R. Juerst – Pure Products American Brewer’s Review Vol. XXXI No. 5 May, 1917
The author advocates the use of ground hops instead of whole hops for dry hopping. At the present time it is customary in America to add the raw hops to the storage vat or the chip cask at the time of ﬁlling, or to introduce them through the bung-hole after the vats have been ﬁlled. In the ﬁrst case the hops are introduced in the loose state or enclosed in bags; and in the second case the hops, added through the bung-hole, ﬂoat for a considerable time on the surface of the ale and gradually sink to the bottom.
The quantity of hops added may vary from ¼ lb. to 4 lbs. per barrel. In the production of stock ales and cloudy ales, the latter of which have become very popular in certain parts of New England States, a certain quantity of hops is added to the ale in the barrel itself, and the ale is then either primed or allowed to undergo a secondary fermentation, or it is sent out in barrels containing the hops without being primed. In the case of dry hopping at the storage vat or chip cask, either whole hops or hops in a separated state (sometimes mixed with whole hops) are used.
Some brewers prefer to use in part some of the lupulin which has been separated from the hops by means of the well known hop-separating machine, mixing the lupulin with whole or separated hops. The aim is always to derive the greatest benefit from the smallest possible quantity of hops. In dry hopping the ﬂavoring matters cannot be extracted so completely as in wort-boiling, and the ale to be hopped must therefore be stored for a considerable time with hops; but even then the latter are not fully utilized, and are afterwards usually in a ﬁt condition to be used for some other purpose it if were not for the yeast and other matters with which they become contaminated.
In some English breweries it has been attempted to wash the hops after use, and employ them in the copper, but this practice has not become general. If used in the copper in considerable amounts, without first being washed, they would be liable to impair the flavor of the ale produced. The author has obtained satisfactory results by employing ground hops for dry-hopping and even in the copper.
The mill employed, driven by a 6 horse power electric motor, and making 400 revolutions per minute, was capable of grinding 200 lbs. of hops per hour, whether in a moist condition or dry. The lupulin glands were thereby laid open and their contents spread over the disintegrated leaves of the hop-cones. The mill could be adjusted for coarse or ﬁne grinding. Spindles, stems and leaves were all passed through the mill. While the spindles and stems act favorably upon the ale to be dry-hopped, it has been demonstrated, contrary to a belief widely entertained, that the seeds have no bitter ﬂavor of the ale treated. It was found that by grinding hops in this way the quantity required can be reduced by more than 50 per cent.
Ground hops added to ale in the storage vessel form a more compact deposit at the bottom than whole hops, and retain less than one third of the amount of beer absorbed by the latter. After use they can be flushed from the storage vessel directly into the sewer. The amount of time and labor saved by this method of hopping is considerable. As regards the use of ground hops in the copper, satisfactory results have been obtained on a large scale, but further data are promised in a later paper.