Of all the ingredients in beer the contribution of the brewing water is often overlooked. Many cities renowned as a hub for beer have the type of water available in the area to thank for their characteristic flavor profile.
Dublin is known for its dry stouts. The water in Dublin is ideal for use with dark malts.
Burton-Upon-Trent in the UK gained renown for its (India) Pale Ale in the 19th century. The local water accentuates hop aromas.
Pilsener literally means “from Plzeň” in the Czech Republic. The pure water of that region is perfect for pale malts and noble hops.
But what do we mean when we say “type” of water? For beer there are two important characteristics: dissolved minerals and alkalinity.
Which and how much of a particular mineral is dissolved in the brewing water has a big effect on the experience of a beer’s taste. Minerals in water dissolve into ions and different ions can have a different effect on the beer.
Calcium ions help precipitate proteins that can make a beer hazy and may also help yeast flocculate (clump up and sink). To an extent, increased calcium results in a clearer beer. Calcium also helps out in the mash by stabilizing enzymes.
Magnesium ions are an important nutrient for yeast. Luckily, malt contains more than enough to ensure healthy growth of the yeast. Too much magnesium can result in a nasty acidic and bitter off-flavor.
Sulphate ions can raise the perception of hops and give a dry mouthfeel. The amount of sulphate also has an effect on how long the bitterness can linger. Interestingly, really high concentrations can have a negative effect on the bitterness.
Chloride ions give beer a rounder, fuller, maltier character. Unfortunately, chloride is corrosive so high concentrations are bad for brewing equipment.
The ratio between sulphate and chloride ions is important for the hop-malt and dry-full balance of a beer.
Alkalinity overlaps with acidity, more alkaline water contains more carbonate which can neutralize more acid. This is important for brewers because dark malts turn out to be more acidic and too much acid can make a beer feel thin. So in order to brew a full-bodied malty beer it is important to take note or compensate the water’s alkalinity.
It’s possible to adjust the alkalinity and minerals of the brewing water. By adding specific kinds of brewing salts a brewer can exert direct control over both. Unfortunately the math for adding salts and the resulting concentrations are somewhat tricky. For instance, adding 1 gram of chalk (calcium carbonate) does not raise the calcium concentration by 1 gram. This is because only part of the weight of the chalk consists of calcium. Furthermore, the bad solubility of chalk has to be taken into account. Specific calculations are beyond the scope of this post but to learn more we recommend Water – A Comprehensive Guide for Brewers by John Palmer and Colin Kaminski.
Taste the effect
If you want to taste the effect of modifying water, try our Kveik Pale Ale for which we adjust the alkalinity of our brewing water to give it a fuller mouthfeel. Not because of the malts in this case but because Kveik is prone to acidify beer a little bit.