Production

The C Words

In the latest in his series defining whisky terms Dominic Roskrow looks at the letter C
By Dominic Roskrow
Barley, yeast and water may be whisky’s raw ingredients and the skill of the whisky maker and distiller may be crucial in placing the foundations of a great single malt. But it is two c words which steer the new make spirit towards its final taste destination – casks and charring.Whisky of all types has to be made in oak barrels and there are two principle sources – American oak and European oak. The vast majority are American and are used first for bourbon and then passed on to distilleries in Scotland, Ireland, Japan and elsewhere.Under American law, a cask may only be used for whiskey production once and then it must be discarded. For this reason there is a ready supply of cheap bourbon barrels – they cost about one tenth the price of a European sherry cask.Before an American cask can be used for American whiskey it will be charred. There are different grades of charring from a light toasting to a deep and heavy burning. The process releases vanillin in the wood and helps expose the liquid contents to tannins, wood extractives, hemicellulose and lignin.It is from these that a complex set of chemical reactions takes place.In broad terms three things happen: the wood gives the whiskey its colour and up to 80 per cent of its flavour; the wood extracts some flavours and impurities from the whiskey. And the whiskey and the wood react together to form new flavours.When the cask is emptied of American whiskey and sent to a country such as Scotland to be filled with new make single malt the previous contents will have soaked in to the wood and will have an influence on the new contents. But the chemical reactions witnessed when the cask was originally used will also continue to take place.Each successive time the cask is filled – and it may be used a few times – the wood’s effect on the whisky will be diminished and will eventually stop altogether. No two casks will react the same way and the quality of the cask is key to making great whisky. So careful cask management is essential.European oak casks in the great majority of cases have previously been used for sherry and some Scottish whisky companies such as Edrington actually own bodegas in Spain to provide ideal casks for their whisky.Sherry casks tend to be toasted rather than charred.The issue of moving whisky out of one cask and finishing it in another will be dealt with in a future issue.Did you know… Jack Daniel’s is often mistakenly described as a bourbon but it’s not.It fails to be one on a technicality.America’s most successful whiskey is filtered through specially-prepared Maplewood to make it smoother, thereby contravening bourbon production laws.The reason is that Jack Daniel’s is dripped through charcoal when it is ‘white dog’, or new make spirit. The charcoal reacts with the raw spirit and changes it before the wood gets to work. With ‘charcoal filtered’ bourbon the whiskey is passed through charcoal when it has already been transformed in the cask and just before it is bottled.GLOSSARY Caramel
Caramel is sometimes added to whisky to provide a consistency of colour from one batch to another. It’s not meant to impart any flavour to the whisky but experts will tell you otherwise.Cask strength whisky
Whisky that is bottled at the strength it comes out of the cask as opposed to the 40% to 46% strength that the majority of whiskies are bottled at once the stronger whisky has been mixed with water.Chill filtration
The production of whisky creates a number of oils and fats and these make the whisky look cloudy when it is cold. But they can be removed by chilling the whisky and filtering them out with cardboard filters. Recently there has been a trend away from chill filtering because it is believed the impurities contribute to the whisky’s overall taste.Cleric
Whiskymakers’ name for new make spirit.Condensers
The piece of equipment that turns the spirit back to liquid. Normally copper pipes surrounded by cold water.Congeners
The name of the organic chemicals present in the liquid that results from distillation. Hundreds exist and many have to be separated from the final whisky because they are poisonous, taste horrible, or both.Continuous distillation
Single malt whisky is made in batches. But grain spirit can be made in a continuous still, thereby allowing for much greater quantities.The spirit is stronger than single malt spirit and not as tasty. Through this process we get vodka, the base spirit for gin, and the grain whisky used in blends. The process was invented by Scotsman Robert Stein but was perfected by Aeneas Coffey, an Irishman.Copper
Copper is used because it reacts with the distilled spirit and removed sulphury and vegetal aromas and other impurities. The more a whisky meets copper in distillation, the longer the ‘conversation’ it will have. Big tall stills produce light whisky, and small squat ones a thicker, more oily spirit.