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== Effects of magnesium ==
== Effects of magnesium ==
* '''Improved pH control''' - Magnesium beneficially lowers the [[brewing pH|pH]] during mashing by precipitating with [[phosphates]], [[protein|proteins]], and other compounds, although not as effectively as calcium because magnesium salts are much more soluble.<ref name=bsp/><ref name=hob/><ref>Eumann M, Schildbach S. [https://onlinelibrary.wiley.com/doi/10.1002/jib.18 125<sup>th</sup> anniversary review: Water sources and treatment in brewing.] ''J Inst Brew.'' 2012;118:12–21.</ref><ref name=bsp/><ref name=water/>
* '''Improved pH control''' - Magnesium beneficially lowers the [[brewing pH|pH]] during mashing by precipitating with [[phosphates]], [[protein|proteins]], and other compounds, although not as effectively as calcium because magnesium salts are much more soluble.<ref name=bsp/><ref name=hob/><ref>Eumann M, Schildbach S. [https://onlinelibrary.wiley.com/doi/10.1002/jib.18 125<sup>th</sup> anniversary review: Water sources and treatment in brewing.] ''J Inst Brew.'' 2012;118:12–21.</ref><ref name=bsp/><ref name=water/>
* '''Increased Maillard reactions''' - Magnesium promotes [[Maillard reaction]]s between sugars and amino acids, which may or may not visibly increase beer color or have an impact on flavor (this has not been well-studied).<ref name=omacha/>
* '''Increased Maillard reactions''' - Magnesium promotes [[Maillard reaction]]s between sugars and amino acids, which may or may not visibly increase beer color or have an impact on flavor (this has not been well studied).<ref name=omacha/>
* '''Improved fermentation''' - Magnesium ions are needed by many yeast enzymes, such as pyruvate decarboxylase.<ref name=salsla/><ref name=bsp>Briggs DE, Boulton CA, Brookes PA, Stevens R. [[Library|''Brewing Science and Practice.'']] Woodhead Publishing Limited and CRC Press LLC; 2004.</ref><ref name=water>Palmer J, Kaminski C. [[Library|''Water: A Comprehensive Guide for Brewers.'']] Brewers Publications; 2013.</ref><ref name=hob/><ref name=gib125/> In fact, magnesium is required for yeast growth and metabolism (fermentation).<ref name=gib125/><ref name=hob/><ref>White C. [https://www.jstrack.org/brewing/Yeast_nutrition_article.pdf Yeast nutrients make fermentations better.] White Labs. Accessed 2020.</ref> The magnesium extracted from grain typically provides the minimum amount of magnesium needed to support fermentation, although the level is usually not optimal.<ref name=gib125/><ref name=water/><ref name=salsla/> Additional magnesium in the brewing water can sometimes improve fermentation rate, including faster onset of fermentation, and can sometimes help improve yeast ethanol tolerance and improve the ability of yeast to ferment under stressful conditions, increasing sugar uptake and alcohol production.<ref name=hob10>Ryder DS. Processing aids in brewing. In: Stewart GG, Russell I, Anstruther A, eds. [[Library|''Handbook of Brewing.'']] 3rd ed. CRC Press; 2017.</ref><ref name=salsla/><ref name=gib125/> Calcium ions inhibit magnesium absorption by the yeast,<ref name=gib125/> and therefore magnesium addition may be especially useful in wort with a high calcium level (e.g. from the water or calcium salt additions).
* '''Improved fermentation''' - Magnesium ions are needed by many yeast enzymes, such as pyruvate decarboxylase.<ref name=salsla/><ref name=bsp>Briggs DE, Boulton CA, Brookes PA, Stevens R. [[Library|''Brewing Science and Practice.'']] Woodhead Publishing Limited and CRC Press LLC; 2004.</ref><ref name=water>Palmer J, Kaminski C. [[Library|''Water: A Comprehensive Guide for Brewers.'']] Brewers Publications; 2013.</ref><ref name=hob/><ref name=gib125/> In fact, magnesium is required for yeast growth and metabolism (fermentation).<ref name=gib125/><ref name=hob/><ref>White C. [https://www.jstrack.org/brewing/Yeast_nutrition_article.pdf Yeast nutrients make fermentations better.] White Labs. Accessed 2020.</ref> The magnesium extracted from grain typically provides the minimum amount of magnesium needed to support fermentation, although the level is usually not optimal.<ref name=gib125/><ref name=water/><ref name=salsla/> Additional magnesium in the brewing water can sometimes improve fermentation rate, including faster onset of fermentation, and can sometimes help improve yeast ethanol tolerance and improve the ability of yeast to ferment under stressful conditions, increasing sugar uptake and alcohol production.<ref name=hob10>Ryder DS. Processing aids in brewing. In: Stewart GG, Russell I, Anstruther A, eds. [[Library|''Handbook of Brewing.'']] 3rd ed. CRC Press; 2017.</ref><ref name=salsla/><ref name=gib125/> Calcium ions inhibit magnesium absorption by the yeast,<ref name=gib125/> and therefore magnesium addition may be especially useful in wort with a high calcium level (e.g. from the water or calcium salt additions).
* '''Improved yeast flocculation''' - Magnesium ions can positively influence flocculation, substituting for calcium.<ref name=gib125/> This effect can be inhibited by the presence of metal-chelating agents (i.e. [[tannin additives]]) since magnesium is more sensitive to chelation than calcium.
* '''Improved yeast flocculation''' - Magnesium ions can positively influence flocculation, substituting for calcium.<ref name=gib125/> This effect can be inhibited by the presence of metal-chelating agents (i.e. [[tannin additives]]) since magnesium is more sensitive to chelation than calcium.

