Refractometer Question

[Squaregrouper]

Background- One of my dogs got a hold of my hydrometer and cylinder. Thus, I no longer have a hydrometer. I am an accomplished marine aquarist- 8yrs in filtration and water quality at a major public aquarium. For marine aquariums I use a refractometer.

Question- I have read that the alcohol skews refractometer readings for FG and I need a brix refractometer for homebrewing. This doesn't make sense to me.
Is this true? If so, why can't I use a specific gravity refractometer in place of a hydrometer for FG testing. Is there something which doesn't translate? To me, it shouldn't matter.

Please advise,
Kyle/Squaregrouper

 

[dk21]

No refractometer will give you accurate measurements once alcohol is present. It has something to do with how it bends the light. You can supposedly get reasonable results by using a calculator like this one: http://seanterrill.com/2012/01/06/refractometer-calculator/

It requires knowing your correction factor. I've never tried it out since I just use my hydrometer for FG. You should do some reading about it.

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