John Billings was a veteran of the 10th Massachusetts Volunteer Artillery Battery who wrote a popular book in 1887 called “Hard Tack and Coffee: The Unwritten Story of Army Life” in which he detailed every aspect of day to day life in the Union army. Here is his description of daily rations.
Here is just what a single ration comprised, that is, what a soldier was entitled to have in one day. He should have had twelve ounces of pork or bacon, or one pound four ounces of salt or fresh beef; one pound six ounces of soft bread or flour, or one pound of hard bread, or one pound four ounces of corn meal. With every hundred such rations there should have been distributed one peck of beans or pease; ten pounds of rice or hominy; ten pounds of green coffee, or eight pounds of roasted and ground, or one pound eight ounces of tea; fifteen pounds of sugar; one pound four ounces of candles; four pounds of soap; two quarts of salt; four quarts of vinegar; four ounces of pepper; a half bushel of potatoes when practicable, and one quart of molasses.
Desiccated potatoes or desiccated compressed vegetables might be substituted, for the beans, peas, rice, hominy, or fresh potatoes. Vegetables, the dried fruits, pickles, and pickled cabbage were occasionally issued to prevent scurvy, but in small quantities. But the ration thus indicated was a camp ration.
Here is the marching ration: one pound of hard bread; three-fourths of a pound of salt pork, or one and one-fourth pounds of fresh meat; sugar, coffee, and salt. The beans, rice, soap, candles, etc., were not issued to the soldier when on the march, as he could not carry them.