Most brewers love to recreate the old styles, but even the most dedicated and traditional struggle with Scotch ale. Problems with duplicating the old style arise in nearly every aspect of brewing. It begins with the malt. In Scotland it was peat, certainly it must have infused a smoky character into the beer. Hard to tell, and harder to measure.
Problems continue past that obstacle.
No records remain of the type of malt, its color, the variety of hops, or size of the brew. Worse yet, prior to the 18th century thermometers were absent from the brewhouse. Lack of temperature records leaves brewers with nothing but speculation on the mash and fermentation temperatures. Knowledge of Scotch Ale that remained was gathered in bits and pieces. Generally it was defined by designators originally tied to the amount of malt used, and labeled by the amount of tax paid in shillings.