Using a Brix Refractometer

Using a Brix Refractometer

The scale of the Brix Refractometer is designed to measure the level of sucrose in a solution; however, Brix values can be correlated to IgG in colostrum and solids in milk. These units are available in both optical and digital designs.



Your refractometer must be calibrated before the first use and every so often, so you can be confident that you are getting an accurate reading. Be sure to follow any specific instructions included with your unit, but in general calibration can be done by applying a drop of distilled water to the prism area. Make any adjustments needed so that the unit gives a Brix reading of 0.



Studies have shown the Brix reading to be positively correlated to IgG content of colostrum. A Brix value of 22% corresponds to 50 mg/mL. Therefore, any colostrum with a Brix reading of 22% or greater is considered to be high quality colostrum. 



A brix refractometer can also be used to determine the % solids of milk that is to be fed to calves. The Brix reading of milk +2 is a close estimation of the total percent solids. Naturally whole milk is 12-13% solids, however, waste milk can often vary in solids content due to a variety of factors. Assessing the solids level of milk can be very beneficial in calculating the amount of milk replacer that might need to be added to make a nutritionally consistent final milk solution.


Written by: Mariah Gull, M.S.


Image credit: Journal of Dairy Science (

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