346 THE ANALYST.

THE COMPOSITION OF MALT VINEGAR.

BY EDWARD RUSSELL, B.Sc., F.I.C., AND T. R. HODGSON, &LA., F.I.C.

(Rend at the J l e e t i ? ~ ~ , J U ~ W 1, 1910.)

IN the recent interesting memorandum on the character and composition of vinegar published by the Local Government Board (ANALYST, 1909, 34, 431), figures on the general analysis and methods of determining the purity of malt vinegar are sub- mitted and discussed. I t occurred to us that it would be a convenient opportunity for a further examination of the question of the composition of malt vinegar by nieans of an additional number of analyses of similar specimens, and by a general review of the preceding work in this subject, in order to see if it were possible to advance at all in the direction of suggesting a standard for this important substance.

The Public Analyst at the present time is greatly handicapped by the fact that there is no legal definition of malt vinegar, and, owing to this, much so-called malt vinegar is regularly placed on the market which by its unsatisfactory character seriously affects the sale and repute of the genuine article. In many cases no malt whatever has entered into the composition of the vinegar, and the liquid is dilute acetic acid with some colouring matter.

The analyses of malt vinegars by different observers show very varied results. We will first quote those given by Dr. Hamill in the Local Government Board Memorandum :

Sp. gr. ... ... 1016.3 1018.5 1017.7 1017.5 1017.0 1015.1 Acetic acid, per cent. 6.00 5.85 5.46 5.40 5-19 4.44 Total solids, per cent. 1-55 2.58 2-22 2.76 2.13 2.22 Ash, per cent. ... 0.36 0.29 0.35 0.30 0.37 0.26 Phosphates (as P,O,),

per cent. ... ... 0-07 0.14 0.08 0.07 0.10 0.05

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THE ANALYST, 347

Reference to the work of the following observers shows that there is great variation in the results recorded :

Ratcliffe (ANALYST, 1907, 32, 85) gives the results of analysis of eleven samples as sent out by the manufacturers. Allen (“ Commercial Organic Analysis,” p. 470) quotes figures for genuine malt vinegar. Wynter Blyth ((( Foods : their Composition and Analysis ”) records a somewhat more extended analysis, but apparently considers that the results of analysis are invariable. Hehner (ANALYST, 1891, 16, 82) has given the analysis of samples of malt vinegar, which show great variations in the amounts of the different constituents. Fairley (ibid. , 1909, 34, 515) records a case in which the amount of phosphates was as low as 0.04 per cent.

It is noticeable, on comparing the results of the work of these authorities, that there are wide variations in the composition of undoubtedly genuine malt vinegars -as wide, indeed, in certain cases as the variations between some genuine and adulterated samples. Any standard proposed, therefore, must be very low, even as compared with the composition of a vinegar of average quality.

We record below the results of analysis of thirteen samples of vinegar, of which A to I are undoubtedly genuine malt vinegars, K is a sample sold as malt vinegar, but prepared without the uge of malt,” P and Q are samples of wood vinegar, and R is a sample taken in Bristol under the Sale of Foods and Drugs Acts, and supposed to be malt vinegar, but obviously of a very dubious character :

A. 1021.6

5 2 8 3.15

B. 1018.0 6.15 1.47

C. 1019.3 4-50 2-70

D. 1016-3 5.52 1.71

E. 1014.4 3.96 2-38

F. 1013.7 3-85 2.26

Sp. gr. ... ... Acetic acid, per cent. Total solids, her cent. Original solids, per

cent. ... ...

Alkalinity of ash (as Ii20), per cent. ... Phosphates (as P,O,),

per cent. ... ...

