Refractometer for FG

Discussion in 'Beginners Brewing Forum' started by BrainYYC, Jan 22, 2021.

  1. BrainYYC

    BrainYYC Active Member

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    Hi folks, I believe I recently read a post on here from a fellow brewer that a refractometer can be used for 2-3 days in a row to check stabilized gravity. Understanding the actual reading won’t be accurate, I’m talking about pulling a small sample and simple checking for a similar readings to indicate fermentation’s complete.

    I would still measure my actual FG with my hydrometer prior to bottling.

    Do I have that right?
     
  2. Nosybear

    Nosybear Well-Known Member

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    Sounds right to me.
     
  3. Craigerrr

    Craigerrr Well-Known Member

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    Brain is getting antsy to bottle his Kveik fermented NEIPA!
     
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  4. Sunfire96

    Sunfire96 Well-Known Member

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    There's a refractometer calculator on this site for that exact purpose (if OG is known). That's what I use for FG readings
     
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  5. Zambezi Special

    Zambezi Special Well-Known Member

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    Yep, you are right.
    And what Sunfire says ;)
     
  6. BrainYYC

    BrainYYC Active Member

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    Thanks all!
     
  7. BOB357

    BOB357 Well-Known Member

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    A refractometer is just as accurate as a hydrometer, provided it's properly calibrated and the wort correction factor, which is specific for each tool, is calculated by comparing hydrometer and refractometer readings from several worts. Once fermentation has begun and alcohol is present, the OG and current Brix readings need to be entered into a calculator to compensate for the different refractive index of the alcohol and come up with an accurate reading.
    Brewers Friend has a great set of instructions and calculators for using a refractometer. You can also do as you stated and compare readings over 2 or 3 days to determine if fermentation is complete. I use my refractometer throughout the brewing process almost exclusively, and only use a hydrometer occasionally as an accuracy test for the refractometer.
     
  8. Steelyace

    Steelyace New Member

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    I stopped using a hydrometer years ago now. When I switched to a refractometer I compared it to my hydrometer for many many brews and found it to always be the same. So now its easy, just a dropper full to test is all that is needed.
     

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