Water can make up about 90% of a regular beer’s composition, yet it is not the only reason why this compound is so vital for the brewing industry. Water is used all around a brewery, serving multiple purposes: such as cleaning (regular CIP processes and normal surface and facility cleaning), different cooling purposes (such as heat exchange during various brewing processes and acting as a pump and conveying system coolant), heating (steam generation) and the most obvious, the base and core of beer.
First of all, as it may intrigue quite a few people, during beer brewing (and mainly recipe development) it is really crucial to keep an eye on the water’s mineral profile to ensure the higher quality of beer. Focusing on each one of the main compounds (that will be referred to as ions from now on) present in water will give the brewer a better understanding and better grip on how to boost flavor profiles regarding the finished product. The main ions to be discussed are Calcium (Ca+2), Magnesium (Mg+2), Sulfates (SO4-2), Chloride (Cl-) and bicarbonates (HCO3-).
Calcium could be considered a multi-tasking agent in every step of the brewing process. First, this ion is the main source of hardness in water. It acts – during mashing – as a catalyst and heat protection for enzymatic reactions (decreasing the mash pH, that will help reaching optimal enzymatic activity; proteolytic activity, helping on the Free Amino Nitrogen content for fermentation and reducing long chain proteins, aiding filtration and final product shelf life), during boiling and fermentation as a sedimentation agent (promoting protein-protein and protein-polyphenols coagulation, oxalic acid reaction to insoluble calcium oxalates, yeast flocculation). The sole negative effect of calcium is decreasing the pH value of the mash and wort, which ultimately decreases the hop utilization, but the effect is insignificant compared to the benefits.
Magnesium, as the second source of hardness in water, has an important role during fermentation due to its role as a catalyst for some metabolic processes of yeast. However,its concentration must be closely controlled and monitored due to some side effects; if it exceeds the amount that is deemed necessary, the high amount of magnesium may act as a laxative and impart bitter flavors to the beer. Sulfates and chlorides, and mainly their ratio, will help lead the beer to a bitter or a malty profile. If the ratio between these two ions is inclined to the sulfates, the beer will have a drier and clean, bitter taste (for instance: 2:1 for sulfates). On the other hand, if the ratio is inclined to the chlorides (exactly the same ratio, 1:2) the beer will impart a more full-bodied, malt-rich taste. Depending on the desired profile of the finished beer, playing with the mineral profile could be an improvement for the following brews!
Last, but not least, bicarbonates. The main ion referred to when discussing alkalinity. The importance of it regarding water chemistry is sometimes overlooked. Practically, this ion is responsible for the buffering effect in water. As mentioned above in regards to the calcium, decreasing the pH value is desired to enhance different, efficient effects for the process, but the bicarbonates will neutralize this and will try to maintain the pH of the solution, mash or wort, even green beer. It is the brewer’s task, depending on the beer style and profile to be given to the final product, to appropriately approach the bicarbonate content of the beer. For example, in the case of light beers, where there are not that many dark malts promoting acidification (due to the presence of Maillard products, which are considered acidity providers) low bicarbonate concentration would be beneficial to adjust the pH values with ease. For darker beers, such as porters or stouts, a higher concentration of bicarbonate will buffer – to some extent – the effect of darker malts and will balance the flavors of the finished product.
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