# What's your opinion on this extraction



## nikitas (Sep 24, 2021)

Hi all,

This is my first post here and the beginning of my espresso journey!

I read that using a bottomless portafilter can help in diagnosing problems with puck preparation. But I didn't manage to find a comprehensive guide that explains what to look for exactly in the extraction.

So I filmed an extraction of mine and I would like to ask your opinion on it: are there any obvious sign or mistakes you can see?

The video is available at: https://drive.google.com/file/d/1SrctWomZASLSzfnYDxuBqNYyJe7IE6Tm/view?usp=sharing

About the shot: It's 15g of Red Brick from Square Miles, around 10 days after roasting, grinded in an Eureka Mignon Manuale resulting in 30g of espresso over 30 seconds in an unmodified Rancilio Silvia.

Thank you very much!

Nikitas


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## DavecUK (Aug 6, 2013)

It looked like it choked a bit, then the puck fractures and it started to gush...looked a bit ugly towards the end. This can happen if you grind too fine...I don't know with the Silvia, but can you updose a little as well, that will help.


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## nikitas (Sep 24, 2021)

Thanks a lot Dave - I will try to go coarser and perhaps updose.

Do you happen to have any links that explain how to "read" a bottomless extraction?


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## DavecUK (Aug 6, 2013)

not really, I like to try and make them look like this.


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## nikitas (Sep 24, 2021)

DavecUK said:


> It looked like it choked a bit, then the puck fractures and it started to gush..


 Today I think got a similar behaviour to the one you describe.

I had very slow flow at the beginning of the shot (essentially only drops of coffee) for quite a few seconds and then a considerably faster flow.

Changing the grinding setting a little (half a step in my Niche zero) produced a relatively okay shot that finished in 25 seconds.

I saw the same behaviour a number of times while dialling-in today. I wanted to go a bit finer because the 25 seconds shot was a bit sour for my taste, but when doing that I had this choked behaviour.

Any ideas of what is happening/what can I improve? I am using 18.5g of coffee/38g output recipe.

For what it's worth, I attach the flow rates of the two shots (chocked one and the okay-ish one) recorded via the app I am working on:


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## DavecUK (Aug 6, 2013)

@nikitas you could try increasing the temp, or the increasing the ratio


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## nikitas (Sep 24, 2021)

Thanks again Dave, increasing the temperature helped with the taste, I think.

What could be the reason(s) for having this behaviour? I would expect to have a more smooth increase in shot duration for such a small grinding change..


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## DavecUK (Aug 6, 2013)

@nikitas I don't really know, I have experienced this myself. I think with some coffees, you cross a threshold as you go finer.


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