Uptake and Release of Ca, Cu, Fe, Mg, and Zn during Beer Production

Wietstock, Philip C.; Kunz, Thomas; Waterkamp, H.; Methner, Frank‐Jürgen

doi:10.1094/asbcj-2015-0402-01

Cited by 30 publications

(34 citation statements)

References 26 publications

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“…Numerous patents exist for technologies aimed at reducing the transition metal content of beer, but this can be challenging as metal content is dependent on multiple factors such as the metals concentrations naturally found in the ingredients used and the potential for metal leaching from brewery equipment [5][6][7][8]. Transition metals are often present in beer at levels sufficient to catalyze these oxidative reactions (>50 µg/L), resulting in a more rapid loss of product quality over time [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

“…Metal concentrations in brewing ingredients like hops and malt are dependent on growing conditions and processing and are generally outside the brewer's control. The largest reservoir of potential transition metals in the brewing is the malted barley or other cereal grains, as they are used in much larger quantities relative to hops on a weight basis [8]. A study by Wietstock and Kunz found that despite the fact that grains contain relatively high concentrations of transition metals (4 mg/kg Cu, 34 mg/kg Fe, 18 mg/kg Zn, and 1133 mg/kg Mg), they are tightly bound to the grain, and the majority (61.8% Cu, 95.2% Fe, 86.2% Zn, and 77.6% Mg) remain in the spent grains which are separated from wort during lautering [8].…”

Section: Introductionmentioning

confidence: 99%

“…The largest reservoir of potential transition metals in the brewing is the malted barley or other cereal grains, as they are used in much larger quantities relative to hops on a weight basis [8]. A study by Wietstock and Kunz found that despite the fact that grains contain relatively high concentrations of transition metals (4 mg/kg Cu, 34 mg/kg Fe, 18 mg/kg Zn, and 1133 mg/kg Mg), they are tightly bound to the grain, and the majority (61.8% Cu, 95.2% Fe, 86.2% Zn, and 77.6% Mg) remain in the spent grains which are separated from wort during lautering [8]. While hops are used in smaller quantities compared to grains on a weight basis, they contain higher concentrations of transition metals, which have been demonstrated to contribute significantly to the final metal load of finished beer [5,8].…”

Section: Introductionmentioning

confidence: 99%

“…A study by Wietstock and Kunz found that despite the fact that grains contain relatively high concentrations of transition metals (4 mg/kg Cu, 34 mg/kg Fe, 18 mg/kg Zn, and 1133 mg/kg Mg), they are tightly bound to the grain, and the majority (61.8% Cu, 95.2% Fe, 86.2% Zn, and 77.6% Mg) remain in the spent grains which are separated from wort during lautering [8]. While hops are used in smaller quantities compared to grains on a weight basis, they contain higher concentrations of transition metals, which have been demonstrated to contribute significantly to the final metal load of finished beer [5,8]. Transition metal contributions from hops are of greater potential concern in dry-hopped beers where hops are added directly to fermented beer in quantities that generally exceed those used in kettle hopping [12].…”

Section: Introductionmentioning

confidence: 99%

“…When hops are added to the wort, metals can be complexed and removed from the wort through co-precipitation with proteins and phenolics in trub during the boil or through complexation and sequestration by yeast during fermentation, both of which are removed during the brewing process by filtration [8,13,14]. Higher concentrations of transition metals have been found in dry-hopped beer, and few remedial opportunities remain between dry hopping and final packaging, leading to a loss of stability of the finished product [11].…”

Section: Introductionmentioning

confidence: 99%

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Impact of Copper Fungicide Use in Hop Production on the Total Metal Content and Stability of Wort and Dry-Hopped Beer

