Single Pot Still (SPS) is a style of whiskey entirely unique to Ireland. The essential feature of SPS whiskey is that whereas single malt whisky is made entirely from malted barley, single pot still whiskey is triple-distilled from a mixture of both malted and unmalted 'green' barley. This gives it a distinctive spicy, cereally flavour often referred to as 'potstill character' and a rich, silky texture. Until recently, single pot still whiskey was known as 'pure pot still'. In 2011, however, this term was changed to 'single pot still' to comply with UK and US labelling regulations.
All the single pot still whiskey currently made in Ireland is distilled at the Midleton distillery, where it is used as the base for several of the island's biggest blends. Ireland's most famous whiskey, Jameson, is a mixture of single pot still whiskey and grain whiskey, both of which are produced at Midleton. However, until recently Midleton only bottled two single pot still whiskies: Redbreast 12 year old and Green Spot.