Gushing
Gushing ( English to gush = to pour out) is the seldom, sudden and spontaneous foaming of a carbonated drink from a bottle or can without shaking it first. Gushing can affect all carbonated, ie carbonated, drinks such as beer, sparkling wine, sparkling wines and champagne, as well as fruit juice spritzers and mineral water.
This is a chemical - physical phenomenon, the exact causes of which have not yet been fully clarified despite many years of research. The carbon dioxide content is the driving force behind gushing, but it is not the cause. So-called condensation nuclei , the smallest particles or microbubbles, are required so that the carbon dioxide can spontaneously release .
With regard to the causes, a distinction is made between two forms of gushing, which are called primary and secondary gushing. Raw material influences (brewing grain for beer, grapes and fruit for sparkling wine and juice spritzers) are assumed to be the cause of primary gushing, while various technological causes such as particles and crystals in the drink or roughness on the inside of the bottles or cans, which act as condensation nuclei, are assumed to be the cause of secondary gushing serve, could be found. The technological causes are largely known and can be controlled and avoided with appropriate technological guidance.
The causes of primary gushing, on the other hand, have not yet been conclusively clarified and numerous national and international research teams are investigating the causes. Currently, the likely cause is the weather-related fluctuations in the quality of natural raw materials.
Gushing test
To characterize raw materials such as B. malt or raw fruit, and the Modified Carlsberg Test is used to predict possible gushing in the end product . For this purpose, a cold water extract of a malt or raw fruit coarse meal is mixed with standardized table water after it has been concentrated by boiling. After shaking and opening the bottles in a defined manner, the weight of the amount of liquid overflowing is determined and viewed as a measure of the gushing potential of the malt or the raw fruit.
beer
In the case of beer , a natural product , vintage-related fluctuations in quality as a result of different weather conditions in the growth phase of the brewing grains barley and wheat are suspected to be the trigger for the very rare primary gushing. Especially in wet years can occur in the grain to significant changes after view of modern science to increased gushing potential of the produced therefrom malts lead. Damp weather during so-called tillering, flowering or harvesting promotes the formation of the above-mentioned condensation particles. In this context, field contamination with microorganisms and defense reactions of the plants are also discussed.
Even the slightest contamination, which is far from being a health hazard for consumers, is enough to trigger gushing.
So far it has not been possible to clearly identify these naturally present gushing-causing substances analytically and thus to remove them during the malt and beer production. To make matters worse, gushing is not a monocausal phenomenon, but rather arises from the interaction of raw materials, brewing water composition and the nature of the bottles. Beer in which gushing has occurred does not differ analytically or in terms of taste from "normal" beer and is not harmful to health.
Usually gushing does not appear until several weeks after the beer is bottled. Gushing is a very rare vintage-related raw material phenomenon that can occur in the natural product beer and on which malthouses and breweries have little influence in the context of beer production.
Sparkling wine
In the case of sparkling wine , gushing can be caused by an imperfect surface of the glass bottle or by crystals in the liquid.
Individual evidence
- ↑ Ludwig Narcissus: Demolition of the brewery. 6th revised edition. Ferdinand Enke Verlag, Stuttgart 1995, ISBN 3-432-84136-1 , p. 327.
- ↑ HP Bach, S. Görtges, K. Burger, R. Schneider: The wild or gushing of sparkling wine. In: German viticulture. 2001, pp. 36-41.
- ↑ a b Thomas Schumacher: Gushing in fruit juice spritzers. Part 1 - Causes of the strong foam formation. (PDF file; 132 kB). In: Beverage Industry. 7/2002, pp. 8-10; Part 2 - Measures to avoid foam formation. In: Beverage Industry. 8/2002, pp. 25-27.
- ^ Sven Fischer: Bubble formation of gases dissolved in liquids. ( Memento of October 15, 2013 in the Internet Archive ) (PDF file; 2.1 MB), dissertation . Technical University of Munich 2001.
- ↑ M. Zepf: Gushing cause finding on the basis of model experiments. Dissertation. Technical University of Munich, 1998.
- ↑ RADAU, A .; LINEMANN, Annet; KRÜGER, E .: Modified Carlsberg Test (MCT). In: Brewery Forum 23 (1995), pp. 377-378.
- ↑ Susanne Hippeli, Erich F. Elstner: Are Hydrophobins and / or Non-Specific Lipid Transfer Proteins Responsible for Gushing in Beer? New Hypotheses on the Chemical Nature of Gushing Inducing Factors. In: Journal of Nature Research C . 57, 2002, pp. 1–9 ( PDF , free full text).
- ↑ Sebastian Loitsch: Influence of surface tension on the foaming of beverages.