Water makes up the largest percentage of a finished beer. The ratios of different dissolved mineral ions in water can significantly alter the flavor and aroma of the finished beer. Water plays a significant role in most of the brewing processes including mashing, hop utilization during boiling and yeast performance during fermentation.
Brewing water is usually categorized using a profile of Calcium (Ca), Sulfate (SO4), Sodium (Na), Chloride (Cl), Carbonate (CO3) and Magnesium (Mg) ions. In addition the overall alkalinity (carbonates and Bi carbonates)becomes important when mashing for pH control in all-grain brews.
The principal ions are:
- Calcium (Ca) - Aids in mashing and yeast growth if used in moderation. Should be kept to the 80-100 ppm range for mashing and sparging. Ca is the major ion responsible for mash acidification. The process is calcium ions react with phosphates in malt creating calcium phosphate and hydrogen ions. An increase in Hydrogen ion concentration reduces pH and is "buffered'by the presence of Bicarbonates and carbonates therefore sufficient calcium ions need to be present to overcome the buffering to reduce pH to correct mash pH of 5.2 to 5.6
- Sulfate (SO4) - in the form of Calcium Sulphate for adding calcium if the water is deficient in sulfate and is used to add sulfate "crispness" to hop bitterness.
- Sodium (Na) - Helps to accentuate sweetness of malt at levels below 100 ppm. Generally should be kept to a low to moderate level as high levels are associated with sour, salty tastes.
- Chloride (Cl) - Accentuated flavor of beer when kept below 100 ppm for light beers or a max of 300 ppm for dark beers. Can result in bleach or medicine flavor if raised too high.
- Carbonate/Bicarbonate (HCO3) - An alkaline buffering agent that raises the pH of the mash, reducing acidity. Contributes to bitterness, darker color and extraction of tannins during the mash.
- Magnesium (Mg) - Secondary source of hardness. Needed in small amounts (10-30 ppm) for yeast growth and better beer flavor. Overuse (anything > 50) can create astringency.
Water and Beer Styles
The most famous styles for a given city are typically closely tied to the water available. For example, the famous Pilsner style originated in the city of Pilsen, Czech Republic. Their soft water has very low levels of all minerals, which aids in producing a pale color lager with clean bitterness. Similarly the high levels of calcium, carbonate and sulfate of Burton on Trent's hard water in the UK help produce unique hoppy English pale ales. For examples of some brewing waters from around the world, see the hops table in the external links below.
German Brewers of old employed an acid rest to acidify the mash, as, due to insufficient calcium ions in the low mineral content water, the mash would not reach the desired pH. The acid rest allowed enzymatic phytase activity and in no small part bacterial activity and growth to acidify mash. The low mineral content water in Dublin was overcome by the addition of highly roasted acid malts and of course made beer quite dark!. Burton water that is high in calcium ions meant that an acid rest was not needed and a single infusion mash is all that was required. Malting technology in the past meant that a percentage of the kilned malt was burnt producing the acidity required such malt was also often poorly modified. Better technology lead to lighter kilned malts great for light lager, but required an acid rest in low calcium waters.
Water adjusting goals
When thinking of water chemistry for brewing there are 2 seperate considerations. Firstly, and most importantly, that the dissloved ion profile (mostly Ca ions) be condusive to attaining the correct mash pH in the range of 5.2-5.6. Secondly that dissolved ion concentrations A. Not have a negative flavour impact and B. Where required have a positive or desired flavour contribution. It is no point obsessing over the optimal Sulphate to Chloride ion ratio if excessive tannins are extracted due to a high pH mash!
You can add minerals to your water to adjust the alkalinity for mashing and also to add minerals for flavor complexity. The most popular additives are Calcium sulphate (CaSO4)commonly gypsum flour, Calcium carbonate (CaCO3)chalk powder, Calcium Chloride (CaCl), Sodium Chloride (NaCl)salt the non iodised type, Sodium bicarbonate(NaHCO3)Baking Soda and Magnesium sulphate(MgSO4)or epsom salts. Carbonates can be used to reduce or buffer the alkalinity of the mash. Brewing software or a water calculation tool can help you determine the correct amount of additives to use. It should be noted that calcium carbonate is very insoluable in water.
- Brewing Water Reference Table
- [Insert water profile links here]
- BeerSmith Water Reference Table - waters from around the world.