Today in 1882, US Patent 2356545 A was issued, an invention of Marshall J. Allen, for his “Process of Making Whisky (from Spent Beer).” There’s no Abstract, although in the description it includes this summary:

The object of our invention is to increase the yield of whisky from a given amount of grain by utilizing in subsequent processes the refuse products of previous processes, and this we do by first preparing the refuse product and bringing it into a condition in which it may be advantageously used; and, secondly, by introducing such prepared product into the subsequent processes of whisky-making.

In all those methods of making whisky in which the entire grain introduced passes through the entire process and is delivered as a refuse product at the end of the operation The sheet of drawings hereto annexed rep resents a general View of a part of a distillery arranged for the practice of our improved process. We do not limit ourselves, however, to the special apparatus for carrying out the process, but show one form of apparatus by which it may be carried into effect. We shall not go into detail in the description of this apparatus, as the arrangement will be easily understood by those acquainted with the art.

By “preparing the refuse product,” he means what they call “spent beer,” which I further assume he means “spent grain,” though to be fair I’m not quite sure. A little later in the description, they explain it somewhat better:

In the drawing, A represents the mash-tubs B, the mill-hoppers; C, the millstones; D, the beer-still; E, low-wines receiver; F, doubler still; G, beer heater and charger; H, low-wines charger for doubling still; I, doubling still, condenser, and flake-stand; J, beer-still; K, fermenting-vats; L, whisky-receiver; M, hot-slop or spent-beer receiver; N, hot-slop connection with our improved process.

It is well known that the spent beer contains in suspension, in the first place, a considerable amount of refuse material of comparative large size such as the chaff, bran, and larger particles of grain and, in the second place, minute particles of sugar or glucose, starch, and yeast. This second class of parti- 7o cles it is very important to preserve and introduceinto the subsequent operations of whisky-making. This second class of particles are so minute as that they will pass through the meshes of a fine sieve, and yet are sufticiently solid and separate from the liquid to form a deposit in any vessel in which the liquid may remain at rest. The purpose of our invention is to retain these fine or valuable particles in the liquid which is to be returned, and to separate from this liquid the coarse or refuse particles, while at the same time the liquid is maintained in a sweet condition.