# Playing with numbers!



## DavidBondy (Aug 17, 2010)

I have been fiddling around with various calculations etc. to get the best cup that I can from my K10 / L1 combination. I've also been playing with my newest toy - the VST Refractometer.

This is what I discovered:

1) My slight dribbling from the PF when first pulling the lever was due, I am sure to poor distribution and slight clumping from the K10. This is far worse with dark beans (which is how I roast mine) due to the small amount of oil on the surface. In order to minimise this when making my measurements, I ground into a small bowl, sieved with a tea strainer into a larger one then carefully dosed the IMS 26.5mm PF trying to be as even as possible (per Scott Rao's book). I did a careful nutate with my new Torr Goldfinger Trapez. Almost no pressure, just levelling and polishing.

2) My "sweet spot" with the dark OBJ (roasted ten days ago) is: 17g in for 30.6g out (1:1.8) in 30 sec (including 6 sec pre-infusion).

3) My TDS as measured is 10.70% (extraction 19.96%) which puts me just above and to the right of the line on the Universal Brewing Chart. I'll have to look into exactly what that means!

The coffee was exactly what I was looking for in terms of taste with deep rich and slightly smoky flavours.

I just thought that I would share this with you all - just in case anyone is interested!!

DB


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## The Systemic Kid (Nov 23, 2012)

Interesting David. Could you upload a pic of Coffee Tools results as, for the inputs you give, I get a marginally higher extraction yield - 19.9%.


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## DavidBondy (Aug 17, 2010)

Patrick, you are absolutely right! I (mistakenly!) recorded the DESIGN extraction not the measured! It should have read 19.96% - I will amend the original post! Here is a screenshot from the Mac application (although I actually use the iPad most of the time)!.

View attachment 7763


DB


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## The Systemic Kid (Nov 23, 2012)

That's reassuring, David - was beginning to think there was something wrong Yield shows you are bang on the ball park.


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## DavidBondy (Aug 17, 2010)

The Systemic Kid said:


> That's reassuring, David - was beginning to think there was something wrong Yield shows you are bang on the ball park.


Fact is that I am a lawyer by training not a mathematician (I leave that to my cousin after whom Bondy's Theorem is named!!!)!

DB


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## The Systemic Kid (Nov 23, 2012)

Just checked out Bondy's theorem - didn't understand any part of it!


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## DavidBondy (Aug 17, 2010)

Neither do I. He tried to explain it to me once but to no avail!

He is teaching in Paris right now and running a little gallery on the left bank. He is linking mathematics and photography - don't understand that either!!


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## Orangertange (Jul 4, 2013)

Cheers David, got some mahogany roasts jampit that I'm struggling with a bit already worked out that it needs 17g (normally dose 18) will try up the timing and liquid out, tomorrow


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## Charliej (Feb 25, 2012)

DavidBondy said:


> Neither do I. He tried to explain it to me once but to no avail!
> 
> He is teaching in Paris right now and running a little gallery on the left bank. He is linking mathematics and photography - don't understand that either!!


Maybe some fancy digital version of photography by numbers?


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## DavidBondy (Aug 17, 2010)

Charliej said:


> Maybe some fancy digital version of photography by numbers?


Don't know Charlie, they just look like photographs to me! Here is his website: http://en.mindseye.fr/index.php

DB


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