The Suppression of Gushing by the Use of Hop Oil

J. Inst. Brew. 116(4), 339-347, 2010Malt-induced gushing is a problem that has been known for many years. Mechanisms and inducing agents are still not fully understood and identified. Hydrophobins produced by various filamentous fungi are currently under discussion as biological gushing-inducing compounds. In the current study the class II hydrophobin FcHyd5p, from the cereal pathogen Fusarium culmorum, was employed in beer and other carbonated beverages for gushing experiments and the influence of hop compounds on gushing potential was examined. It was demonstrated that this protein strongly induces gushing in various carbonated beverages, including beer. It was further demonstrated that the resulting gushing volume is susceptible to certain hop compounds and can be decreased significantly by the addition of these substances.

Section: Discussionsupporting

confidence: 94%

Induction of Gushing with Recombinant Class II Hydrophobin FcHyd5p fromFusarium culmorumand the Impact of Hop Compounds on its Gushing Potential

Lutterschmid

Stübner

Vogel

et al. 2010

“…A summarized extract of the scientific articles by Hanke et al [37][38][39] is presented in the following section. The gushing reducing effect of hop components such as linalool, hop oil and humulones, already known from former research 8,25,26,62,73,78 , was confirmed by their latest experiments 38,39 . The results supported observations in the brewing industry that beer with a higher hop addition (e.g., pilsner beer) shows lower gushing propensity than beer with a lower amount of hop addition.…”

Section: Introductionmentioning

confidence: 67%

Novel Perspectives in Gushing Analysis: A Review

Manuel

Titze

Ilberg

et al. 2011

The phenomenon of gushing, characterized by the spontaneous overfoaming of carbonated beverages directly after opening a bottle (or a can), can still be a problem for the brewing and beverage industry worldwide. Due to its sudden and partly eruptive character, gushing can be detrimental to the image of the industry when it occurs in the hands of the consumer. Gushing is a complex phenomenon, induced by a variety of gushing factors of the raw materials and in the production process. A reliable methodology to avoid gushing is not yet available. Nevertheless, the obvious measure to prevent or at least minimize gushing is to assess the raw materials for their risk of gushing before they are processed further in production. Thus, the investigation of gushing analysis plays a particular role in the industry to prevent gushing and also in research to get more cognition on this phenomenon. This article gives a review of gushing with the focus on analysis. In current gushing tests, the overfoaming amount of bottled and carbonated extracts of the examined raw materials is used to determine the extent of the gushing potential. However, these analytical methods have disadvantages. The overfoaming amount can fluctuate, making it difficult to quantify the gushing potential precisely and the performance of these tests takes time (some days), which can lead to the unfavourable situation where the raw materials have already been processed before gushing could be detected. Therefore, the thematic priority of this review article is to present new ideas to quantify gushing more precisely and novel analytical approaches for the prediction of gushing by applying combined particle analysis.

“…Diverse experiments have shown that the volatile hop compounds (i.e., the hop oils), in particular ones that are not evaporated in such a set-up, can diminish the amount of gushing. More detailed information about the anti-gushing effects of hop oils can be found in the literature 1,6,10,11,15,20,21 . Many researchers have focussed on the relationship between fatty acids and the overfoaming volume 1,2,9,11,14,18,24 .…”

Section: The Influence Of the Hop Variety On The Overfoaming Volumementioning

confidence: 99%

“…Hops in particular contribute to a wide range of both aspects, depending on the sole point of usage or type of product. Inhibitory effects are shown by α-acids 13,14,20,21 and the unsaturated fatty acids that are included in hop oils 2,11,14 . A late hop addition that favours the transfer of linalool into the wort can also suppress the gushing volume 14 .…”

Section: Introductionmentioning

confidence: 99%

Impact of Different Hop Compounds on the Overfoaming Volume of Beer Caused by Primary Gushing

Müller

Schmid

Becker

et al. 2010

When weather conditions favour the growth of moulds on barley, beers brewed from the resulting malts often tend to gush. Certain Fusarium species (e.g., F. graminearum and F. culmorum) may cause this problem. Supersaturated with CO 2 , a primary gushing beer contains an overcritical concentration of microbubbles; these are reputed to be stabilised by Fusariumderived hydrophobins. Research with varying brewhouse parameters has been performed to investigate the factors of primary gushing. As hops are known to contribute to a wide range of both gushing positive and negative substances in beer, the hopping regime has emerged as an important aspect. This paper examines the impact of different hop varieties on gushing. Hop oils and unsaturated fatty acids are reputed to be gushing-suppressors. Compounds such as dehydrated humulinic acid can intensify the effect. Hop pellets, with a prevalent range of conductometric values (5-10% α-acid), commonly employed in breweries to adjust bitterness and aroma were selected. By working with the same "gushing malt", the spectrum of compounds in the finished beer only differed through the hop product used. The overfoaming volumes of different samples were determined according to MEBAK guidelines. Respective hop oil and fatty acid concentrations (by GC) and iso-α-acid contents (by HPLC) were compared and a chronological sequence of the changing percentages of beer loss is shown.