Though Scotland is more famous for its whisky, its ales have historically been an important and renowned export as well. Scottish ales are known as some of the most malt-focused beers around. Scottish yeasts typically have lower levels of attenuation, which along with the use of good crystal malts results in a sweet, malty beer. The yeast also is able to function at lower temperatures than normal for ale yeast, down to about 55 degrees. Keeping the fermentation temperature low helps keep fruity esters to a minimum, resulting in a cleaner flavor.
As an alternative to using crystal malts, brewers can also employ traditional kettle caramelization techniques. Try performing a 90 or 120 minute boil when making a Scottish Ale, or take a small amount of condensed wort (either by using less water in extract, or by taking the first runnings in all-grain) and boil it down to reduce it. These techniques will provide richer, fuller malt flavors to any Scottish Ale, while still providing a fairly attenuative wort.
60, 70, 80, 90 Shillings -
The Scottish system of rating beers by their cost (and thus their gravity/alcohol) is divided into different shillings. 60 Shillings are low in gravity (sometimes only 1.030), but feature pleasant malty fullness that keep them from being too thin. Though 60 shillings can be found on cask in Scotland, their export is very rare and they are generally not available in the US. A more standard gravity beer, but still quite drinkable, 70 shillings are between 1.035 and 1.040. 80 shillings have a wider range, from about 1.040 to 1.054 starting gravity, and 90 shillings are even more loosely defined, ranging up to fairly high abv% levels.
Wee Heavy -
The Scottish Barley Wine. This style is deeply malty and ages very well. The body is full and thick and the color ranges from coppery red to dark amber. Some homebrewed examples feature small amounts of peated malt for a slightly smokey tinge, or small amounts of roasted barley to add color and complexity. The gravity can range quite a bit and can be astronomically high, up to 1.130 in some cases!