Single Malt - A product of a single distillery that is not mixed with whisky from any other distillery.
Single Grain - The product of one grain distillery and is usually made from corn, wheat, or unmalted barley.
Blended Malt - Will contain a number of malt whiskies that have been skillfully married to create a consistent whisky with character.
Blended Grain - Blended Grain Scotch Whisky means a blend of 2 or more Single Grain Scotch Whiskies from different distilleries.
Blended - Blended Scotch Whiskey may contain a combination of whiskies from over 40 -50 different malt and grain distilleries. The normal ratio of malt to grain is 60% grain to 40% malt. The percentage of malt used will determine the quality and smoothness of taste and character. Each whisky used in the blending process will normally have been matured for about 5 years.
Lowland Scotches typically have a dry finish, which makes them excellent aperitifs. The dryness comes from the malt itself, not from peat, as lowlands tends to use unpeated malt. This also lends a certain sweet fruitiness to the flavor and texture. Their aromatic intensity is low, and tends to be grassy or herbal, with grainy and floral notes.
The highlands are sub-divided into different regions, and they each have different flavor profiles. In general, these whiskies are much less peated than there southern cousins in Islay, but they all tend to showsmokey notes. Their uniting flavors are a sweet start and a dryish, peppery finish.
Speysides are essentially sweet whiskies. They have little peaty character, although some have a whiff of smoke. Their Salient characteristic is estery - typically compared to solvent (think nail varnish remover). They also can be highly perfumed, with aromas of roses, violets, apples, bananas, cream soda and lemonade.
Talisker is the only distillery on the Isle of Skye and has a flavor profile all its own. The character of the malt is sweet, the whiskey is peaty and full bodied.
Islay whiskies are the antithesis of the Speyside whiskies. They are dry, peaty and the strongest flavored whiskies of Scotland. The distilleries in the south of the Island and the most powerful (Ardbeg, Lagavulin, and Laphroaig) are saturated with peat, brine and iodine. In the North of the island distilleries like Bunnahabhain, produce more refined, less peated and more delicate whiskies that show a refined seaweed and nuttyness.