158 REpoRT OF THE CHEMIST OF THE 
TABLE X V.—PERCENTAGE OF Frxep Acip as Mauic Acip IN APPLE 
Juice AT DIFFERENT PERIODS OF FERMENTATION. 
Dube. of | Fresh. | 1 mo. | 6 mos.| 7 mos.| 8 mos.| 9 mos.| 10 mos.| 15 mos.| 24 mos.| 72 mos. 
Per ct. |Per ct:|Per ct.|Per ct.|Per ct.|Per ct.| Per ct. | Per ct.| Per ct. | Per ct 
1 ra teaPereeucee 0.52 | 0.50 | 0.46 | 0.42 | 0.44 | 0.24 -02 0.02 0.01 
7d SoG te Rotor e 0.51 | 0.48 | 0.39 | 0.39 | 0.09 | 0.09 0.04 0.01 0.02 —— 
3 0.49 | 0.48 | 0.36 | 0.34 | 0.11 | 0.08 0.03 0.01 0.02 —— 
Beer vasie Siaoie 0.63 | 0.63 | 0.41 | 0.41 | 0.18 | 0.09 0.05 0.10 0.07 = 
Otte eee 0.66 | 0.65 | 0.48 | 0.49 | 0.10 | 0.10 0.08 0.10 0.01 —_ 
(seo are epee 0.62 | 0.62 | 0.47 | 0.47 | 0.07 | 0.09 0.10 0.02 0.03 0.04 
Up ae TE 059" O53" 0-387) 170227 | 0.06 | 0206 0.05 0.03 0.01 — 
Saeco 0.47 | 0.47 | 0.41 | 0.29 | 0.08 | 0.07 0.06 0.02 0.01 —- 
OR ier so shes 0.51 | 0.50 | 0.40 | 0.32 | 0.11 | 0.09 0.06 0.05 0.05 — 
NOR axtae i 6 oe 0.41 | 0.39 | 0.35 | 0.13 | 0.06 | 0.07 | 0.09 0.03 0.03 — 
1 a ahcoee aie [OND SEP et 0) TO) S| || 0.09 0.10 0.02 0.01 
DZ rekon 0.59 | —— | 0.41 | —— | —— | — | ——— 0.11 0.02 0.00 
Se toareiatte, dicuss oh || OES | | | 0.18 0.14 0.02 0.00 
14 0.59 | —— | 0.438 | —— | —— | —— — 0.16 0.05 — 
1s See er | 0.59 | —— | 0.41 | —— | —— | —— —- 0.09 0.01 —— 
16 |} 0.59 | —— | 0.39 0.16 0.02 0.01 — 
dion teiviasone'ste!= | OAT OL | OG 0.13 == SS Ss 
| 
Average...| 0.55 | 0.53 | 0.39 | 0.35 | 0.13 | 0.10 0.08 0.06 0.02 — 
In studying the data contained in this table, we notice the 
following points: 
(1) In most cases very little change in the amount of fixed 
acid occurs during the first month. 
(2) Nearly one-third of the fixed acid disappeared in six 
months; between the sixth and seventh months some more malic 
acid disappeared, but between the seventh and eighth months, in 
most cases, the decrease of fixed acid was very marked. 
(8) The period when the malice acid decreased most rapidly 
was after the alcoholic fermentation had been completed and 
before the acetic fermentation had become very active. 
(4) As a rule, when the cider had become good vinegar, there 
remained only a trace of fixed acid. In the case of some old 
vinegars, all fixed acid disappeared. 
The decrease of malic acid under these circumstances is un- 
doubtedly the result of the action of some bacterial ferment. 
It is? well known that malic acid and some of its salts undergo 
destructive fermentation, but, so far as we have been able to 
learn, no one has worked out the details of this phenomenon in 
relation to cider vinegar. Seifert’? has shown that the decrease 
*Emmerling. Die Zersetzung Stickstofffrier organischer Substanzen durch 
Bakterein, pp. 128-9 (1902). 
10Bied, Centr., 33: 488 (1904). 
