The vacuum tank will hold, perhaps, nine thousand quarts. It has a glass window at the top, through which the operator in charge looks from time to time. He can tell by the appearance of the milk when the time has arrived to shut off the steam, and this must be done at just the right moment, else the batch will be spoiled.
Next the condensed milk is drawn into forty-quart cans, which are set in very cold spring water, where they are made to revolve rapidly by a mechanical contrivance in order that their contents may cool evenly.
When the water does not happen to be cold enough, ice is put in to bring it down to the proper temperature. Finally the tin cans of market size are filled with the milk by a machine, which pours into each one exactly sixteen ounces automatically, one girl shoving the cans beneath the spout, while another removes them as fast as they are filled.
People in cities nowadays use condensed milk largely in preference to the uncondensed, regarding it as more desirable because of the careful supervision maintained by the companies over the dairies from which they get their supplies.
For their consumption the product is delivered unsweetened, but even in this condition it will last fresh two or three times as long as the ordinary milk by reason of the boiling to which it has been subjected. Milk fresh from the cow contains eighty-eight per cent.
of water, condensed milk twenty-eight per cent.
After condensed milks come condensed jellies. They are made in the shape of little bricks, each weighing eight ounces, and with an inside wrapper of oiled paper. According to the directions, the brick is to be put in one pint of boiling water, and stirred until it is dissolved.
The mixture is then poured into a mold or other vessel and put into a cool place. In a few hours the jelly is “set” and ready to use, a pint and a half of it. It never fails to “jell,” which point is the cause of so much anxiety to amateur jelly-makers.
We have often heard that “one egg contains as much nourishment as one pound of meat,” which shows that nature has condensed the food essentials in this instance. But man has condensed them still more, mainly, however, because eggs have a bad habit of getting stale.
Great quantities of eggs are bought up in summer when the price of them goes down to almost nothing. They are broken into pans, the whites and yolks separated and evaporated to perfect dryness. Finally, they are scraped from the pans and granulated by grinding, when they are ready for shipment in bulk.