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Brix and SG Discrepancy

I am having a hard time trying to figure out what is going on. I calibrated my refrectometer with distilled water that was sitting in the same room right before I did this. Room is about 70 deg.

I have two separate beers fermenting and I am getting a large discrepancy.

My english bitter which has been fermenting for 11 days I get a SG of 1.010 and brix of 3.7 they seem to be relatively close, but still off by a bit. 3.7 = ~1.014

The Blonde ale that I have seems to be much different I am getting an SG of 1.009 and brix of 4.3. This is way farther off than I am expecting as 4.3 = ~1.017.

I am highly confused and think I may be doing something wrong with the refrectometer, as I checked twice with two different hydrometers.

Any pointers or tips?

Have you tried this: http://www.northernbrewer.com/refractometer-calculator/

The presence of alcohol will throw off a refractometer reading.

[quote=“brans041”]I am having a hard time trying to figure out what is going on. I calibrated my refrectometer with distilled water that was sitting in the same room right before I did this. Room is about 70 deg.

I have two separate beers fermenting and I am getting a large discrepancy.

My english bitter which has been fermenting for 11 days I get a SG of 1.010 and brix of 3.7 they seem to be relatively close, but still off by a bit. 3.7 = ~1.014

The Blonde ale that I have seems to be much different I am getting an SG of 1.009 and brix of 4.3. This is way farther off than I am expecting as 4.3 = ~1.017.

I am highly confused and think I may be doing something wrong with the refrectometer, as I checked twice with two different hydrometers.

Any pointers or tips?[/quote]

I’m guessing your refract reads only in brix, so for example the 3.7 reading is refract and the SG of 1.010 is hygro? According to the Schwartz chart 3.7 should equal ~ 1.014

My refract is both scales…the SG tends to be a bit off from the above mentioned chart.
As the previous poster said, these are both post - ferm so a calculation is needed.

Two more considerations for the bitter numbers (wouldn’t explain the wide gap you’re seeing in the blonde)…

  1. Are you sure your hydro’s read exactly 1.000 in your brewing water at the calibration temp?
  2. I find it’s sometimes very difficult to get an accurate reading of my refractometer. May be off +/- .2 brix just because of this.

Combine these two issues and you have the potential for a .004 point discrepancy.

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