13 



were supplemented hy a further letter submitting a modified method for the deter- 

 mination <>f volatile and fixed acids. The subjects reported upon included the deter- 

 mination of u'lycerol in wines, the examination of natural coloring matter in wines, 

 and the determination of total, fixed, and volatile acids; besides which there was 

 submitted a special report on the determination of reducing sugars, by R. M. West. 

 Th.-.- pa pi-rs, together with the letter of instructions and a statement of the modified 

 methods which were studied, constitute the report of referee. 



INSTRUCTIONS. 



FEBRUARY 28, 1908. 

 Di.\i:Sii;: I wnd you herewith an outline of methods for analysis of wine. It is my 



desire that you subject these methods t careful investigation, using for the purpose 

 samples of your o\vn mlliTtion. In general the plan of work for this year will be to 

 allow each collaborator Considerable latitude as to how he is to conduct his work. ' In 

 ..flier word.-, you are requested to make an independent investigation of all or as many 

 of ihe-e methods as possible and prepare a paper giving your results and criticisms. 



i.il attention i, directed to the following points: 



(\) The change to 20 C. as the standard temperature for specific gravity and alco- 

 hol determinations. 



(2) t'niformity of terms in which to express results, considering especially (a) the 



i e\pn->.-in-.' all results when possible in grams per 100 cc of sample, (6)*the idea 



Lpremng total, volatile, and li\-d acids as cubic centimeters of normal acid in 



>le. 



1 tnpr\ emeu?.- iii the method for detenniniiig glycerol. 



A thorough trial <-f the new method of determining volatile and fixed acids 

 (see below). A drawing and a description of the apparatus used are given in this 



conne 



:n of the uranium method for determining phosphoric acid * *. 



:h'- -cheme f, -r \amination of the natural coloring matter 

 of \\in.-s, n-ini: i'..r the purpose samples of the red-wine class. 



(7) A .Tiiici.-m ..f the method for detecting lluorids ami the method for determin- 



.Iphun.us . 

 - An inxe.-iiuMiion and . -niicism ..f any of the other provisional methods for wines. 



perially the \olumetric metho<l for determining reducing sugars. 

 It is desired that the i .ur in\ est i-jat ions be reported in full, showing all 



important numerical data. ConcluriODB, and reo.mmendat ions. * * * 



PKOI'OSKI> MKTIK i - fOB MM W I I I: M 1 \ A I H > \ ol TOTAL, VOLATILE, AND FIXED ACIDS. 



Total acids." 



.inure 10 cc of the sample into a 300 cc flask, add 100 to 200 cc of recently boiled 

 distilled water, according t<> the color of the wine, and boil three minutes under a 

 retlnv condenser. Alter -.... liny add '1 >r :i drops of phenolphthalein and titrate with 

 tenth-normal sodium hydmxid. Kx press the result for total acids as cubic centi- 

 mei.-r- '.i n.irmal K*ld in l" (l CC of the wine. 



\'<>la'ii> amlji.rfil acids. 



The apparan: 1 con<i-i< of a cvlindrical flat bottomed flask of about 300 cc 



capait\. provided with an elongated wide neck. Into the neck of this flask is fitted 

 by mean- of a -hort .- -tion of thick rubber tubing a cylindrical shaped flask in the 

 but torn of which is a small opening leading inward through a siphon-shaped tube 

 bent back upon it-elf ami terminating at a point close to the bottom. The inner flask 

 IB O mnected to a condenser by means of a bent tube and safety bulb. In the stopper 

 i- al-o tilted a small funnel provided with a glass stop-cock. The distillate from the 

 condenser i- received in a cylindrical graduate. 



Pour 100 cc of recently boiled distilled water into the larger flask, tightly fit the 



smaller tlask into the wide neck, run in 10 cc of wine through the funnel, rinse out the 



funnel with a little water, close the stop-cock and heat the water to boiling. The steam 



nir through the siphon tube and through the wine carries out the volatile acids. 



When 50 cc of distillate have passed over, empty the graduate and continue the 



Pierre Breteau, Guide pratique des falsifications et alterations des substances 

 alimentaires, p. 318. 



