GIVE THE SUCROSE CONTENT OF THE TEST SAMPLE . THIS CONCENTRATION IS EXPRESSED IN GRAMS PER LITRE OF WINE , ACCOUNT BEING TAKEN OF THE DILUTIONS THAT MAY HAVE BEEN MADE IN THE COURSE OF CLARIFICATION AND OF THE VOLUME OF THE TEST SAMPLE OF SUGAR SOLUTION BEING EXAMINED .
6 . ASH CONTENT
6.1 . DEFINITION
THE ASH CONTENT IS DEFINED TO BE ALL OF THOSE PRODUCTS REMAINING AFTER IGNITING THE RESIDUE OBTAINED AFTER EVAPORATION OF THE WINE ; THE IGNITION IS CARRIED OUT SUCH THAT ALL OF THE CATIONS ( EXCLUDING AMMONIA ) ARE CONVERTED INTO CARBONATES OR OTHER ANHYDROUS MINERAL SALTS .
6.2 . PRINCIPLE OF THE METHOD
IGNITION OF THE WINE EXTRACT IS CARRIED OUT AT A TEMPERATURE BETWEEN 500 AND 550 C UNTIL COMPLETE OXIDATION OF THE CARBON IS OBTAINED .
THE QUANTITY OF ASH SHOULD BE EXPRESSED IN GRAMS PER LITRE AND BE DETERMINED TO THE NEAREST 0 * 03 G .
6.3 . SINGLE REFERENCE AND USUAL METHOD
PIPETTE 20 ML OF WINE INTO A FLAT-BOTTOMED PLATINIUM DISH OF 70 MM DIAMETER AND 25 MM HEIGHT , PREVIOUSLY TARED ON A BALANCE SENSITIVE TO 0 * 1 MG . CAREFULLY EVAPORATE THE LIQUID , PREFERABLY ON A WATERBATH . HEAT THE RESIDUE GENTLY ON A HOT PLATE OR UNDER AN INFRARED EVAPORATOR ( FOR APPROXIMATELY 30 MINUTES ) UNTIL CARBONIZATION COMMENCES . WHEN EVAPORATION HAS CEASED , PLACE THE DISH IN AN ELECTRIC FURNACE WITH CONTINUOUS VENTILATION AND HEATED TO 525 MORE OR LESS 25 C . WITHDRAW THE DISH AFTER CARBONIZATION ( NORMALLY FIVE MINUTES ) , ADD 5 ML OF WATER , EVAPORATE THE MIXTURE ON A WATERBATH OR UNDER AN EVAPORATOR AND AGAIN HEAT THE RESIDUE TO 525 C .
IF COMBUSTION ( OXIDATION ) OF CABONIZED PARTICLES IS NOT COMPLETE AFTER 15 MINUTES , REPEAT THE WASHING OPERATION , EVAPORATION OF THE WATER AND RE-IGNITION .
FOR WINES WITH A HIGH SUGAR CONTENT , ADD IF NECESSARY A FEW DROPS OF PURE VEGETABLE OIL TO THE EXTRACT BEFORE THE FIRST ASHING TO PREVENT EXCESSIVE FOAMING . IN THIS CASE PROLONG THE IGNITION FOR A FURTHER 15 MINUTES .
WEIGH THE DISH AFTER COOLING IT IN A DESICCATOR . THE WEIGHT OF THE ASH IS MULTIPLIED BY 50 AND REPORTED AS GRAMS PER LITRE .
7 . ALKALINITY OF THE ASH
7.1 . DEFINITIONS
TOTAL ALKALINITY OF THE ASH IS DEFINED AS THE SUM OF CATIONS OTHER THAN AMMONIUM COMBINED WITH THE ORGANIC ACIDS OF THE WINE .
PARTIAL ALKALINITY OF THE ASH IS THE ALKALINITY FROM THE CARBONATES , OXIDES AND SILICATES ONLY IN THE ASH .
ALKALINITY PER GRAM OF ASH ( OR ALKALINITY VALUE ) IS CALCULATED BY DIVIDING THE TOTAL ALKALINITY EXPRESSED IN GRAMS OF POTASSIUM CARBONATE BY THE WEIGHT OF THE ASH .
7.2 . PRINCIPLE OF METHODS
( A ) TOTAL ALKALINITY
TREATMENT WITH EXCESS SULPHURIC ACID AND BACK TITRATION OF THE EXCESS USING METHYL ORANGE AS INDICATOR .
( B ) PARTIAL ALKALINITY