PRODUCTION AND CONSERVATION OF FATS AND OILS. 35 
during the five-year period 1913-1917, 12,000,000 cattle having been 
killed in 1913 and 15,600,000 in 1917, a very rapid increase. It is 
stated also that the slaughter of calves increased proportionately. 
Our exports of tallow, as such, have decreased from an annual pre- 
war average of 28,600,000 pounds to a little more than 7,500,000 in 
1917, and the exportation of oleo oil shows a corresponding decrease. 
It is interesting to compare the exports of straight tallows with those 
of tallow derivatives (Table 5). Such a comparison brings out the 
fact that foreign countries do not demand as much hard tallow and 
the harder oleostearin as they do the semisolid portion of the tallow — 
the oleo oil. This country produces practically one-fourth as much 
tallow as lard, and the 259,509,000 pounds of tallow constitute a 
little less than 16 per cent of our total animal and fish fat and oil 
output. Considering the tallow production, oleo stock must also be 
taken into account, as this is really only a high grade of edible tallow 
derived from cattle and is used primarily for the manufacture of oleo 
oil and stearin. If we include the 153,188,000 pounds of this fat 
reported in 1917 with the tallow, we have a total of 412,697,000 
pounds. This places the tallows third in the domestic production of 
all fats and oils. 
PREPARATION OP TALLOW AND TALLOW DERIVATIVES. 
The modern packing-house method of handling beef fat is similar 
to that used in the preparation of hog fats. A larger portion of lard 
than of tallow, however, is made in open kettles. In the smaller 
packing houses, which are not under Federal inspection, practically 
the entire output of tallow is either sold as such, or mixed with cotton- 
seed or some other vegetable oil to form a compound. On the other 
hand, the big packers convert a great deal of their edible beef fat 
into oleo oil and stearin. These are separated by a process known as 
" graining," which is similar to "wintering" as applied to vegetable 
oils, to separate the stearin and produce oils that will not become 
cloudy in cold weather. The graining process consists in running 
the meltea oleo stock into large truck tanks, which are then wheeled 
into the graining room, where the stock is allowed to stand undis- 
turbed at the crystallizing temperature of the stearin for a day or 
longer. When the stearin has separated from the oil, the batch is 
sent to the press room, also kept at a constant temperature, and the 
semisolid mass of stock is pressed in hydraulic or lever presses. As 
it runs from the presses the oleo oil is pumped into storage tanks, and 
later barreled either for the export trade or for use in domestic mar- 
garine manufacture. The solid cakes of stearin are stripped from 
the press cloths, melted, and stored in barrels for use in making lard 
substitutes. 