2020

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Transition metals, including copper, iron, and manganese, are known to catalyze the generation of reactive oxygen species (ROS) in beer leading to reduced product stability. Metals in beer are generally derived from raw ingredients. The present study aims to evaluate the impact of brewing and dry-hopping using hops treated with copper-based fungicides (CBFs) on the final transition metal content of model buffer solutions and pilot-scale systems of wort and beer. Copper levels in model wort and beer solutions were elevated (105.6% and 230.4% increase, respectively) when CBF-treated hops were used. In laboratory-prepared wort, elevated copper concentrations were not observed when CBF-treated hops were used for boiling. Dry hopping of beer using CBF-treated hops led to significant increases in total copper content (ca. 75 µg/kg vs. ca. 40–50 µg/kg in the control-hopped beer) when yeast was absent from the treated beer, but not when yeast was present. It was observed that manganese levels were significantly elevated in all hopped beers (ca. 495–550 µg/kg vs. 90–125 µg/kg in the unhopped control), regardless of hop treatment. A hop varietal thiol, 4-Mercapto-4-methylpentan-2-one, was spiked into treated beers, and the rate of oxidative loss was monitored during aging. Rates of thiol loss in treated beer samples did not differ across CBF treatments but were significantly lower in unhopped controls in the absence of yeast (p < 0.0001) and correlated significantly with total manganese content of the beers (R2 = 0.4228, p = 0.0006). The rate of staling in hopped beers as measured by the rate of 1-hydroxyethyl radical generation did not differ among hop treatments, suggesting that excess copper content contributed from the hops does not negatively impact the oxidative stability of the beers. These findings suggest that brewers can use CBF-treated hops without any negative implications for the shelf stability of their beers and do not contraindicate the use of CBF in hops production when necessary.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Impact of Copper Fungicide Use in Hop Production on the Total Metal Content and Stability of Wort and Dry-Hopped Beer

2020

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On the contribution of malt quality and the malting process to the formation of beer staling aldehydes: a review

et al. 2021

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Despite decades of extensive research, beer flavour instability remains a challenge for both brewing and malting industries. Malt impacts the brewing process as well as the quality of the final beer. It also affects the stability of beer flavour, as it delivers to the brewing process various compounds with the potential to compromise the desired flavour characteristics of beer. These include staling aldehydes and their precursors, such as amino acids, reducing sugars, α‐dicarbonyls and bound‐state aldehydes. In general, the content of these compounds depends on barley variety and quality, the malting regime and final malt quality. Malt that represents a low potential for beer staling, i.e. that has low values of Kolbach Index, heat load, colour, LOX activity, Strecker aldehydes, transition metal ions and high antioxidative activity, leads to beer with enhanced flavour stability. However, the consistent production of malt with the desired quality remains challenging. Approaches to achieve this include adjustment of steeping and germination conditions, allowing control of grain modification and thus, the reservoir of aldehydes precursors. Also, the application of alternative kilning technologies may reduce the applied heat load, responsible for the formation of staling aldehydes and triggering development of the oxidising free radical species. This review provides an evaluation of current knowledge on the contribution of the malting process and malt quality to the formation of beer staling aldehydes. © 2021 The Authors. Journal of the Institute of Brewing published by John Wiley & Sons Ltd on behalf of The Institute of Brewing & Distilling.

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The influence of yeast strain on the oxidative stability of beer

Jenkins

James²,

Dehrmann³

et al. 2021

J. Inst. Brew.

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Flavour stability, or instability, relates to the rate of flavour change through the shelf‐life of packaged beer. There are several control points in the production of beer where flavour stability may be altered. These include fermentation and the influence of yeast is key. Greater insight into the yeast traits which contribute to flavour stability may help yeast strain selection in the future. Knowledge of the key phenotypes may also lead to improved yeast handing or monitoring practices. In this study, 11 yeast strains, previously characterised according to their sensitivity to oxidative stresses (induced by menadione and hydrogen peroxide) were screened using miniature (100 mL) fermentations and the oxidative stability of the resultant green beer assessed using Electron Paramagnetic Resonance Spectroscopy. The selection of strains with high resistance to multiple oxidative stresses was shown to be a good indicator that yeast would produce a more oxidatively stable beer, although the mechanisms determining this are unknown. The relevance of selecting yeast based on their oxidative sensitivity, their potential to remove metals and sulphur dioxide production are discussed. © 2021 The Authors. Journal of the Institute of Brewing published by John Wiley & Sons Ltd on behalf of The Institute of Brewing & Distilling

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Uptake and Release of Ca, Cu, Fe, Mg, and Zn during Beer Production

Cited by 30 publications

References 26 publications

Impact of Copper Fungicide Use in Hop Production on the Total Metal Content and Stability of Wort and Dry-Hopped Beer

Impact of Copper Fungicide Use in Hop Production on the Total Metal Content and Stability of Wort and Dry-Hopped Beer

On the contribution of malt quality and the malting process to the formation of beer staling aldehydes: a review

The influence of yeast strain on the oxidative stability of beer

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