and comes together into a single stream fairly quickly but at about 10 - 15g out several dead spots start to show up on the basket. Any idea why this is happening? I'm brewing a medium roast with 18g in and 36out and I've dialling in to have the shot end at around 30 secs.

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zix
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#2: Post by zix »

Are you using the Comandante mk3 you had before to grind for espresso with the Flair58?
LMWDP #047

Raglo (original poster)

#3: Post by Raglo (original poster) »

BUMP

fronesis

#4: Post by fronesis »

Raglo wrote:I'm pulling shots with the Flair 58 and an IMS 18g basket. The puck is very carefully prepped with WDT and I'm using a levering tamper so there's no issues with an uneven tamp. Now my shots start out perfectly, the entire basket fills up evenly and comes together into a single stream fairly quickly but at about 10 - 15g out several dead spots start to show up on the basket. Any idea why this is happening? I'm brewing a medium roast with 18g in and 36out and I've dialling in to have the shot end at around 30 secs.
30 seconds total?
Or 30 seconds after the first drop?

If it's the former, that's *way* too fast. Even if it's the latter, that's a pretty quick shot - at least from my experience on a Robot. I usually take close to 20 seconds before I see the first drop, and finish up the shot (at 2:1 ratio) at 50-60 seconds.

I don't have a definitive answer, but my best guess is that your puck is just degrading quickly and your grind is a bit too coarse.

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zix
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#5: Post by zix »

This is why I asked about the grinder. If there are lumps of fines near the bottom of the puck because the OP is using a grinder with too many fines, or too many "boulders", it doesn't really matter how well the puck is prepared.

It might well be (although I am aware that some now might reach for stones to throw...) that you might be better off with a portafilter with spouts so you can't see the "problems", grind a bit finer, tamp very lightly, and just pull a 4 bar shot. Then taste and see how you like it.

Total time is not always important. With a manual lever you can pretty much vary preinfusion from 0 into infinity. And if it starts gushing, you can just stop the pull.
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emradguy
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#6: Post by emradguy »

I suggest your puck is not as evenly prepared as you think, and is not fully saturated when you finish preinfusion. The high viscosity of the espresso early on is causing enough surface tension on the bottom of the basket to cover up dead spots. When the viscosity drops enough, that effect is removed and the dead spots are revealed.

Your solution might be as simple as lengthening the preinfusion time, but I imagine you need to grind a bit finer as well, and make sure your WDT involves the entire depth of the puck. I would focus all of my efforts there. What you want to watch for during the extraction is uniformity in distribution, size and timing of the first appearance of espresso through the basket holes, across the entire surface, before the stream starts. That means getting down below the basket as you pull the shot, or using a shot mirror.

While leveling tampers are great, you should remember they aren't going to fix anything. Rather, they simply help you maintain what you did in the previous steps while you compress the bed. Your dry puck should look very even, and level, before you tamp.

As implied above, the quality of your grinder is important, and it would help us to know what you're using.

Lastly, remember that it doesn't matter one bit what the extraction looks like if the resultant shot tastes great.
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PIXIllate
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#7: Post by PIXIllate » replying to emradguy »

This is fantastic advice.

mathof

#8: Post by mathof »

emradguy wrote: Lastly, remember that it doesn't matter one bit what the extraction looks like if the resultant shot tastes great.
It matters to me when that happens, as I wonder if my next shot could taste even greater were I to change a parameter or two.