ML OF MILK OF LIME ( 120 G OF CAO PER LITRE ) . THE COLOURING MATTER OF THE WINE SHOULD BE CHANGED BY THE ALKALINITY . IN THE CASE OF VERY ACID , SOUR WINES , ETC . , ADD THE LIME UNTIL THE WINE IS CLEARLY ALKALINE TO PHENOLPHTHALEIN USED EXTERNALLY . ADD , IF NECESSARY , SOME INERT POROUS MATTER AND A DROP OF AN AQUEOUS SOLUTION , OF ONE PART PER 100 OF WATER-SOLUBLE SILICONE TO PREVENT FROTHING . COLLECT THE DISTILLATE IN THE SAME FLASK AS THAT USED FOR MEASURING OUT THE WINE , AND INTO WHICH HAS BEEN PLACED 10 ML OF DISTILLED WATER .
DISTILL AT LEAST 200 ML . SHAKE THE FLASK AND MAKE UP TO THE MARK AT THE SAME INITIAL TEMPERATURE ( TO WITHIN 5* C ) .
2 . MEASUREMENT OF SPECIFIC GRAVITY OF THE DISTILLATE : POUR THE DISTILLATE INTO A GLASS CYLINDER STANDING ON A LEVEL SURFACE OF 36 MM INTERNAL DIAMETER AND 320 MM HEIGHT . KEEP THE CYLINDER VERTICAL . PLACE A THERMOMETER AND HYDROMETER IN THE CYLINDER . READ THE THERMOMETER ONE MINUTE AFTER SHAKING , SO ENSURING EQUILIBRIUM TEMPERATURE OF CYLINDER , THERMOMETER , HYDROMETER AND DISTILLATE HAS BEEN REACHED . WITHDRAW THE THERMOMETER AND READ THE APPARENT DEGREE OF ALCOHOLIC STRENGTH AFTER ONE MINUTE . TAKE AT LEAST THREE READINGS USING A MAGNIFYING GLASS . CORRECT THE APPARENT DEGREE MEASURED AT T* C FOR THE EFFECT OF THE TEMPERATURE WITH THE FOLLOWING TABLE .
WHEN MAKING THE OBSERVATIONS THE TEMPERATURE SHOULD NOT DIFFER FROM AMBIENT BY MORE THAN 5* C . IF A GREATER DIFFERENCE IS OBSERVED IT MAY BE AVOIDED BY USING A VACUUM FLASK .
SECOND USUAL METHOD
DENSIMETRY BY THE HYDROSTATIC BALANCE
THE DISTILLATION APPARATUS AND ITS METHOD OF OPERATION ARE THE SAME AS FOR THE FIRST USUAL METHOD .
THE APPARATUS , THE CALIBRATION OF THE FLOAT AND THE PROCEDURE HAVE BEEN DESCRIBED IN CONNECTION WITH THE MEASUREMENT OF THE DENSITY , BUT THE MEASUREMENT OF DENSITY OF THE DISTILLATE MUST BE MORE ACCURATE THAN THAT OF WINE . IT SHOULD BE OBTAINED AT LEAST TO THE NEAREST 5 BY 10-5 G/ML . IN ORDER TO ACHIEVE THIS RESULT ONE SHOULD USE A FLOAT OF AT LEAST 50 ML AND TAKE ALL NECESSARY PRECAUTIONS TO AVOID ANY EVAPORATION OF THE ALCOHOL AND TO KNOW THE TEMPERATURE , T* C , OF THE DISTILLATE TO AT LEAST THE NEAREST 0.1* C .
THE FORMULAE FOR THE CALCULATION HAVE ALSO BEEN MENTIONED ALREADY .
KNOWING PT AT T* C , ONE DETERMINES THE ALCOHOLOMETRIC TITRE BY MEANS OF ONE OF THE DENSITY TABLES , WHICH ONE SELECTS ACCORDING TO THE NATURE OF THE GLASS USED IN THE FLOAT , FOLLOWING THE SAME INTERPOLATION PROCEDURE AS FOR THE REFERENCE METHOD .
2.5 . SUPPLEMENT TO THE REFERENCE METHOD FOR THE MEASUREMENT OF THE DENSITY OF THE DISTILLATE
MEASUREMENT BY PYCNOMETER ON SINGLE-PAN BALANCE
PRINCIPLE
THE PRINCIPLE OF THE METHOD OF DETERMINING