How much water does it take to make a bottle of whisky?

The water goes to five places: mashing, diluting the wash, cooling the condensers, cleaning the plant, and reducing to bottling strength.

During mashing, hot water is poured over ground malt to release the fermentable substances. The mash is then brought down with water to the strength at which the yeast can work. After distilling, water is added again before the spirit goes into the cask, and once more at the end to bring the whisky to the strength on the label. Cleaning water for the stills, the washbacks and the pipes runs alongside all year round.

However, most of the water never comes near the whisky: cooling water for the condensers turns the alcohol vapor back into liquid and leaves the plant without touching the product. According to 2019 SEPA figures, cited in the research programme DWR UISCE, 80 percent of the water that Scottish distilleries abstract is cooling water.

Process water ends up in the whisky or evaporates; cooling water never touches the product and, after use, largely returns to the stream or river it came from.

In the SEPA figures for 2019, cited by the research programme DWR UISCE, Scottish distilleries account for 70 percent of all licensed direct water abstractions by industrial and commercial users. Of that water, 80 percent is cooling water. An abstraction of hundreds of cubic metres a day therefore says little about how much water is actually taken from the region.

SEPA also takes that distinction into account in its rules. The drought guidance states that abstractions where the water is returned nearby do not qualify for suspension: within 500 metres in water bodies with high status, and within 1,500 metres elsewhere, as long as there is no significant effect. Anyone who loses the water to evaporation or to the product does not fall under this.

A bottle of 70 centilitres at 40 percent contains 28 centilitres of pure alcohol and about 42 centilitres of water; at 60 percent that is 42 and about 28 centilitres.

The difference is therefore a good fourteen centilitres of water per bottle. Anyone who bottles the same whisky at 40 percent instead of 60 percent also needs less spirit per bottle: 46.7 centilitres at 60 percent plus 23.3 centilitres of water gives exactly 70 centilitres at 40 percent. Those 23.3 centilitres are the bottling water, and that is the only water in this whole story that you actually find again in your glass.

Calculated the other way round, one litre of pure alcohol fills about 3.6 bottles of 70 centilitres at 40 percent, and about 2.4 bottles at 60 percent. Cask strength whisky gets no more water added at bottling. The lower limit is laid down by law: the Scotch Whisky Regulations 2009 require at least 40 percent alcohol and, besides water, allow only plain caramel colouring.

Abstraction is not free: above 50 cubic metres per day SEPA requires a licence, and in dry summers those licences are temporarily restricted.

Scotland works with three tiers. Below 10 cubic meters per day, general rules apply; between 10 and 50 cubic meters per day, the abstraction must be registered; and above that a licence is required. Abstractions of up to 10 cubic meters per day may also continue during a period of scarcity.

That the restrictions really bite became clear in 2025. On 11 September, 17 catchments were at the Significant Scarcity level, the highest number since the introduction of the current National Water Scarcity Plan, including the Lower Spey, the Deveron, the Findhorn and the Lower Dee. SEPA issued roughly 270 restrictions on abstraction licences that year, by its own account the highest number ever.

Water efficiency in the Scottish whisky industry has improved by 22 percent since 2012, and since the summer of 2023 there has been a Water Stewardship Framework for consumption per distillery.

The Scotch Whisky Association measures in litres of water per litre of pure alcohol and, in its 2021 Sustainability Strategy, set a target range of 12.5 to 25 l/lpa for 2025, depending on the size of the distillery and on what is being distilled. The range is reviewed every two years; the trade association has announced that it will set stricter targets after that.

Where the gains lie has been mapped at Arbikie in the DWR UISCE research programme. Routing the cooling water differently and recovering the heat from it can reduce abstraction by up to 45 percent. Using the draff and pot ale as animal feed instead of imported soy meal offsets up to 47 percent of the water scarcity footprint.