Kern ora series analogue refractometers kern ora 3sa the kern ora 3sa refractometer measures the concentration of salt solutions by measuring their refractive index it enables you to determine the salt content in foodstuffs this is often used in the production and cooking of sauces brines for pastries the production of brines eg brine matured cheese marinades for meat and the preparation of seafoodthe kern ora 3sa is a universal maintenance free analogue manual refractometer its p