# Dead spot on the center of your basket during extraction?...



## Dylan (Dec 5, 2011)

So I had this problem for a while, and couldn't quite figure out what was happening. I ended up making a 'wiper' that would create a crater in the center of the puck before tamping, but this wasn't ideal and didn't always work to boot. Today I decided to try and fault find, and I swapped out the IMS screen I have in there for a bog standard e61 spot welded one, didn't really expect it to solve anything but was my first point of elimination.

Anyway I locked in the PF and then remembered I hadn't flushed, pulled out the PF and when checking to see if the puck had got any water on it already I see...










Shower screen indentation... bugger me that was the problem all along. The puck had been too close to the screen, so there hadn't been enough room for the water to form over the top of the puck, so it just went directly from screen to puck, missing out the 'blank' in the center and causing my dead spot.

I was dosing 18g in a 18g VST, and going down to 17g gives a much better pour. I think this is also a symptom of when I began to tamp lightly, I found great benefit in that it was much easier to tamp evenly with a light tamp, and achieve the same light pressure each time, but being that the puck is larger it may well have been the root of my center dead spot.

Anyway, lesson learnt.. onward.


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## mremanxx (Dec 30, 2014)

i get this on the classic, I feel like I'm in no mans land sometimes. @ 18g way too much and no headspace down to 14-15g now, I tried using the 21g basket but was worried that I would be flooding the top of the puck, too green at this to know what is the better option.


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## Glenn (Jun 14, 2008)

If you dose correctly the puck will expand and press against the shower screen and you will get an indent

If you dose too little the puck is likely to be wet and the extraction uneven


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## Dylan (Dec 5, 2011)

mremanxx said:


> i get this on the classic, I feel like I'm in no mans land sometimes. @ 18g way too much and no headspace down to 14-15g now, I tried using the 21g basket but was worried that I would be flooding the top of the puck, too green at this to know what is the better option.


Follow the test shown here - http://www.home-barista.com/vibiemme-domobar-super-review-espresso-performance-singles.html

It will allow you to get the right amount of coffee in your basket.

18g should be the correct amount of coffee for an 18g basket, the bean type can make a +/-1g or so difference but you really should be getting right down to 14g. Where is your double basket from? If it is not defined as 18g specifically it may be that it actually isn't supposed to contain 18g. After all a 'single' is supposedly 7g, so in this light a 'double' should be 14g, but the much more common amount in 18g.

Very generally speaking, the top outer edge of your tamper should sit roughly level with the inner edge of the basket when tamped.


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## jeebsy (May 5, 2013)

Dylan said:


> Very generally speaking, the top outer edge of your tamper should sit roughly level with the inner edge of the basket when tamped.


Depends on the tamper, Shirley


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## The Systemic Kid (Nov 23, 2012)

Don't call me Shirley.


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## mremanxx (Dec 30, 2014)

Dylan said:


> Follow the test shown here - http://www.home-barista.com/vibiemme-domobar-super-review-espresso-performance-singles.html
> 
> It will allow you to get the right amount of coffee in your basket.
> 
> ...


The basket came with the classic so I have to presume it is a gaggia, everything else was in the box. I am sure that I have read elsewhere on the forum that the classic can struggle to hold 18g, with regards to the 7g and 14g statement, if this is deemed the norm why does almost everyone on here quote 18g? Is the case that this figure has become the norm only here?

Thanks for the link will read it


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## mremanxx (Dec 30, 2014)

Will try the coin trick a five pence piece?


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## stevogums (May 8, 2013)

Glad this topic has started .

Its a dilemma I found myself in recently ,decided to use just two vst sizes one being 15g other 18g.

If the bean I'm using requires fine grind to get desired ratios I'm ok in the 15g but as soon as I have to go courser I find myself betwix and between .

I was trying to stick to 15.8g for every bean but find that impossible in the 15g basket and it means I have to dose down if using that basket to 14.8g .

If I use the 18g basket find myself getting indifferent results if I stick with the 15.8 g even if I dose up , should I be able to get 15.8g in the 15g vst for all beans as I'm sure I've read the vst is + or - 1.

