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himself in difficulty during the battle of Gammelsdorf in 1313, uttered the words “Hol‘ Er d‘ Auer“ as a plea for help. This, in turn, is claimed to have resulted in the name Hallertau for the region around Au. HOP GROWING IN THE HALLERTAU There is evidence of hop growing in the region as early as the 8th century. Both Geisenfeld and Gründl bei Nandlstadt claim to have been the first place to grow hops. In 736 AD Slavonic prisoners of war fromWende are believed to have planted the first Hallertauer hops inGeisenfelden. Until the beginning of the 19th century the main growing area was in and around Spalt, near Nuremberg. It was only after the peasants’ liberation in 1848 that the requirements to promote growth were met, resulting in a production increase from 1,500 zentners in 1815 up to over 75,000 zentners in 1865. The Hallertau has been the largest integrated hop growing area in Germany since 1912. The real hop ( Humulus lupulus ) is a type of plant belonging to the hops genus, known for its use in beer brewing. It belongs to the hempseed family (Cannabacae). There are hop cultivars which have been specifically bred to be grown agriculturally. The flowers of the hop plant are referred to in the hops industry as cones (or in the German vernacular, “Hopfadroin“) and are used primarily in beer brewing. Hops have a single annual growth cycle starting around the end of March in the Hallertau on trellises in so- called hop gardens or yards. The plant is propagated using cuttings, otherwise known as rhizomes. Two or three shoots are wound around a wire which helps the plants to climb to the top of the trellis, usually about seven metres in height.When the cones are ripe, just over threeweeks (mid-August tomid- September) are spent cutting the bines just above ground level, tearing them down from the trellis and transporting them to the farmyard. The valuable hop cones are separated from the bines by a hop picking machine and then dried in a kiln down to a moisture content of 9 - 10 %. Until well into the 20th century only dried leaf hops were used to brew beer. The first records of hops being treated in hop processing facilities refer to the removal of leaves and stems followed by a drying process which included treatment with sulphur. The hops were subsequently packed in ballots of predetermined weight using hop presses at approximately 250 kg/ m3. This was a good way to optimise homogeneity. Nowadays hops are processed into a multitude of different products in technically advanced manufacturing facilities. There is a clear differentiation between “conventional hop products“, “isomerised hop products“, “aroma products“ and “other hop products“. CONVENTIONAL HOP PRODUCTS In addition to packed leaf hops there are normal pellets and enriched pellets as well as CO 2 -extract and ethanol-extract. No chemicals or substance separation methods are used to manufacture any of these products. The natural spectrum of the hop ingredients remains unchanged. These products were designed with the same brewing goals in mind as leaf hops, that is to impart bitterness and aroma in beer as well as improving its body. ISOMERISED HOP PRODUCTS The alpha acid is isomerised in a separate stage of production. Both hop powder and hop extracts can be isomerised. Some of these isomerised products are added to boiling wort while others can only be used in the cold sector, either after fermentation or directly prior to final filtration. Isomerised products are used because their alpha acid utilisation is considerably higher than that of conventional hop products. Reduced iso-alpha acid has the further special effect of improving the light stability of beer and partly improving beer foam. AROMA PRODUCTS The processing of aroma products involves a special method of separating the hop oil from the bitter substances and dosing it individually, either into the wort or in the cold sector. Hop oil can be further fractionated to produce individual aromas, most of which are detectable in the final beer. Another way of imparting hop aroma into beer is by using conventional hop products in the cold sector. This includes the use of leaf hops. This process is commonly referred to as dry hopping. A typical example of a conventional product and an aroma product being combined into a single product would be an oil-rich, fractionated CO 2 -Extract which is typically added to the wort. OTHER HOP PRODUCTS These are referred to as co-products made up with hop oil and soft resins, including the beta acids arising from the production of isomerised extracts. These can be used as a base for other hop products, i.e. aroma products or beta acid enriched extracts suited as inhibitors of microbial growth. In addition to this, newer forms of enriched hop products, created to reduce head retention during fermentation, such as xanthohumol concentrates and also some other products, are being further developed for the pharmaceutical industry. AROMA VARIETIES AND BITTER VARIETIES Aroma hops are generally very high quality varieties. As the name suggests, they have a far wider reaching aroma spectrum than the so-called bitter varieties more commonly used in the brewing process. Aroma varieties develop an unusual intensity during brewing, giving the beer wonderful character and body. The resulting beers offer a broad spectrum of impressions, ranging from “citrussy“ to “fruity“ and “floral“ and even “herbal“ and “caramel- like“. It should be noted that although the level of bitter substances in most aroma varieties is quite low, they nevertheless play a significant role in the brewing process. In order to impart the required bitterness into beer, you need considerably higher volumes of ADVERTORIAL 70 | Winter 2019 | ontapmag.co.za