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Brix Book - Hand Refractometers |
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Page 8 of 35
HAND REFRACTOMETERS
Professor Brix’s hydrometer worked, but it was cumbersome and required a tall graduate of juice to actually conduct the measure. This was OK for the vineyard wine cellar, but a nuisance to the grower in the field who wished to squeeze perhaps a single growing grape to judge its potential quality.
A refractometer is an optical device that takes advantage of the fact that light passing through a liquid bends or refracts. Thicker, i.e., more dense, liquids refract more. Solids dissolved in a liquid will cause it to exhibit a refractive index in direct relation to the amount of solids. A refractometer substitutes a calibrated prism and an etched screen for the liquid. Refraction is extremely exact and no modern chemist wishes to be without a refractometer.
Table model refraction measuring devices date back to the 1600’s. Although lost to antiquity, it appears that some scientist, or perhaps artisan, developed a workable portable model sometime in the latter 1800’s. By the 1920’s, rather bulky "hand" models were in use in many vineyards.
Although complicated in construction, a modern hand refractometer is extremely easy to use.
Today’s hand refractometer we are discussing looks almost like a small 5" or 6" long telescope, but it has a prism at the end opposite the viewfinder. A calibrated hand refractometer allows determination of a reading or degree brix when you place a drop of juice on the prism and flatten it with the attached cover plate.
While widespread farming use (other than vineyards) traces back only some 20+ years, other (industrial & commercial) uses of hand refractometers are decades older. The devices are simple, accurate, durable, and easily carried. A refractometer's initial expense seems lessened as you use one and realize it will last as long as a pair of fine binoculars. It may even become a much-sought heirloom for family members. |
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