Lesson 4 - Brewing Water Composition and Impact

Various cities around the world are famous for their beers. The water source (and its mineral composition) plays a large role in achieving these high quality, trademark products. It is possible to adjust your own water mineral composition to try to replicate these famous waters.

These famous cities and their associated water compositions are listed in the table below:

Table: Analysis of historical water qualities used around the world for brewing (mg/L)

This analysis gives some insight (as opposed to giving an ideal composition) into the key characteristics of each water source. For example, water used to brew lager was softer compared to the water used to brew Burton Pale Ale. But, as can be seen, the calcium levels are too low in Pilsen water as-is. Therefore, calcium is added in order to gain the typical benefits associated with calcium.

With these principles in mind, the tables below have been developed. All units are mg/L. Sodium and magnesium levels are not included as they have not traditionally been associated with these beer styles. However, sodium levels should not exceed 150 mg/L, as this can cause salty, sour and metallic flavours. Magnesium levels tend not to be higher than 15 mg/L.

It is important to note that these tables have not been verified scientifically using robust sensory analysis and therefore may only serve as guidelines. For example recent scientific work has shown that only 10 - 20 mg/L of calcium is required in wort so 75 mg/L in the brewing water would be excessive. The brewer will need to find the right mineral balance that works for their particular brand or beer style. However, the levels indicated might be helpful as a starting point.

Pale Lager

Pale lagers tend to have a balanced bitterness, so the chloride:sulphate ratio does not favour malt or bitterness. Since pale malts are used, there is no need for a high alkalinity to balance the acidity of coloured malts. 

Amber Lager

Amber lagers favour a malty profile, so the chloride:sulphate ratio is 2:1 to support malt sweetness. Alkalinity is higher to counter the acidic nature of the coloured malts.

Dark Lager

Similar to amber lager, but with a high ratio of coloured malts, there is a need for a high water alkalinity. A slightly higher calcium level helps to support the reduced amount of malt enzymes in the mash. It also helps to prevent excessive colour formation. The calcium provides a small buffer against the higher alkalinity, to ensure the mash pH does not rise excessively, even with the more acidic coloured malts.

Pale Ale

This has a low alkalinity, as low levels of coloured malts are used. It has slightly higher calcium to support bitterness extraction and buffering to alkalinity. The chloride:sulphate ratio now favours sulphate to enhance the bitterness.

Amber Ale

More coloured malts are used, which need to be balanced with alkalinity and supported with calcium. These beers tend to be highly hopped, hence the elevated sulphate and calcium levels.

Dark Ale

These beers tend to be balanced, hence the chloride:sulphate ratio. The high level of coloured malts means the waters need to be more alkaline, with some buffering from the calcium.