# Refractometer,early days...



## ronsil (Mar 8, 2012)

I fancied trying out a VST Refractometer to see what it could do to assist in producing the best espresso I can, given the equipment I use.

Enjoyed setting it up this evening & here is my first attempt using Steampunk Velos.










Its a Bean I know well & always enjoy.

I know a growing number here are now using these instruments & would welcome any comments on this 1st result.

All caffiend out for this evening so will have to wait till morning to continue.


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## Mrboots2u (May 10, 2013)

Try dropping the dose and going finer to get over 21 EY and then see if that tastes better it not

Say 18 into 38 down a couple of micro notched

Are u using VST baskets?


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## MWJB (Feb 28, 2012)

Sorry Ron,

It looks like we only have the design parameters, not the measured yield from your TDS reading?


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## ronsil (Mar 8, 2012)

OK - I'm the novice with this one.

How do you bring up the measured yield?


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## Mrboots2u (May 10, 2013)

MWJB said:


> Sorry Ron,
> 
> It looks like we only have the design parameters, not the measured yield from your TDS reading?


Has Ron just not put the stuff he measured in the design boxes?


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## ronsil (Mar 8, 2012)

Mrboots2u said:


> Try dropping the dose and going finer to get over 21 EY and then see if that tastes better it not
> 
> Say 18 into 38 down a couple of micro notched
> 
> Are u using VST baskets?


Will try your suggestions in the morning & let you know. Thanks



> Has Ron just not put the stuff he measured in the design boxes?


 Yes just entered TDS reading the rest is what I have always used for the Velos.

Using 20g VST as I have always done


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## Mrboots2u (May 10, 2013)

What baskets Ron?


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## MWJB (Feb 28, 2012)

Mrboots2u said:


> Has Ron just not put the stuff he measured in the design boxes?


Yes, I see...Markbot is not capable of abstract thought...syntax error....circuits overloading...fzzzzzt...pop!


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## ronsil (Mar 8, 2012)

So just completing my 1st week with the refractometer.

Its a very interesting piece of kit. Puts a different slant on espresso extraction.

Out of the window goes the sacred, for me, max extraction time of 30 seconds. We are now talking 40/48 seconds to produce a 33 grams shot.

Here is an updated chart showing how we arrive at this point:










This result gives me the strength, towards ristretto, that I prefer. I now have it shared between my iMac, Macbook & Android phone.

I have to admit probably a bit reluctantly that it is leading me on to a fuller & sweeter taste.

My thanks to Boots for passing me several pointers along the way. I have put a profile on the Vesuvius that I can stop as soon as the required weight is reached. To prevent any after run through the spouts I slide a plastic lid over the top of the cups as I stop the pour.

In the end everything is still down to personal taste but this gadget (sorry for using the word) does save a lot of trial & error & coffee wastage.

The Family think I'm playing with a school chemistry set. They may just be right.


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## The Systemic Kid (Nov 23, 2012)

Good to hear you're finding the refractometer useful, Ron - shortcuts a lot of guesswork and the figures don't lie


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## Charliej (Feb 25, 2012)

Just a quick question here, I'm just wondering what is going on the most recent screenshot Ron posted, the Brew water weight is down as 51.6g but the beverage weight is down as 33g I'm confused.

Ron I sacrificed that particular holy cow of 30 seconds on the altar of progress some time ago and have just been going on desired brew weight now and getting far better results. I'm not sure why a lot of the newcomers to the forum seem to think 25 seconds is enough time to pull a double shot though, to me a double of a decent weight from 20g has always tasted under-extracted in 25 seconds to me.


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## Mrboots2u (May 10, 2013)

Brew weight is presumably what Ron measured out and then inputted

Coffee tools will have used some formula to back calculate the water that went into the puck. Some. Of which will have been absorbed...


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## Mrboots2u (May 10, 2013)

How long your shot is and jow tasty will some some degree depend on the quality of grinder and uniformity of particle size...

Dose - brew weight - TDS are the variables that define extraction yield.

Grind finer = higher TDS longer shot time

Grind coarser lower TDS

But then the EY will be a function of the dose brew weight and TDS...

Also don't forget temp effecting how quickly you get that EY too..

Ron has some pretty high end equipment and a great grinder to push extraction yields and time limits with.

Might not be so tasty a recipe from say a non temp stable machine. And a grinder of less consistent particle size


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## The Systemic Kid (Nov 23, 2012)

Charliej said:


> Just a quick question here, I'm just wondering what is going on the most recent screenshot Ron posted, the Brew water weight is down as 51.6g but the beverage weight is down as 33g I'm confused.


Formula for measuring extraction yield is: brewed weight divided by dose weight and multiplying result by TDS score.

Example: brewed weight of 40grms; dose weight of 20grms - TDS of 10: 40/20 x 10 = 20% extraction yield. The brew water weight doesn't impact on the figures - what comes out does.

For the hawk-eyed: Ron's figures are 33grms out divided by 20grm dose times TDS score of 12 which comes out at 19.8% extraction yield. Why the difference? VST software is adjusted for moisture content hence the difference in results.


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## jeebsy (May 5, 2013)

How do you get the tds?


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## garydyke1 (Mar 9, 2011)

jeebsy said:


> How do you get the tds?


Refractometer measures it


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## jeebsy (May 5, 2013)

So that's the money shot


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## garydyke1 (Mar 9, 2011)

jeebsy said:


> So that's the money shot


Without it you've no hope in hell of knowing extraction %


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## The Systemic Kid (Nov 23, 2012)

jeebsy said:


> How do you get the tds?


That's the refractometer's key function - as Gary says, it measures it. Couple of drops of your coffee sample on to the measuring lens and the laser takes multiple reading before averaging them and giving you a TDS score. You input this and the other key data - brewed coffee weight and dose weight into VST coffee tools and it gives you extraction yield.


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## Mrboots2u (May 10, 2013)

garydyke1 said:


> Without it you've no hope in hell of knowing extraction %


I thought your finger was a refractometer....next stage of coffee evolution.....


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## The Systemic Kid (Nov 23, 2012)

Brings a new dimension to 'suck it and see'.


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## garydyke1 (Mar 9, 2011)

I can guess TDS of filter coffee pretty well now. 1.20 / 1.30 / 1.40 are easy to tell apart by mouthfeel alone

If its chemex 30/500 and 1.25-1.33% I'm in my happy zone


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## MWJB (Feb 28, 2012)

Charliej said:


> Just a quick question here, I'm just wondering what is going on the most recent screenshot Ron posted, the Brew water weight is down as 51.6g but the beverage weight is down as 33g I'm confused.


Brew water weight includes that calculated as being absorbed by the puck. The output figures are the most pertinent.


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## The Systemic Kid (Nov 23, 2012)

garydyke1 said:


> If its chemex 30/500 and 1.25-1.33% I'm in my happy zone


Plus one for that.


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## garydyke1 (Mar 9, 2011)

Another interesting thing I have noticed .

2 identical chemex, same coffee, same water , same dose, same yield, both TDS 1.26%

Uber grinder - yum

EK - under extracted

2 identical chemex, same coffee, same water , same dose, same yield, both TDS 1.34%

Uber grinder - over extracted

EK - yum


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## MWJB (Feb 28, 2012)

garydyke1 said:


> Another interesting thing I have noticed .
> 
> 2 identical chemex, same coffee, same water , same dose, same yield, both TDS 1.26%
> 
> ...


Now throw a Kone in the mix...


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## Mrboots2u (May 10, 2013)

MWJB said:


> Now throw a Kone in the mix...


You had too didn't you..


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