TO CALCULATE THE VOLUME OF THE PYCNOMETER AT 20 C . ( SEE O.J . N L 360 OF 22 . 12 . 78 )
PROCEDURE
CAREFULLY FILL THE PYCNOMETER WITH THE LIQUID AT AMBIENT TEMPERATURE AND PLACE IN THE THERMALLY INSULATED ENCLOSURE ; SHAKE THE LIQUID TWO OR THREE TIMES BY INVERTING THE CONTAINER UNTIL THE TEMPERATURE READING ON THE THERMOMETER IS CONSTANT . ACCURATELY ADJUST THE LEVEL TO THE UPPER RIM OF THE LATERAL TUBE . WIPE THE LATERAL TUBE DRY , PUT THE RECEIVER PLUG ON AND MEASURE THE TEMPERATURE T C WITH THE SAME CARE AS PREVIOUSLY ; CAREFULLY WIPE THE PYCNOMETER DRY AND THEN WEIGH , P * BEING THE WEIGHT TO GIVE EQUILIBRIUM .
THE DIFFERENCE BETWEEN THE CORRECTED TARE AND THE WEIGHT RECORDED GIVES THE MASSES OF THE LIQUID IN THE APPARATUS ( CORRECTED FOR BUOYANCY OF THE AIR ) .
CALCULATE THE APPARENT DENSITY AT T C BY DIVIDING THIS MASS BY THE VOLUME AT 20 C , AND THE APPARENT SPECIFIC GRAVITY DT20 BY DIVIDING THIS SAME MASS BY THE MASS OF THE WATER CONTAINED AT 20 C IN THE PYCNOMETER .
1 . CORRECTION FOR TEMPERATURE
CORRECT * T AND DT20 USING ONE OF THE FOLLOWING CORRECTION TABLES IN ACCORDANCE WITH THE NATURE OF THE LIQUID MEASURED : DRY WINE ( TABLE II ) , NATURAL OR CONCENTRATED MUST ( TABLE III ) , SWEET WINE ( TABLE IV ) , ALCOHOL-FREE RESIDUE ( WINE FREED OF ALCOHOL BY DISTILLATION AND THE RESIDUE FROM THE DISTILLATION MADE UP TO THE ORIGINAL VOLUME ) ( TABLE II ) . IN THE COMPILATION OF THESE TABLES THE EXPANSION OF THE LIQUIDS AND OF THE CONTAINER BETWEEN T AND 20 C HAS BEEN TAKEN INTO ACCOUNT .
2 . CORRECTIONS MADE NECESSARY BY THE PRESENCE OF PRESERVATIVES
THE DENSITY MUST SUBSEQUENTLY BE CORRECTED FOR THE EFFECT OF SULPHUR DIOXIDE BY USING THE FORMULA : ( SEE O.J . )
TABLE II
TEMPERATURE CORRECTIONS C TO THE DENSITY OF DRY WINES AND OF ALCOHOL FREE DRY WINES MEASURED IN A PYREX GLASS PYCNOMETER AT T C TO RELATE THE RESULT TO 20 C ( SEE O.J . )
TABLE III
TEMPERATURE CORRECTIONS C TO THE DENSITY OF NATURAL MUSTS AND OF CONCENTRATED MUSTS MEASURED WITH A PYREX GLASS PYCNOMETER OR HYDROMETER TO RELATE THE RESULT TO 20 C ( SEE O.J . )
TABLE IV
TEMPERATURE CORRECTIONS C TO THE DENSITY OF WINES OF 13 % VOL OR MORE MEASURED WITH A PYREX GLASS PYCNOMETER AT T C TO RELATE THE RESULT TO 20 C ( SEE O.J . )
NUMERICAL EXAMPLES
THE SETTING-UP OF PYCNOMETER CONSTANTS ( SEE O.J . )
DETERMINATION OF THE DENSITY OF A DRY WINE ( SEE O.J . )
1.4 . FIRST USUAL METHOD
MEASUREMENT BY A HYDROMETER _ APPARATUS
THE APPARATUS USED SHALL COMPLY WITH THE FOLLOWING CHARACTERISTICS .
THE APPARATUS SHALL HAVE A CYLINDRICAL BULB , A STEM OF CIRCULAR SECTION OF MINIMUM DIAMETER 8 MM