Wild hops

Pillay, M. and Kenny, S. T. 1996. Structure and inheritance of ribosomal DNA variants in cultivated and wild hop Humulus lupulus L. Theor. Appl. Gen. 93 333-340. 

Minnesota, Iowa, and Illinois (9). As indicated by its common name, the hop-vine borer had been found in close association with hop (Humulus lupulus) plants. Wild hops, found from the east coast of the U.S. to the Rocky Mountains, presumably served as the primary host for the Insect in North America (10) for the last 100-150 years or longer. 

White bryony, wild hops, English mandrake, wild vine, ladies seal)... 

Breed, W. G., 1976, Effect of environment on ovarian activity of wild hopping mice (Notomys alexis), J. Reprbd. Fert., 47 395. 

Beer taste can be spoiled by contaminating bacteria or yeasts. The most common bacteria are lactic and acetic acid producers and T ymomonas. Wild yeasts can be anything other than the intended strain S. uvarum is considered a contaminant of ale fermentations and S. cerevisiae a contaminant of lager fermentations. The common wild yeast contaminants are S. diastaticus and species of Picbia, Candida and Brettanomjces. It may be noted that the flavor of beer may be improved by the ability of yeast to adsorb bitter substances extracted from hops, such as humulones and isohumulones. 

Hops. Hops are the blossoms of the female hop plant, wild in North and Middle Europe, North Asia, and North America. The composition of hops is shown Hi Table 5 (see also ref. 11). 

Clark, D.C., Wilde, P.J., and Wilson, D.R. The effect of pre-isomerized hop extract on the properties of model protein stabilized foams, /. Inst. Brew., 97, 169, 1991. 

A kind of yeast used extensively before the innovation of pure culture yeast cakes was known as potato yeast or wet yeast. This was made by developing the wild yeast on potatoes or hops. Either potatoes or hops were made into a decoction with water and were allowed to stand in a warm place until the wild yeast had had time to multiply in sufficient numbers. This decoction was added to the dough in bread making. 

Intraperitoneal administration of alcoholic extracts of the Magnum variety of hops at doses of 10 ml/kg (1 2 extract) to mice, one day to several hours prior to receiving 25 mg/ kg cocaine, almost completely suppressed the action of cocaine compared to controls. Other varieties (Aroma and wild genotypes) administered according to the same regimen also decreased the cocaine-induced locomotor activity of mice, but to a lesser extent (Horvat et al. 2007). 

Ethanol extracts of Magnum and Aroma varieties of hops, intraperitoneally administered to mice at doses of 10 ml/kg four times in 24 hours prior to administration of pentobarbital (40 mg/kg) or diazepam (3 mg/kg), suppressed the hypnotic action of the drugs. No effects on pentobarbital and diazepam were observed after administration of the same extract of a wild genotype of hops (Raskovic... 

The nonspoilage variants were obtained by repeatedly subculturing the wild-type strains at 37 °C for L brevis, 30 for Lactobacillus paracollinoides, 30 for Lactobacillus lindneri, and 35 °C for Pediococcus damnosus, respectively. The superscripts NB and CC indicate the hop-sensitive variants obtained from beer-spoilage wild-type strains with the same strain number. 

The antibacterial properties of hops are one of the main reasons for their use in brewing. Hops are dried down to 8-10% moisture to prevent spoilage but nonetheless remain susceptible and, as with other raw materials, checks should be made for each batch as a matter of quality control. A number of breweries carry out dry hopping post-brew-house which increases the risk of introducing contaminants. For hops the most likely microbes are fungi, molds, and mildew and the tolerance is less than lOcfu/g, with zero tolerance of wild yeast. 

Myrcene is a very abundant acyclic monoterpene available from the essential oils of various plants including wild thyme and hops. Recently, an excellent overview on the manufacture and transformation of this natural product was given by Behr and Johnen [125]. Commercially, myrcene is produced by the pyrolysis of pinenes [126]. The rhodium-catalyzed hydroformylation of myrcene gives usually a mixture of fragrance aldehydes in more than 90% combined yields (Scheme 6.37) [127, 128]. The main aldehyde, which accounted for 70 - 80% of the mass balance, results from the reaction with the less substituted C=C bond through the formation of a T) -allyl rhodium intermediate complex [127]. The reaction was also performed in a toluene/water biphasic system using the water-soluble TPPTS ligand and a cationic surfactant [84]. 

Humulenes (167) and (168), which were detected in various oils, presumably do not play an essential role in hop oil [odor threshold in water solution 120 ppb (71)]. Oxygen-containing humulene derivatives, among which epoxides (169) and (170) (77), humulol (174) (428) and ketones (176) and (177) (429) were identified, might contribute much to the hop character imparted to hop beverages (71). All these substances (167) to (173) as well as zerumbone (175) were first isolated from the essential oil of wild ginger (99, 100, 101). 

Hops are grown for commercial purposes in most of the moderate climate zones of the world. Hop growing areas are situated between latitudes 43 -54° (Europe), 38°-5l° (North America), 38 -51° (Japan) in the Northern hemisphere and between 37°-43° (Australia), 41°-42° (New Zealand), 35°-40 (Argentina) in the Southern hemisphere. Wild growing hops are also found in these parts of the world. 

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