Today in 1951, US Patent 2559107 A was issued, an invention of Verlin A. Bloxham, for his “Drying Hops.” There’s no Abstract, although in the description it includes this summary:

This invention relates to an improved process for the drying of hops.

The common process employed, in lowering the moisture content of hops from 75% to 80% to 7 to 11%, involves the use of apparatus including a house-like structure having a reticulated floor upon which the hops are loaded. Beneath the floor there is disposed a heater, commonly direct fired, and the products of combustion from which usually pass through a zigzag or like arrangement of large pipes, located beneath the hop floor, on the way to the stack. Forced draft of air through the hops is not provided, the house being tall compared to its section so as to provide a stack effect, the hop-floor being some twenty feet above ground level. There are a great number of objections to this manner of drying, the major one probably .being the variable quality of the dried product. This variable quality is clue to several factors inherent in the process employed, one of the main ones of which is that the drying is more efficient in the lower portion of the bed, with the result that if the bed is not turned one or more times during the drying process, the drying will not -be uni,- form and hops in one portion of the bed will be of a different moisture content from those in another portion.

The turning of the hops, to ensure uniformity in drying, has its own drawbacks. After the hops dry, they become very fragile and brittle and easily broken, and when the bed is turned to reverse the position of the upper and lower layers, many of the cones which have reached the brittle state will be broken, and the product taken from the dryer will have an excessively high proportion of fines. The labor involved in this operation is, of course, objectionable in addition.

As will be apparent from the above description of the apparatus, the hops are subjected not only to heat by convection from the pipes, but also to radiant heat. For this reason, though ordinary dry bulb thermometers are customarily used in order to control the temperature Within the bed, the lower layers of hops to which heat is radiated will be at temperatures higher than that indicated by the thermometer. This consideration, of course, renders the control by thermometer inadequate and misleading and constitutes one of the reasons for lack of uniformity in the product, since the hop is extremely sensitive to excessive temperature. Further, action of this radiant heat is to raise the temperature to excessive levels of those portions of the enclosure which are seen by the pipes. This results in the successive drying, charring and perhaps final combustion of the combustible material, generally wood, employed in construction of the driers; the loss of the driers by fire is a common occurrence.

A still further serious objection is encountered due to the fact that fines fall from hops through the floor and onto the hot pipes where they become charred and give rise to vapors which in turn pass through the hops and may be condensed on or absorbed by them.

The driers are tall, as referred to above, which increases the difficulty and labor involved in loading, turning and unloading. Floor loading is limited to a depth of about twenty-four inches. The heating system is inefficient, wasting as much as 50% of the heat.

The present invention contemplates the continuous drying of hops, thus avoiding any delay between the harvesting of the hops and the drying operation. This facilitates the harvesting operation inasmuch as it is not necessary to assemble a kiln charge prior to the drying operation for loading into the kiln. Thus, the drying operation and the harvesting operation can be coordinated and carried on simultaneously and continuously.