Am.  Jour  J*harm.  ] 
Sept.,  1882.  I 
Analysis  of  Wine. 
453 
evaporated,  the  residue  taken  u})  with  water,  the  somewliat  turbid 
liquid  cleared  bv  the  addition  of  ])ure  washed  animal  charcoal/  filtered, 
and  the  filtrate,  which  may  amount  in  volume  to  one-tenth  of  the 
original  wine,  treated  cold  with  1'5  to  2  cc.  of  a  20  per  cent,  solution 
of  acetate  of  lime.  A  wine,  which  tested  according  to  Berthelot  and 
Fleurieu's  method  is  found  to  contain  no  free  tartaric  acid,  does  not 
show  the  slightest  turbidity  when  treated  in  the  above  manner.  Wines 
containing  0*05  per  cent,  of  free  tartaric  acid  show  after  a  short  time  a 
•crystalline  separation,  and  after  half  an  hour  a  distinctly  crystalline 
granular  deposit  on  the  sides  and  bottom  of  the  containing  vessel ;  in 
two  hours  the  separation  is  considerable,  after  which  it  does  not  per- 
ceptibly increase.  An  amount  equal  to  O'Ol  per  cent,  gave  in  two 
hours  distinct  crystals  of  tartrate  of  lime.  The  presence,  however,  of 
so  small  a  quantity  of  free  tartaric  acid  is  of  little  consequence  in  judg- 
ing a  wine.  Wines  from  unripe  or  partially  unripe  grapes  contain 
free  tartaric  acid  ;  but  according  to  the  results  of  experiments  on  wines 
from  most  diverse  districts  it  never  exceeds  one-sixth  of  the  non- 
volatile acids  present. 
V.  Estimation  of  Citric  Acid  in  Winc—Qitvia  acid  is  sometimes 
used  as  an  addition  to  the  acid  in  an  excessively  diluted  wine,  either  in 
substance,  or,  if  it  be  desired  to  give  to  the  beverage  at  the  same  time 
body  and  the  appearance  of  old  wine,  in  the  form  of  tamarinds,  in 
which  it  is  present  in  considerable  quantity.  The  estimation  of  citric 
acid  in  wine  has,  therefore,  considerable  interest. 
For  the  detection  of  citric  acid  the  characteristic  behavior  of  its  lime 
salt  can  be  used,  it  separating  in  a  crystalline  form  upon  prolonged 
boiling  of  the  aqueous  solution ;  but  the  citric  acid  mnst  previously  be 
separated  as  much  as  possible  from  other  acids  and  the  special  extract 
•constituents  of  the  wine,  since  citrate  of  lime  remains  dissolved  in  the 
neutral  saline  solutions  of  most  acids.  After  many  unsuccessful  ex- 
j)eriments  the  following  method  was  found  to  give  useful  results. 
100  cc.  of  wine  being  evaporated  to  about  7  cc,  it  is  allowed  to 
•cool  and  then  treated  with  80  per  cent,  alcohol;  after  standing  about 
an  hour  the  undissolved  matter  is  removed  by  filtration,  the  alcohol 
•evaporated  of[*,  water  added  to  bring  the  residue  u])  to  20  cc,  ])art  of 
the  acid  neutralized  with  a  thinnish  milk  of  lime  (red  wine  requires 
^  The  charcoal  nm«t  he  hoiled  with  liydrocliloric  acid  and  wasliod,  so  that 
wliilst  moist  it  sliall  liavc  a  i)orfectly  neutral  reaction,  and  contain  sean^ely 
any  salts,  especially  ])hospliatc 
