Determination of antifreeze mixing ratios The measurement of antifreeze concentration and amount of freezing point depression is made possible with in-line refractometers by SCHMIDT + HAENSCH. Our in-line refractometers can measure the mixing ratio which makes it easy to ensure frost resistance of mixtures made out of water with ethylene glycol, propylene glycol or brand names like Glysantin. Our process refractometers are fully in line with your production and integrate seamlessly while measuring concetration without loss of product.