A drop of the soft stuff

A drop of the soft stuff

Ian Wisniewski assesses the effect of the water used in whisky production and as mixer on the drink we love

Production 16 Oct 2002 | Interviews | By Ian Wisniewski

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Explaining differences between single malts on the basis of the water used was always very convenient. Embodying a host of ecovalues, the image of a bubbling brook is far more evocative than explaining the contribution made by other factors such as the strain of yeast, the degree of reflux, the influence of copper, and, of course, maturation. The sheer volume of water in every bottle of malt whisky, with a malt bottled at 40% abv containing around 60% water, suggests that water is a primary influence. Moreover, varying water sources, whether it’s a spring, loch, stream or river, as well as the underlying geology through which the water has ‘filtered’, ensure that the nature of the water can differ enormously from one distillery to another. However, trying to determine the extent to which the water’s original characteristics remain intact during the production process, and how influential they may be in the resulting dram, is a more difficult prospect.But first, let’s recap on H2O’s opportunities: during steeping and mashing, which is referred to as the ‘process water’, and as ‘reduction water’, which is used to lower the alcoholic strength for barreling and bottling. (This is an important distinction as different criteria typically apply to the process and the reduction water).Using peaty water for steeping is often said to endow the barley with phenolic characteristics. However, attributing any phenolics directly to the water can be difficult, as even unpeated malt contains phenolic precursors (admittedly, these yield a less complex spectrum of flavours
compared to the effect of applying ‘peat reek’ to the malt).However, if peaty water does have an influence, it is also logical that this would contribute a different range of phenolic compounds compared to the influence of peat smoke. This raises another technical question, concerning solubility versus leeching: meaning the level of water soluble flavour compounds within the peaty water, as opposed to colour and solids being leeched from peat and remaining suspended, but not actually absorbed by the water, thereby making a different contribution.As most distilleries buy in malted barley, mashing is usually the first opportunity to add the individual ‘distillery water.’ Current regulations, dating from a 1998 amendment to the Private Water Supplies (Scotland) Regulations 1992, state that mashing water sourced from a private supply does not need to be of a potable standard (although the quality is still regulated and monitored). This amendment wasn't a case of revoking any previous legislation, but of providing a legal framework for a distillery to continue using the traditional water supply, and thereby avoiding any changes which may affect consistency. The fact that mashing water needn't be potable is not to suggest that inappropriate water was, or is, used for mashing, as distillers continually monitor water quality. Moreover, even if the water contained any detrimental elements (varying weather conditions, for example, can have a significant influence on water quality), double distillation prevents anything threatening from passing over into the spirit. Another important distinction, particularly for mashing, is whether the water is soft or hard. The ‘hardness’ of water is measured by the level of dissolved mineral salts, principally calcium (though other members of this gang include magnesium, iron and zinc). As the term suggests, the hardness of the water can influence the mouthfeel and flavour.While using soft water is standard in the industry, Glenmorangie is an exception, drawing hard water from natural springs a few hundred yards away. Some geologists believe this water requires about 100 years to filter through the limestone and sandstone sub-soils, before emerging laden with minerals.Calcium present in the hard water can make enzymes more efficient as catalysts for the conversion of starches to sugar during mashing. Similarly, higher calcium levels make the yeast more active, which may in turn affect the range of flavours created during fermentation, compared to the influence of soft water.Consequently, the nature of the water can have a significant influence during mashing and fermentation, particularly as the typical strength of the wash, around 8% abv, means that the remaining 92% is water.Moreover, with new make spirit typically collected at an average of around 70% abv, that still means that the balance of 30% is essentially water, accompanied by various other flavour congeners, such as esters.This raises a key issue: whether any volatile flavours from the process water survive double distillation, and actually contribute any flavour to the new make spirit. Minerals are not volatile, so that rules them out, but even if any flavours do make it through the stills, the influence would be minimal compared to the flavours resulting from the malt, yeast and the effect of distillation.New make spirit is usually reduced to 63.5% abv, which is considered the optimum barreling strength, offering a balance between the rate of maturation and the number of casks required to achieve it. Filling at a higher strength would result in the spirit interacting with the oak in a different manner, and so maturing differently.As the alcoholic strength decreases during maturation, it seems logical that water soluble flavour compounds within the oak become more readily absorbed into the spirit, which can include a range of oaky notes. Water is also a great ‘mixer’ in the sense that it helps draw together and integrate flavours.The rate of evaporation during maturation is typically stated as 2% alcohol by volume per annum. The humidity and moderate nature of the Scottish climate means that casks loose more alcohol than water. Moreover, some of the water which evaporates from the cask is offset by humidity in the air which permeates into the cask, though the loss remains greater than the gain. An obvious effect of this evaporation is a ‘concentration’ of flavours in the spirit.Reduction water (which must be potable), is often, though not always, de-mineralised for barreling, though de-mineralising is a standard process for the bottling water (which may also be drawn from a different source to the process water).De-mineralising the water entails passing it through an ion exchange column to remove various minerals, essentially ‘laundering’ the water with any original flavour characteristics virtually undetectable. This is to an extent a ‘preventative’ measure, as higher calcium levels could result in the malt whisky precipitating white crystals (visually unattractive rather than affecting the flavour, or posing any threat). Another option is to pass the water through an ultra-violet filter, which deals with any bacteria present.

Maths was never my strong point, though a little is required to compare the level and potential influence of the process water and reduction water. Here goes. If new make spirit contains around 30% water, then the reduction water for barreling accounts for around 6.5%, while reduction water for bottling would, in the case of an average 10-year-old malt, lower the cask strength of around 58% to 40% abv, giving the reduction water a similar total of around 26%. All I need to do now is try to draw a conclusion. And that depends on the degree to which the process water may or may not influence the flavour of the malt, compared to the effect of neutral, de-mineralised bottling water.Consequently, it's very difficult to quantify the extent of water's contribution to the final dram, let alone trying to relate any flavours or mouthfeel back to the original water source. The clearest consensus is that changing the water supply may affect consistency, and is, therefore, to be avoided. Would Springbank's 21-year-old, for example, be quite as magnificent if the distillery stopped using water from Crosshill Loch? We're not likely ever to know, and why take the risk.Another consideration with cask strength malts is the higher proportion of process water, compared to only a minimal amount of reduction water added for barrelling. Again, quantifying any benefits from these different proportions, and trying to undertake any taste comparisons between a malt at cask strength, and again at 40% abv with the addition of bottling water, is problematic or even redundant, the reason being that malt whisky reveals a varying repertoire of flavours at different strengths.And that brings us to the issue of the ‘final water,’ which is added to malt whisky in the glass. Diluting with still spring water (the recommended option) is typically encouraged on the basis that it ‘opens up’ the malt, which implies the existing flavours simply become more accessible. However, adding water lowers the alcoholic strength to reveal a slightly different flavour profile. Of course, if that’s how you like it, great, but I prefer to taste the malt and evaluate the texture exactly as when it was bottled, which means that my personal rule is no ‘additional’ water.Ultimately it’s difficult to reach any conclusions, except that the real debate seems to be whether the effect of water, rather than its characteristics, matters most. I look forward to hearing what you think.
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