Chalky and minerally finishes that come from brewing water

Water is most of what you drink

A typical beer is more than 90% water. Whatever was dissolved in that water at the start, plus anything the brewer added, ends up in your glass. Most of it you never notice. When minerals are out of balance, though, they show up in the finish: a dry, chalky feel, a salty edge, a mineral or metallic tang or a bitterness that lingers too long.

Brewers talk about six main ions in water: calcium, magnesium, sodium, sulphate, chloride and bicarbonate. Each has a recognisable effect. You do not need chemistry to taste them, just a little attention to the last few seconds of each sip. Our guide to brewing water basics covers the chemistry side.

Sulphate: dry and firm

Sulphate makes hop bitterness feel drier, firmer and longer. In moderation it gives an IPA its crisp, snappy finish. Classic Burton-on-Trent water, famous for pale ales, is very high in sulphate. Brewers who copy it add gypsum (calcium sulphate). Taken too far, the finish becomes harsh, minerally and slightly chalky and bitterness hangs on the palate.

Brewers often discuss the balance of sulphate to chloride. More sulphate pushes a beer dry and bitter. More chloride pushes it round and full. Our guide to the sulphate to chloride ratio explains how brewers use it.

Calcium and bicarbonate: chalky

Calcium is the brewer's friend. It helps enzymes in the mash, helps yeast settle and drops out oxalate that would otherwise cause haze and gushing. Typical brewing targets sit around 50 to 150 mg/L. It does not taste of much on its own.

Bicarbonate, the alkaline part of hard water, is different. It raises mash pH, which can make pale beers taste dull and harsh. When a brewer adds chalk (calcium carbonate) to water for a dark beer and some of it fails to dissolve, or when very hard water goes untreated, the finish can feel literally chalky. Many Indian borewells deliver hard, high bicarbonate water. Brewers on that supply usually treat it before brewing pale beers.

Magnesium and sodium: sour, salty, harsh

Magnesium is a yeast nutrient in small amounts. Above about 30 mg/L it starts to taste sour and bitter, so brewers keep it modest, usually in the range of 10 to 30 mg/L. Sodium at low levels rounds out malt sweetness, which is why gose, a salted style, works. In most beers, though, sodium above roughly 100 to 150 mg/L reads as salty or harsh. Water softened with an ion exchange softener swaps calcium for sodium, which is a common way for a brewery to end up with salty beer by accident.

Why the same beer tastes different in two cities

India is a good place to see water at work. Municipal supply in one city may come from a river or reservoir and be fairly soft. A few hundred kilometres away a brewery may rely on deep borewells with high hardness, high bicarbonate and sometimes a fair amount of sodium. Many breweries also switch to tanker water in the dry months and tanker water can change from one load to the next.

A brewery that does not treat or test its water can make the same recipe in March and May and get two different finishes. That is why many brewers now strip their water back with reverse osmosis and add back measured amounts of gypsum and calcium chloride. It turns water from a variable into a recipe ingredient. If a favourite local beer suddenly tastes drier or saltier one month, a change in the water supply is a fair guess.

How to taste the minerals

Next time you drink a beer, pay attention to the last few seconds:

• Dry, firm, bitterness lingers: likely sulphate.
• Round, soft, fuller: chloride.
• Chalky, dusty, dull: hardness and bicarbonate.
• Salty, slightly brackish: sodium.
• Sour metallic edge: magnesium or iron.

A useful comparison is two waters. Pour a glass of a soft bottled mineral water and one of a hard mineral water, read the labels and taste them side by side. The hard one usually has a drier, chalkier finish. Beer magnifies that difference.

When mineral character belongs

Not all minerality is a fault. A Burton style pale ale is meant to finish dry and firm. A Dortmunder export lager sits on harder water than a Pilsner and tastes that way. Gose carries a gentle saltiness on purpose. A soft, round Czech Pilsner, by contrast, should taste almost mineral free. The question is whether the mineral character suits the beer. A delicate lager with a chalky finish is out of balance. A Burton pale ale without one is missing something.

Your first step: buy two bottled mineral waters with very different mineral figures on the label, taste them side by side, then taste your next beer with that finish fresh in your mind.

Common questions

Why does my beer have a chalky finish?

Usually high hardness and bicarbonate, undissolved chalk or excess sulphate in the brewing water.

What does sulphate do to beer?

It makes hop bitterness feel drier, firmer and longer. In excess it gives a harsh, minerally finish.

Can brewing water make beer taste salty?

Yes. Sodium above roughly 100 to 150 mg/L can taste salty and water softened by ion exchange often carries extra sodium.

Is mineral character ever intended?

Yes. Burton pale ales, Dortmunder lagers and gose all carry mineral or salty character as part of the style.