Refractometer Reading Differs
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SJW
As you must brew, so you must drink
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No problems, I also was amazed when Mark explained it to me. Also I meant to say refractometers measure "glucose" specifically not "sugar". Either way the diff between glucose and maltose appears to be where our 3 points disapears at about 1.050 SG.
I am sure someone with more brains than me could explain it better.
Steve
I am sure someone with more brains than me could explain it better.
Steve
ashley_leask
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SJW
As you must brew, so you must drink
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http://www.byo.com/stories/projects-and-eq...-refractometers
This is a good read about half way down on the correction for wort (maltose) instead of sucrose. And it would appear that 1.004 is a std type of correction when read with water for most normal SG beers.
Also this from the Promash site.
Promash Help Excerpt:
"A Brix refractometer reading is based on the known values for percentage sucrose solutions. However, wort contains many substances other than sucrose, and many of them have different refractive indices than sucrose. For this reason, it is necessary to use a correction factor to convert from a Brix refractometer reading of raw wort to the actual gravity of the wort. The literature suggests this factor is between 1.02 and 1.06, with 1.04 often used as a default value.
To determine your own, brewery-specific Brix correction factor:
(1) Take a hydrometer sample of unfermented wort.
(2) Measure its gravity with the most accurate, calibrated hydrometer you have. Do not forget to do the temperature offset calculations. (Alternative: use a digital density meter or pycnometer -- the idea here is to get a very accurate measurement of the actual SG / Plato of the sample.)
(3) Convert this value to Plato if you measured in SG.
(4) Using a zeroed refractometer, take the refractometer reading of the same sample.
(5) Convert this value to Brix if measured in RI or Zeiss units.
(6) Brix correction factor = Refractometer reading (in Brix) / Measured Gravity (in Plato) E.g., Refractometer reading = 13.1 Brix Measured gravity = 12.7 Plato Brix Correction factor = 1.0315
(7) Do this with several different samples and average the results. The literature suggests that the value should be consistent within a particular brewhouse."
This is a good read about half way down on the correction for wort (maltose) instead of sucrose. And it would appear that 1.004 is a std type of correction when read with water for most normal SG beers.
Also this from the Promash site.
Promash Help Excerpt:
"A Brix refractometer reading is based on the known values for percentage sucrose solutions. However, wort contains many substances other than sucrose, and many of them have different refractive indices than sucrose. For this reason, it is necessary to use a correction factor to convert from a Brix refractometer reading of raw wort to the actual gravity of the wort. The literature suggests this factor is between 1.02 and 1.06, with 1.04 often used as a default value.
To determine your own, brewery-specific Brix correction factor:
(1) Take a hydrometer sample of unfermented wort.
(2) Measure its gravity with the most accurate, calibrated hydrometer you have. Do not forget to do the temperature offset calculations. (Alternative: use a digital density meter or pycnometer -- the idea here is to get a very accurate measurement of the actual SG / Plato of the sample.)
(3) Convert this value to Plato if you measured in SG.
(4) Using a zeroed refractometer, take the refractometer reading of the same sample.
(5) Convert this value to Brix if measured in RI or Zeiss units.
(6) Brix correction factor = Refractometer reading (in Brix) / Measured Gravity (in Plato) E.g., Refractometer reading = 13.1 Brix Measured gravity = 12.7 Plato Brix Correction factor = 1.0315
(7) Do this with several different samples and average the results. The literature suggests that the value should be consistent within a particular brewhouse."
