6 
BULLETIN 399, U. S. DEPARTMENT OF AGRICULTURE. 
attached to the distilling apparatus. When the gauge indicates 
sufficient diminution in the pressure, steam is admitted into the 
jacket of the retort. The thin mixture of water and peel begins 
to boil almost immediately, and the water vapors passing into the 
condenser carry the oil with them. Here the vapors are condensed 
and the distillate is collected in the receiver. The oil being fighter 
than water floats on the surface and can easily be separated. The 
peel is exhausted in about 30 minutes. Steam can also be admitted 
directly into the retort and the oil extracted under diminished pres- 
sure by direct steam. The oil obtained by vacuum distillation was 
light lemon yellow in color and possessed a pleasing orange odor and 
the characteristic aro- 
matic orange taste. 
The oil obtained by 
direct steam distilla- 
tion is not of as good 
quality as that ob- 
tained when the heat 
is applied by means 
of the jacket. The 
best results, however, 
were obtained when 
both jacket heat and 
direct steam were 
used simultaneously. 
The oil obtained was 
macerated with 2 
per cent of its weight 
of fresh unextracted 
peel and then filtered. 
Thus treated, the oil 
had a lemon -yellow 
color with a slight 
tinge of brown. It 
had an excellent orange odor and the characteristic aromatic orange 
taste. Apparently the odor-bearing and flavoring constituents are all 
present and by the method described a fair grade of orange oil can be 
prepared. 
PRESSED OIL. 
Pressed orange oil is generally understood to mean the oil which 
is pressed from the peel by hand. Where labor is cheap such a 
method of extraction is economically possible, but where labor is 
relatively costly this method can not be used. Accordingly, methods 
were worked out for applying heavy pressure without any great 
outlay of money for hydraulic presses. 
Fig. 3.— Experimental vacuum still used in extracting orange oil: A, 
Still; B, condenser; C, receiver. 
