Originally spelt “Cardow”, Cardhu distillery was established by a notorious whisky smuggler who had decided to go straight following the introduction of the Excise Act regulating taxation on whisky production in 1824. In the 1880s it attracted the attention of one John Walker, who used much of the distillery's malt to provide for his increasingly popular blend: it remains a core ingredient in most Johnnie Walker blends today, with about 70% of the distillery’s production being swallowed up by this behemoth.
More recently, Cardhu has become a very popular single malt in Southern Europe, particularly Spain and Portugal. Demand for the product was so huge in these countries that Cardhu’s parent company Diageo replaced the 12-year-old single malt with a “Pure Malt” expression, which was actually a blended malt marketed under the Cardhu name. Such was the outcry from whisky producers and drinkers, concerned that the integrity of the “single malt” term would be harmed, that Diageo later withdrew the “Pure Malt” and reinstated the 12-year-old.