CONDENSED BurreERMILK 181 
If the buttermilk comes from sweet cream butter or from 
neutralized cream churnings, it is usually not sufficiently sour 
for ready handling and rapid evaporation. It therefore should 
be allowed to ripen before it is used. For this purpose it is held 
in wooden storage tanks for one or more days, where it auto- 
matically develops acidity due to the lactic acid bacteria with 
which it is usually teeming. For most satisfactory operation the 
buttermilk should have an acidity of approximately .6 per cent. 
In some cases it may be necessary to inoculate it with lactic 
acid starter in order to insure the desired acid development. 
Heating the Buttermilk —From the ripening tanks the but- 
termilk is drawn or pumped into the hot wells, where steam is 
turned direct into it until the temperature is raised to the boiling 
point. This method of heating also keeps it agitated and pre- 
vents the copious settling of the curd. 
Condensing.—From the hot wells the boiling-hot buttermilk 
is drawn into the vacuum pan. ‘The buttermilk is preferably 
drawn from the bottom of the hot weils, so as te continuously 
remove a portion of the settling curd. The buttermilk will 
drop some of its curd in the hot wells. The operation of the vacu- 
um pan for buttermilk is the same as for milk. For general 
directions the reader is referred to Chapter Von ‘*Condensing.”’ 
The first pans used for condensing buttermilk were tin 
coated on the inside and had tinned copper coils. so as to mini- 
mize the action of the acid on the copper. The tin coating was 
of very short duration, however, especially that on the coils, so 
that it was found impractical and too costly to use tinned vac- 
uum pans. The pans now in use are not tinned. 
In the condensing of a thick and sluggish liquid, such as 
-buttermilk, it is of the greatest importance that the coil arrange- 
ment in the vacuum pan be such as to insure maximum circula- 
tion of the milk, otherwise the buttermilk is incapable to absorb 
the heat fast enough and to expose enough surface to evapora- 
tion, to make possible rapid concentration, the buttermilk fails 
to freely boil up, it slugeishly bubbles in the bottom of the pan, 
evaporation is slow, the capacity of the pan is greatly reduced, 
and the cost of manufacture is increased. For detailed descrip- 
tion of the proper coil arrangement see Chapter V on “Descerip- 
tion of Vaeuum Pan.” 
