Refractometer software, WARNING!

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yojimbo
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Re: Refractometer software, WARNING!

Post by yojimbo » Sat Apr 14, 2012 8:19 pm

Been brewing today and tinkering at the same time i made up 3 sugar solutions got them to 20 c and measured them with hydrometer then the refractometer they tally up spot on found formula to convert gravity to brix for sucrose on wiki . Going to have a look at the correction factor on beer engine brew went well got og of 1.063 brix reading was 15.6 I convert the 1.063 og to a brix value of 15.42 . I presume the differance bettween the two brix values must be the correction factor ?


Not used the refractometer once fermentation has started but have noticed its out compared to the hydrometer but not by much fot the og.
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yojimbo
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Re: Refractometer software, WARNING!

Post by yojimbo » Sat Apr 14, 2012 8:29 pm

Also just had a thought , on beer engine does the corrected brix value mean thats the equivilant sucrose brix value ?

Think that makes sense lol.
Seems my correction factor is 1.01 that gives me og 1.063 , brix reading of 15.6 and a corrected brix of 15.45 .
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orlando
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Re: Refractometer software, WARNING!

Post by orlando » Sun Apr 15, 2012 7:54 am

GW emphasises that a refractometer reading of wort is only ever an approximation. Because a refractometer is set up to read the refractive index of sucrose wheras wort is a mixture of maltose & dextrins and obviously changes that mixture depending upon what you're brewing. As he says "the calibration factor is not a fixed figure, but varies according to wort composition. Different types of beer may require different calibration factors. Also, a hydrometer responds to all dissolved solids, solids such as protein, but the refractometer does not. This implies that different calibration factors may be required at different stages of the brewing process

This is before the complication of fermentation and how yeast and CO2 bubbles mess with it further.

The take home lesson for me in all this then is if you are going to use a refractometer you have to use a hydrometer as well to calculate the calibration factor for EACH brew and not have a single default setting as different brews will of course have different fermentables, how many of us know that and act accordingly?.
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Re: Refractometer software, WARNING!

Post by gregorach » Mon Apr 16, 2012 10:05 am

orlando wrote: The take home lesson for me in all this then is if you are going to use a refractometer you have to use a hydrometer as well to calculate the calibration factor for EACH brew and not have a single default setting as different brews will of course have different fermentables, how many of us know that and act accordingly?.
Or you just have to accept that none of these measurements are actually that accurate anyway. How good do you think your hydrometer really is?
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orlando
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Re: Refractometer software, WARNING!

Post by orlando » Mon Apr 16, 2012 10:34 am

Fair point, I guess you have to have something and as long as they are "equally wrong" then it will allow a degree of consistency beyond merely guess work.
I am "The Little Red Brooster"

Fermenting:
Conditioning: Distant Sun, St. Petersburg (RIS)
Drinking: Black Dog, Almost Gold, Closer To The Edge (Elgood's North Brink Porter)
Up Next: Duke of Jarl (Reprise), Mild In The Country, London Calling, Gertcherbrewed
Planning: Spring drinking beer.

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