A refractometer measures how much light bends as it passes through a liquid. n = velocity of light in a vacuum / velocity of light in medium
Can a refractometer be used to check nutrient density in plant sap?
From the Real Food Campaign Website: Pure water at a specific temperature will bend light at a specific angle. A wide variety of biological substances can increase solution density, and thus cause light to refract (bend) more as it passes through a watery medium: 1. dissolved minerals (salts, acids, alkali) 2. carbohydrates (simple sugars) 3. amino acids (proteins) 4. lipids (special case: oil & water don't mix; form thin films) 5. almost any molecule with covalent bonding 6. very large suspended particles (colloids)
BRIX measures the percent solids (TSS) in a given weight of plant juice‚ nothing more‚ nothing less. BRIX is often expressed as the percentage of sucrose. However, the "sucrose" can vary widely. BRIX is actually a sum of the pounds of sucrose, fructose, vitamins, minerals, amino acids, proteins, hormones, and other solids in one hundred pounds of plant juice.