Rensselaer Republican, Volume 14, Number 2, Rensselaer, Jasper County, 29 September 1881 — How Condensed Milk is Made. [ARTICLE]

How Condensed Milk is Made.

The manufacture of condensed milk is thus described in the Scientific American: .When.the milk is brought into the factpry it is carefully strained, placed in cans of palls, which are put into a tank of water kept hot by steam colls. When hot it is trarfsferred to larger steam-heated open vessels and quickly brought to a boil. This perliminafy heating aud boiling has for its objects the explosion of the gases of the milk, which would cause it to foam in the vacuum-pan, and also to add to the keeping quality of the milk by destroying the mould germs. A second straining follows, after which the milk is transferred to a vacuum-pan, where, at a temperature below 160 degrees Fahrlheit, it boils and is rapidly concentrated to any degree desired. The vacuum-pan employed is a close vessal of copper, egg-shaped, about six feet high aud four and one-half feet in diameter. It is heated by steam coils within and a steam jacket without—nclosing the lower portion. In one side of the dome is a small window through which gas illuminates the interior, while on the opposite side is an eye-glass through which the condition of the contents may be observed. The pan is also provided with a vacuum guageand test sticks. Much of the milk used in the cities is simply concentrated without any addition of sugar. The process of concentration is continued in the vacuumpan until one gallon of the milk has been reduced to a little less than a quart—one volume of condensed milk corresponding to about four and threetenths volumes of the milk. Condensed milk intended to be preserved for any length of time has an addition of pure cane sugar made to it during the boiling, and h usually put up in sealed cans. This sugared or “preserved” milk, when properly prepared, will keep for many years.