The coffee ration was what kept the army going. The government bought good coffee and issued it in whole bean to prevent unscrupulous dealers from adulterating it, and the men ground it for themselves by pounding the beans on a rock with a stone or musket butt. The veteran learned to carry a little canvas bag in which he mixed his ground coffee and his sugar ration, spooning them out together when he made his coffee. The ration was ample to make three or four pints of strong coffee daily, and on the march any halt of more than five minutes was sure to see men making little fires and boiling coffee. Stragglers would often fall out, build a fire, boil coffee, drink it, and then plod on to overtake their regiments at nightfall. Cavalry and artillery referred to infantry, somewhat contemptuously, as "the coffee boilers."
- From Mr. Lincoln's Army by Bruce Catton