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Magnesium periodic table emblem

Magnesium (Mg2+) is a mineral naturally present in water and grain. It is one of the most important ions for fermentation performance.[1] Magnesium is required for the function of over 100 enzymes, making it a necessary nutrient for yeast growth and fermentation.[2] Magnesium is also an important component of beer flavor, imparting a lightly sour and astringent or bitter character. However, as the level of magnesium increases, the flavor may become unpleasant. At excessive levels (higher than 125 mg/L in beer), magnesium can have possible diuretic or laxative effects, although the latter is unlikely.[3][4] To avoid any negative effects, it is suggested to have no more than 20–40 mg/L magnesium in the brewing water.[5][4][3] The presence of some magnesium in the brewing water is widely considered to be beneficial, although there is no consensus on the ideal amount.[3][6] Magnesium behaves similarly to calcium, and the effects of these two ions have some interesting interactions.[3]

Potential sources of magnesium

  • Brewing water - The water used to make beer may contain dissolved magnesium.
  • Grain - Magnesium has high extractability compared to that of other metals, up to 80%.[1] A typical wort provides around 50–90 mg/L magnesium extracted from the grain,[1][3] although a large portion may be bound to organic molecules (limiting the amount available to the yeast).[2] The magnesium content of grain can vary widely, probably due to fertilizer usage.[7]
  • Salt additives - Brewers can enrich the magnesium level of the wort by adding brewing salts that contain magnesiumm, such as magnesium chloride or magnesium sulfate.

Almost all of the magnesium in the water and extracted during mashing is present in the final beer. Standard strength commercial beers contain magnesium concentrations from around 60–150 mg/L.[7]

Effects of magnesium

  • Improved pH control - Magnesium beneficially lowers the pH during mashing by precipitating with phosphates, proteins, and other compounds, although not as effectively as calcium because magnesium salts are much more soluble.[4][8][9][4][3]
  • Increased Maillard reactions - Magnesium promotes Maillard reactions between sugars and amino acids, which may or may not visibly increase beer color or have an impact on flavor (this has not been well studied).[7]
  • Improved fermentation - Magnesium ions are needed by many yeast enzymes, such as pyruvate decarboxylase.[2][4][3][8][1] In fact, magnesium is required for yeast growth and metabolism (fermentation).[1][8][10] The magnesium extracted from grain typically provides the minimum amount of magnesium needed to support fermentation, although the level is usually not optimal.[1][3][2] Additional magnesium in the brewing water can sometimes improve fermentation rate, including faster onset of fermentation, and can sometimes help improve yeast ethanol tolerance and improve the ability of yeast to ferment under stressful conditions, increasing sugar uptake and alcohol production.[5][2][1] Calcium ions inhibit magnesium absorption by the yeast,[1] and therefore magnesium addition may be especially useful in wort with a high calcium level (e.g. from the water or calcium salt additions).
  • Improved yeast flocculation - Magnesium ions can positively influence flocculation, substituting for calcium.[1] This effect can be inhibited by the presence of metal-chelating agents (i.e. tannin additives) since magnesium is more sensitive to chelation than calcium.
  • Flavor - At the moderate levels typically found in wort, magnesium can enhance a beer's character by providing a mild sour or bitter astringency.[3][11][8][4][12][6] At excessive levels, the sour and bitter notes can become unpleasant and harsh.[3][13] These flavor effects appear to depend on a balance between the magnesium and calcium ions, since calcium can reduce the flavor impact of magnesium.[8] Magnesium increases humulone isomerization (hop utilization), which may contribute to the bitter flavor of magnesium.[7]

