WINE. 85 



found by deducting the weight of sugar in excess of 0.1 gram per 100 cc from 



tin 1 total residue. In the casr of plastered wines, the potassium sulphate in 

 excess of 0.1 grain is also deducted. 



(2) IN SWEET WINES. 



When the extract content is between 3 and grams per loo cc treat 25 cc 

 of the sample as described under dry wines. When the extract exceeds 6 

 grams per 100 cc, however, the result obtained under (a) is accepted, and no 

 gravimetric determination is attempted. This is because of the serious error 

 connected with drying levulose at high temperature. (The table referred to 

 under (a) was obtained by drying at 75 C. in vacuo.) 



6. Ash. Provisional. 



Proceed as directed under " VI. General Methods," on page 38, employing the 

 residue from the determination of the extract. 



7. Ash-Extract Ratio. Provisional. 



Express results as 1 : x. in which x is the quotient obtained by dividing the 

 percentage of extract by the precentage of ash. 



8. Sodium Chlorid. Provisional. 



Calculate from the chlorin in the ash, determined as directed on page 23, 

 under " III. Inorganic Plant Constituents." 



9. Potassium Sulphate. Provisional. 



Precipitate sulphuric acid directly in 50 cc of wine by means of barium 

 chlorid after acidifying with hydrochloric acid and determine the resulting 

 barium sulphate by the ordinary method. 



10. Phosphoric Acid. Provisional. 



Determine phosphoric acid in the ash by one of the official methods given 

 under "III. Inorganic Plant Constituents," page 22. 



11. Barium and Strontium. Provisional. 



Evaporate to dryness 100 cc of wine, incinerate as directed under the deter- 

 mination of ash " VI. General Methods," page 38, dissolve in dilute hydro- 

 chloric acid, evaporate to dryness, and examine the residue spectroscopically. 

 If barium or strontium be present, fuse with sodium carbonate to decompose 

 silicates,* and determine by precipitation with sulphuric acid. 



12. Total Acids. Provisional. 



Transfer 25 cc of the sample to a beaker, heat to incipient boiling, and in the 

 case of white wines add about 10 drops of a neutral litmus solution and titrate 

 while still hot with tenth-normal sodium hydroxid. With red wines add sodium 

 hydroxid solution until the red color changes to violet and continue to add a 

 few drops at a time until a drop of the mixture placed on delicate red litmus 



a Borgmann. Analyse des Weines, 2d ed., page 143. 



*R. Fresenius, Zts. anal. Chem., 1890, 29: 20, 143 and 413; 1891, 80: 18, 452 and 

 583; 1893, 32: 189 and 312. 



