84 Condensed Milk and Milk Powder 



sweetened condensed milk and the density can be readily determ- 

 ined by means of a hydrometer. Beaume hydrometers, registering 

 from i to 15 degrees B., are generally used. As it is important that 

 the determinations be accurate, the hydrometer should be sensitive 

 and its scale should be subdivided into tenth degrees. The batch 

 should be "struck" at a uniform temperature, say 120 degrees F., 

 so as to avoid misleading readings of the hydrometer. A difference 

 of a few tenths degrees Beaume affects the behavior of 

 the evaporated milk in the sterilizer very appreciably. If the 

 density is too great the product may badly curdle during steriliza- 

 tion. If the density is too low the evaporated milk may be below 

 the legal standard. It is advisable for the operator to use a pail of 

 water of the proper temperature, when he strikes the batch, so that 

 he can adjust the temperature of the milk in the hydrometer jar 

 readily and quickly, and need not depend entirely on the temperature 

 of the milk in the pan, which may change several degrees while he is 

 engaged in the operation of striking. 



While the Beaume hydrometers should be used at the tem- 

 perature for which they are graduated, which is 60 degrees F., 

 they answer all practical purposes at any other temperature; at 120 

 degrees F. for instance. The chief essential is to take the reading 

 at some uniform and definite temperature and read the Beaume at 

 that same temperature in the case of every batch. In that way the 

 results are comparable. The operator soon learns that at a given 

 temperature the evaporated milk of proper density shows a certain 

 Beaume reading. When the reading is higher or lower, the milk 

 has either been condensed too much or not enough. 



The same formula, however, cannot be used under all condi- 

 tions. No rule-of-thumb method of determining the density can 

 therefore be established. Aside from the degree of condensation, 

 the specific gravity of the milk varies with locality, season of year, 

 quality of milk, etc. This means that what is the proper Beaume 

 reading in one locality, or at one season in the same locality, may be 

 entirely wrong in another locality or at other seasons in the same 

 locality. If uniformity in the density and behavior of the batches 

 of evaporated milk is to be secured throughout the year, the operator 

 must watch the behavior of his milk from day to day and from 

 season to season and he must modify the Beaume reading in ac- 



