Sulfate

From Brewing Forward

Sulfate (SO42–) is an ion naturally present in water, and including any brewing salts added, it is the main source of sulfate in wort. In beer, sulfate ions add dryness, accentuate the bitterness of hops, and lend a crisp finish to the beer. The dryness/sweetness balance of the beer is likely affected by not just the concentration of sulfate, but also the ratio of the sulfate to chloride ions.[1] Brewing literature suggests a wide range of maximum levels for sulfate in the brewing water, up to 500 ppm (mg/L).[2][3][4] This is likely because the desirable level of sulfate depends on the style of beer,[5] the relative level of chloride ions present, and personal preference. Sulfate is absorbed to a limited extent by yeast cells during fermentation, and can facilitate sulfite formation.[5][6]

Sulfate should not be confused with sulfite or sulfide.

Beer sulfate content: The level of sulfate in commercial beer is typically around 150 to 200 mg/L, although it can range to over 400 mg/L based on variability in the water and the brewer's preference.[7][8]

Potential sources of sulfate[edit]

The sulfate content in beer comes from the raw ingredients, mainly the water, plus any salts added by the brewer.

  • Brewing water - Sulfate levels in tap water can range up to 600 mg/L, although most fresh water contains less than 100 mg/L.[9][10]
  • Grain - A very small amount of sulfate is extracted from the malt during mashing, around 5 mg/L.[2]
  • Salt additives - Brewers often add sulfate salts to modify the flavor balance of the beer, depending on the style of beer and personal preference. Calcium sulfate and magnesium sulfate are commonly used for this purpose. If sulfite is used during mashing (i.e. low oxygen brewing), it will oxidize, adding a small amount of sulfate to the beer.

Effects of sulfate[edit]

  • Flavor - In relatively moderate amounts (200-400 ppm), sulfate ion has a dry and bitter effect on the palate.[11][12][2][13][3][6] This effect can be used to accentuates hop bitterness, making the bitterness seem drier and more crisp.[2] At higher levels, the resulting bitterness can become harsh, astringent, and unpleasant.[2] Chloride ion can be used to help balance the dryness of sulfate.[3][1][5] Many Czech and German lager brewers avoid sulfates entirely, because they find that it ruins the soft noble hop character of Pils and Helles style beers.[2] High sulfate levels may also be undesirable in dark beers.[14] Lastly, sulfate is more likely to impart an unpleasant harshness when combined with higher levels of sodium. Therefore, the more sulfate there is in the water, the less sodium there should be (and vice versa).[5]
  • Improved starch and protein degradation - Sulfates positively affect protein and starch degradation, which favors mash filtration and trub sedimentation.[5]
  • Decreased hop utilization - If the sulfate levels are too high, it may result in poor hop utilization (bitterness will not easily be extracted).[5]

How to adjust the sulfate level[edit]

Brewers may wish to add sulfate to the brewing water in the form of calcium sulfate or magnesium sulfate, depending on whether calcium or magnesium are desired. Sulfate is also a product of the metabisulfite salts used for low oxygen brewing. See Water for our guide to adjusting water minerals and mash pH.

If the sulfate level in your water is too high, purification by reverse osmosis filtration is a good option to remove practically all sulfate ions and other minerals so that the water mineral profile can be built from scratch.

See also[edit]

References[edit]

  1. ↑ a b Howe S. Raw materials. In: Smart C, ed. The Craft Brewing Handbook. Woodhead Publishing; 2019.
  2. ↑ a b c d e f Palmer J, Kaminski C. Water: A Comprehensive Guide for Brewers. Brewers Publications; 2013.
  3. ↑ a b c Briggs DE, Boulton CA, Brookes PA, Stevens R. Brewing Science and Practice. Woodhead Publishing Limited and CRC Press LLC; 2004.
  4. ↑ Krottenthaler M, Glas K. Brew water. In: Esslinger HM, ed. Handbook of Brewing: Processes, Technology, Markets. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA; 2009.
  5. ↑ a b c d e f Montanari L, Mayer H, Marconi O, Fantozzi P. Chapter 34: Minerals in beer. In: Preedy VR, ed. Beer in Health and Disease Prevention. Academic Press; 2009:359–365.
  6. ↑ a b Eumann M. Chapter 9: Water in brewing. In: Bamforth CW, ed. Brewing: New Technologies. Woodhead Publishing; 2006:183–207.
  7. ↑ Kunze W. Hendel O, ed. Technology Brewing & Malting. 6th ed. VLB Berlin; 2019:711.
  8. ↑ Buiatti S. Chapter 20: Beer Composition: An Overview. In: Preedy VR, ed. Beer in Health and Disease Prevention. Academic Press; 2009:213–225.
  9. ↑ Platikanov S, Hernández A, González S, Cortina JL, Tauler R, Devesa R. Predicting consumer preferences for mineral composition of bottled and tap water. Talanta. 2017;162:1–9.
  10. ↑ Burlingame GA, Dietrich AM, Whelton AJ. Understanding the basics of tap water taste. J Am Water Works Assoc. 2007;99(5):100–111.
  11. ↑ Taylor DG. Water. In: Stewart GG, Russell I, Anstruther A, eds. Handbook of Brewing. 3rd ed. CRC Press; 2017.
  12. ↑ Comrie AA. Brewing liquor—a review. J Inst Brew. 1967;73(4):335–346.
  13. ↑ Eumann M, Schildbach S. 125th Anniversary review: Water sources and treatment in brewing. J Inst Brew. 2012;118:12–21.
  14. ↑ Fix G. Principles of Brewing Science. 2nd ed. Brewers Publications; 1999.
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