Law & Production Process

Single Malt Scotch Whisky

Made at a single distillery, from 100% malted barley, distilled exclusively in pot stills. "Single" refers to the distillery, not a single cask. Age statements reflect the youngest whisky in the vatting.

Single Grain Scotch Whisky

Made at a single distillery. May use grains other than malted barley (typically maize or wheat). Usually distilled in a Coffey (continuous) still. Lighter and cleaner in style; primarily used as a blending base.

Blended Malt Scotch Whisky

A blend of single malts from two or more distilleries. Formerly called "vatted malt." The term "Pure Malt" is effectively prohibited under EU regulations.

Blended Grain Scotch Whisky

A blend of single grains from two or more distilleries. Rare as a commercial category.

Blended Scotch Whisky

A blend of one or more single malts with one or more single grains. Accounts for roughly 90% of all Scotch exports. Examples: Johnnie Walker, Ballantine's, Chivas Regal, Dewar's. Grain content typically 60–80%.

Raw Materials (Barley & Water)

Raw Materials

Two-row barley is standard for single malt — higher starch content than six-row makes it better suited to malting. Modern varieties (Concerto, RGT Planet, etc.) dominate. Islay's water passes through peat before reaching the distillery, picking up minerals and colour that influence fermentation and flavour.

Malting

Malting

Barley is steeped in water (2–3 days), then spread to germinate (5–7 days), activating the starch-converting enzymes (amylase). Traditional floor malting — spreading barley on stone floors and turning it by hand — survives at only ~10–12 Scottish distilleries. On Islay: Bowmore, Laphroaig and Kilchoman.

Kilning — This is where the peat character comes from

Kilning

Germination is halted by drying the malt in a kiln. Burning peat during this stage releases phenolic compounds that adhere to the malt, producing Islay's signature smokiness. The time and quantity of peat burned determines the phenol level (ppm). The distinctive pagoda roof on traditional kiln buildings was designed by architect Charles Doig in 1889.

Mashing

Mashing

The dried malt is milled into grist and mixed with hot water (65–68°C) in the mash tun. Enzymes break down starch into fermentable sugars, producing a sweet liquid called wort. The spent solids (draff) are typically used as animal feed.

Fermentation

Fermentation

Wort is transferred to washbacks and yeast is added. At 25–32°C over 48–110 hours, the yeast converts sugar to alcohol, producing a beer-like liquid called wash (~7–9% ABV). Wooden washbacks allow bacteria to contribute flavour complexity. Fermentation is said to determine 60–70% of the final whisky's character.

Distillation

Distillation

Copper pot stills are used for two distillations (typically). The first (wash still) produces low wines (~20–25% ABV). The second (spirit still) separates the run into foreshots (discarded), hearts (the desirable 60–70% ABV fraction) and feints (recycled). The exact cut point is the distiller's art — it defines each distillery's character. Taller stills produce lighter spirit; shorter stills produce heavier, more complex spirit.

Maturation

Maturation

By law, minimum 3 years in oak casks (max 700L) in Scotland. Key cask types: ex-bourbon barrels (~200L) impart vanilla and honey notes; sherry butts (~480–500L) give dried fruit and chocolate. Islay's cool, damp climate means an angel's share of only ~1–2% per year. There are three main warehousing styles. Traditional dunnage warehouses (stone walls, earth floors, casks stacked max 3 high on wooden runners) provide the most stable conditions for slow, complex maturation. Racked warehouses use steel racks to stack casks up to ~12 high — far more space-efficient but with greater temperature variation between top and bottom rows. Palletised warehouses store casks on pallets managed by forklift, the most efficient method, widely used by large-scale operations and for blended whisky production. Most distilleries use a combination of all three.

Vatting & Bottling

Vatting & Bottling

Multiple casks are married (vatted) and diluted with water to the target ABV, typically 40–46%. Cask strength (CS) expressions are bottled without dilution (50–65%). Chill-filtration prevents haze at low temperatures, though many distilleries now offer non-chill filtered (NCF) versions to preserve flavour compounds. Caramel colouring (E150a) is permitted but increasingly labelled.