It might not seem that important to people who are unfamiliar with industrial processes. “Just take some tap water and throw it in with the other ingredients” you might say. Unfortunately it’s not that easy. Water as we know it, bottled or from the tap, contains a lot of “contaminants” for usage in industrial processes. Beer contains 90% water and to make 1 litre of beer you need approximately 3 litres of water. There are two ways of retrieving water for brewing purposes. Surface water from lakes, rivers,…; and groundwater, which is pumped up from below the surface. Old breweries were often built on top or near a place where they pumped the water from the ground for direct usage and minimum transport costs. Nowadays this isn’t necessary any more as water is corrected to a constant quality and to the norms of the brewery.
The choice of water affects the beer in three different ways: It affects the pH which affects the flavour of the beer as it activates different types of taste buds on the tongue, the water’s sulfate to chloride ratio ‘seasons’ the beer and chlorine and other contaminants can cause unwanted, bad tasting flavours.
The main ‘evildoers’ in water are ions (iron, calcium, sulphate,…). If interested you can click here to find out about the effect of every ion on the beer’s taste as it’s too elaborate to explain it all in this dense blog post. There are two types water, soft and hard; both can be used to brew beer. The unit of water hardness is ‘French Degrees’ or °FD and the difference between the two is the quantity of Calcium and Magnesium ions.
The used water goes through a series of processes before it can be used in the final product. It needs to be de-ironed, decarbonised, demineralised, sterilised and degassed. There are different methods for each step depending on the preferences of the brewer, available space (for the necessary machinery), cost of the investment, danger,…
The most important process is degassing. This is the process where oxygen is eliminated from the solution. The amount of oxygen in water is often mentioned as dissolved oxygen (DO) in mg/l or ppm (parts per million). For beer the maximum amount is 0,02 mg/l. The reason for this is that oxygen oxidises beer. Oxidization is the cause of stale flavours as molecules in the beer undergo a chemical reaction with oxygen.
There are two ways of degassing water. The first method is vacuum degassing where the beer is brought into an environment with low pressure so that oxygen spontaneously leaves the beer. Another method is pressure degassing where the beer is placed in a keg with pressurized carbon dioxide or nitrogen so that the oxygen is pushed away by the pressurized gasses.
Now you might wonder, “if beer contains 90% water then can’t I just give up on drinking boring water and drink beer as a substitute”? How wonderful (and perhaps a bit alcoholic) that might sound you wouldn’t last very long. Alcohol has a diuretic effect causing the net balance of the water intake and the alcohol’s diuretic effect to be negative meaning you’d dehydrate.
We’ve all suffered from hangovers. The reason why you have feel so bad after a night of drinking is because of dehydration. Thus, depending on the alcohol percentage, you’d only last for a couple of days. Sorry to break it to you but at least you now know it’s not worth the try.
Now go grab yourself a glass of beer (or water) and I’ll you next time, cheers!
~Blancke The Brewer