A Curative Method for Primary Gushing of Beer and Carbonated Beverages: Characterization and Application of Antifoam Based on Hop Oils

Abstract

J. Am. Soc. Brew. Chem. 72(1): [12][13][14][15][16][17][18][19][20][21] 2014 Gushing is the vigorous overfoaming of carbonated beverages when the bottle is opened. Primary gushing in beer is mostly caused by a group of proteins called hydrophobins secreted by filamentous fungi, which contaminate CO 2 gaseous molecules during carbonation and form nanobubbles. The influence of hop oil antifoam on primary gushing showed a complete suppressing effect in sparkling water, a decreasing effect in wort, and no influence on gushing-positive beers. This shows the importance of the critical point of addition of this product in the brewing process. GC and GC-MS analysis show that commercial available lipophilic hop extract comprises fatty acids, either saturated fatty acids (SFA) or unsaturated fatty acids (UFA) (both free and incorporated in mono-, di-, and triglycerides), waxes (long-chain alkanes), and steroid compounds. Gushing analysis of each compound showed that SFA and UFA behave in a different manner regarding gushing. In contrast to SFA and trans-form UFA, cis-form UFAs do not induce gushing. Long-chain alkanes provide sufficient hydrophobic structures to interact with gaseous CO 2 molecules and induce gushing. Because hop antifoam molecules are hydrophobic, they interact with hydrophobins and prevent interaction with CO 2 and, consequently, inhibit the possibilities of development of the explosive nanobubble structure.

The Gushing Experience—A Quick Overview

“…Hop extracts are commonly used in brewing in order to control the foam in boiling kettles and fermenters. Adding such an extract before carbonation is effective for gushing reduction [68]. The extract addition has a better effect when added to wort after cooling, and before fermentation.…”

Effect of a magnetic field on dispersion of a hop extract and the influence on gushing of beer

“…The major components of the hop extract are waxes (C29 and C31) which are strong gushing inducers (Shokribousjein et al, 2014) while some unsaturated fatty acids were gushing inhibitors. Based on the total amount of individual molecules in the hop extract, it is found that the majority of the molecules are gushing inducers.…”

“…Such extract is a suitable alternative in order to decrease gushing and the result showed that it decreases gushing of beer when it is added before carbonation (Shokribousjein et al, 2014). The extract creates an interface in wort with which hydrophobins interact and further contact with gaseous CO 2 is inhibited.…”

“…These nanobubbles are very stable and addition of the hop extract did not destabilize them as much. Therefore, addition of the hop extract to the finished beer is not a useful method to decrease gushing (Shokribousjein et al, 2014) and the extract should be used before carbonation to inhibit gushing. In a research it was shown that destabilization of the formed nanobubbles are possible through dropping of the crates of gushing beers (data not published yet) or pasteurisation (Garbe et al, 2009).…”

Co‐encapsulation of lupulon and xanthohumol in lecithin‐based nanoliposomes developed by sonication method

“…Hop extracts usually used in breweries for possessing the specific tastes and aroma (Shokribousjein et al, ; ). The acidic constituents of the hop plant ( Humulus lupulus ) not only elicit bitter taste but also have antimicrobial activity against a wide spectrum of food spoilage bacteria such as Lactobacillus spp.…”