How to adjust the magnesium level

In order to ensure a good fermentation, the addition of some magnesium to brewing water may be desirable.[5] While magnesium sulfate (e.g. Epsom salt) is a common traditional option, magnesium chloride is also a good option for adding magnesium if you would prefer to minimize that amount of sulfate. Magnesium content in yeast extracts (i.e. yeast nutrient products) can also improve the fermentation performance of yeast, although adding a magnesium salt might be more beneficial.[1] When considering the potential of magnesium to improve yeast fermentation performance, the concentration of wort calcium should also be taken into account.[1] Calcium competes with magnesium for uptake by the yeast, and any observed improvement may be related to the Mg:Ca ratio rather than the absolute concentration of magnesium.[1]

If the magnesium level in your tap water is too high, the only option to decrease it for use as brewing water is to purify it with a reverse osmosis system. Yeast can theoretically absorb a maximum of 30–45 mg/L of magnesium during a typical fermentation, which can help to mildly lower the amount in the final beer.[2]

See also

  • Water - Expert guide to adjusting water minerals
  • Brewing pH - Discussion of pH throughout the brewing process, including the benefits of pH control by adjusting calcium.

Potential sources

References

  1. a b c d e f g h i j k l Gibson BR. 125th anniversary review: improvement of higher gravity brewery fermentation via wort enrichment and supplementation. J Inst Brew. 2011;117(3):268–284.
  2. a b c d e f Saltukoglu A, Slaughter JC. The effect of magnesium and calcium on yeast growth. J Inst Brew. 1983;89(2):81–83.
  3. a b c d e f g h i j Palmer J, Kaminski C. Water: A Comprehensive Guide for Brewers. Brewers Publications; 2013.
  4. a b c d e f Briggs DE, Boulton CA, Brookes PA, Stevens R. Brewing Science and Practice. Woodhead Publishing Limited and CRC Press LLC; 2004.
  5. a b c Ryder DS. Processing aids in brewing. In: Stewart GG, Russell I, Anstruther A, eds. Handbook of Brewing. 3rd ed. CRC Press; 2017.
  6. a b Comrie AA. Brewing liquor—a review. J Inst Brew. 1967;73(4):335–346.
  7. a b c d Omari IO, Charnock HM, Fugina AL, Thomson EL, McIndoe JS. Magnesium-accelerated Maillard reactions drive differences in adjunct and all-malt brewing. J Am Soc Brew Chem. 2021;79(2):145–155.
  8. a b c d e Taylor DG. Water. In: Stewart GG, Russell I, Anstruther A, eds. Handbook of Brewing. 3rd ed. CRC Press; 2017.
  9. Eumann M, Schildbach S. 125th anniversary review: Water sources and treatment in brewing. J Inst Brew. 2012;118:12–21.
  10. White C. Yeast nutrients make fermentations better. White Labs. Accessed 2020.
  11. Howe S. Raw materials. In: Smart C, ed. The Craft Brewing Handbook. Woodhead Publishing; 2019.
  12. Habschied K, Košir IJ, Krstanović V, Kumrić G, Mastanjević K. Beer polyphenols—bitterness, astringency, and off-flavors. Beverages. 2021;7(2):38.
  13. Fix G. Principles of Brewing Science. 2nd ed, Brewers Publications; 1999.