Trying to keep most of variables the same which has served me well up to now,and most of the time good results .


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## mremanxx (Dec 30, 2014)

Going by what I have read would this not mean that the OP's issue isn't contact with the showerscreen as his marking look light


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## Dylan (Dec 5, 2011)

mremanxx said:


> The basket came with the classic so I have to presume it is a gaggia, everything else was in the box. I am sure that I have read elsewhere on the forum that the classic can struggle to hold 18g, with regards to the 7g and 14g statement, if this is deemed the norm why does almost everyone on here quote 18g? Is the case that this figure has become the norm only here?
> 
> Thanks for the link will read it


18g is absolutely 'normal' for a double basket. But there are all kinds of sizes made by various manufacturers. My point was that your basket is not definitely 18g, unless someone who knows as much has said so or it says so in your manual.



jeebsy said:


> Depends on the tamper, Shirley


"very generally"



mremanxx said:


> Going by what I have read would this not mean that the OP's issue isn't contact with the showerscreen as his marking look light


There should be a gap (as per the coin test) between shower screen and puck for the water to form just before extraction begins. It is essential for even extraction. The mark in my puck shows that a dry puck is touching the screen, causing a dead spot.

I use a 2p for the coin test.


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## mremanxx (Dec 30, 2014)

I got a fairly deep imprint with only 16g, just a light one with 15g so that is my limit with this basket.

What I don't get is if 1:2 ratio is deemed the norm in say 25-30sec why is 18g quoted a lot as I thought the ratio was more important and not the weight of coffee.


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## Dylan (Dec 5, 2011)

mremanxx said:


> I got a fairly deep imprint with only 16g, just a light one with 15g so that is my limit with this basket.
> 
> What I don't get is if 1:2 ratio is deemed the norm in say 25-30sec why is 18g quoted a lot as I thought the ratio was more important and not the weight of coffee.


18g is just widely accepted as the 'normal' double basket. But this is not universally true as some baskets are different sizes.

The 1:2 is the important bit. If your basket holds 15g then extract about 30g as a starting point, taste and adjust from there. Be aware that extraction times could vary a bit if you basket only has 15g in it, but they might not, it depends on how the basket is made.


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## Mrboots2u (May 10, 2013)

mremanxx said:


> I got a fairly deep imprint with only 16g, just a light one with 15g so that is my limit with this basket.
> 
> What I don't get is if 1:2 ratio is deemed the norm in say 25-30sec why is 18g quoted a lot as I thought the ratio was more important and not the weight of coffee.


Hi changing a ratio will effect the mouthfeel and taste of a drink

Changing the time you brew a ratio in , will also effect how that particular ratio will taste.

Simplistically upping a dose and keep the ratio the same , you are making a bigger drink for one...

This might help you

http://coffeeforums.co.uk/content.php?378-Espresso-and-Finding-A-Balanced-Cup-Brew-Ratios


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## hotmetal (Oct 31, 2013)

I find changing dose by more than a gram has a big effect on shot time. However, I have had dead spots in the middle of my 18g vst when dosing above 18.5. Very noticeable with this month's DSOL.


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## mremanxx (Dec 30, 2014)

Mrboots2u said:


> Hi changing a ratio will effect the mouthfeel and taste of a drink
> 
> Changing the time you brew a ratio in , will also effect how that particular ratio will taste.
> 
> ...


Yeh read this before Boots, I have been concentrating on the 1:2 ratio in around the 25-30 seconds mark. I get nothing really tasting the espresso neat, I do try and unless it's really sour or bitter I struggle. I know if I like the shot after I have added water or milk, I occasionally do a 21g in 30-31g out and make a flat white, normally tastes nice.

Maybe I weird


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## Xpenno (Nov 12, 2012)

Baskets and shower screens come in many different shapes and sizes. I always use the coin test with a 20p to check the head space of the puck. Has always worked for me. That said different beans have different densities so you may have to up/down dose by up to half a gram to achieve consistent results between been as well.


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