214 MANAGEMENT OF DAIRY PLANTS 



completely gradually pour on enough alcohol to make 1,000 

 c. c. of tincture and filter. " 



As noted above, a lemon extract may readily be prepared by 

 any manufacturer. The most expensive material used for the 

 preparation of a lemon extract is the alcohol, therefore the 

 manufacturers of extract often prepare cheap terpeneless ex- 

 tracts. It requires at least 80 per cent by volume of alcohol 

 for a lemon extract containing 5 per cent of lemon oil. Deodo- 

 rized or purified alcohol is to be preferred. 



Lemon is not a popular flavor for ice cream, but is used for 

 nearly all water ices and lactos; however, for the manufacture 

 of these, we depend mainly on the juices of the fruit. 



Orange extract is prepared in a similar manner as lemon 

 extract. 



C. Detection of Artificial Extracts. The ice cream maker 

 is seldom capable of making chemical analyses, but there are a 

 few simple tests by which the maker may obtain a fair idea as to 

 the purity of some of the more common extracts. 



If normal acetate of lead solution is added to a sample of 

 vanilla extract a heavy precipitate is formed if the extract is 

 pure. If the extract remains clear, or if only a mere cloudiness 

 is formed, it is conclusive evidence that the extract is artificial. 



Lemon and orange extracts are readily tested by placing a 

 small sample in a test tube; if by adding an equal amount of 

 water a heavy precipitate is formed, then it is an indication 

 that the extract is of good quality. The heavier the precipitate 

 the better the extract. 



The following method by Mitchell is for determination of oil 

 in a lemon or orange extract: "Transfer by a pipette 20 c. c. of 

 the extract to a Babcock milk bottle, add i c. c. of dilute hy- 

 drochloric acid (i : i); add 25 to 28 c. c. of water previously 

 warmed to 60 C. ; mix, and stand in water at 60 for five min- 

 utes; centrifuge for five minutes; fill with warm water to bring 

 the oil into the graduated neck of the flask, and repeat the whirl- 

 ing for two minutes; stand in water at 60 for a few minutes, and 

 read the per cent of oil by volume. Where the oil of lemon is 

 present in amounts over 2 per cent, add to the percentage of oil 