Ash, per cent. ... 11-79 0.35

11.89 0.42

11.20 0.60

9.54 0.33

8-80 0.19

8.92 0.18

0.032 0.030 0,017 0,016 0.039 0.037

0.072 0.078 0.051 0.076 0.092 0.078

G. Sp. gr. ... ... 1021.3 Acetic acid, per cent. 5-76 Total solids, per cent. 3-06 Original solids, per

cent. ... ... 11-16 Ash, per cent. ... 0.51 Alkalinity of ash (as

Phosphates (as P,O,), K,O), per cent. ... 0.040

per cent. ... 0-047

H. 1022.1 6.36 2.97

I. 1018.4 4.68 2.57

I<. 1017.0 4.80 2.36

P. 1012.08

2.20 0.172

Q. 1012.4 2.30 0.431

R. 1013.99 2.65 0.691

13-41 0.57

10.25 0.53

10.04 0.23

8.061 0.041

7.758 0.034

10.887 0.063

0.040 0.035 0.014 0.022 0.031 0 -040

0.075 0.075 0.020 Nil Nil Nil

We will now consider the analytical data given in the above tables. We have in the total solids of the malt vinegars very slight variations (1.47 to 3.15 per cent.), but these are very markedly higher than the amount of solids shown by the wood vinegars. The acetic acid varies from 3.85 to 6.36 per cent. ; but as this may be easily increased by the addition of acetic acid, obtained from other sources, it is of

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348 THE ANALYST.

very little assistance in the determination of the genuineness or otherwise of the vinegar. The ash varies from 0.18 to 0.60 per cent., and, as would be expected, is markedly higher than that of wood vinegar. The phosphates vary from 0.047 to 0.092 per cent. in the case of malt. vinegars, and are absent altogether from the wood vinegars. We would point out the close resemblance in the analysis of the sample K, which contains no malt, to the analyses of the genuine samples, and that the only distinguishing feature is the comparatively small amount of phosphates present. The alkalinity of the ash, using methyl orange as an indicator, appears to be of little if any value in deciding between malt and wood vinegar.

We also examined the statement of Brode and Lange (Adwit. Kuzserl. Gesundamte, 1907, 30, 54), that in the estimation of the solids in vinegar a certain proportion of the acetic acid, varying from 0.08 to 0-2 per cent., is obstinately retained by the residue, and that it is necessary, if accurate results are to be obtained, to measure this amount by subsequent titration. We evaporated 100 C.C.

of the vinegar to dryness, and redissolved and titrated the acetic acid (Column A below). We then evaporated a further portion, redissolved the residue and evaporated again, and titrated the remaining acetic acid (Column B), and finally a third portion was evaporated three times (Column C).

A. B. C. D. E. k'. G . H. I . 1;. Per Per Per Per Per Per Per Per Per Per

Cent. Cent. Cent. Cent. Cent. Cent. Cent. Cent. Cent. Cent. column A .... 0.19 0.17 0.21 0.20 0.15 0.17 0.15 0.22 0.18 0.18

,, B ... 0.01 0.08 0.012 0-083 0.004 0.02 0.007 0.01 0.005 0.03 y y C ... Nil 0,005 Nil Nil Nil Nil Nil Nil Nil Nil

AS will be seen, the statement is correct in so far as a portion of the acetic acid does remain in the solid residue ; but as this is entirely removed after three evaporations, it is scarcely necessary to redissolve the solids and titrate the acetic acid.

We would point out that in the United States of America the standard for iiialt vinegar is-

Acetic acid ... ... ... not less than 4.0 per cent. Total solids . . . ... * . * $ 9 99 2.0 9 9

Ash ... ... ,7 I 7 0.2 ?,

Phosphates (as'P,O,)' * ' ... 3 9 ,, 0.009 2 ,

As showing the futility of the above, we would point out that the sample K would easily pass the U.S.A. standard, and yet it is admittedly made from substances other than malt.

Finally, we consider that the differentiation between malt and wood vinegar is so obvious that no standard is necessary; but we do consider that the following standard for malt vinegar might be suggested :

Acetic acid . . . ... not less than 3-5 per cent. Phosphates (as P20i)' . . . ) 9 9 , 0.05 9 7

THE CITY LABORATORY, BEISTOL.

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