Mum's the Word
The Prodigal Brewing Company

Though they may not be a glamorous grain, oats have been utilized alongside barley, wheat, et al. for as long as there has been agriculture and there has been beer. In the hardly kind words of Dr. Johnson's 1755 dictionary, oats are 'a grain, which in England is generally given to horses but in Scotland supports the people.' Yet in spite of his uncharitable characterization, oats are a natural accompaniment in many a fermented draught. That they impart a creamier, fuller and softer mouthfeel almost reminiscent of rich raw milk makes it a natural pairing for the stout. The coffee, chocolate, and sundry flavors that are common therein may be upheld by an enrichening backbone of oats, and thus the dubbed Oatmeal Stout came into being.
Though the grain had been utilized for hundreds of years in brewing, particularly in the northern reaches of Albion, the term 'oatmeal stout' truly was bestowed in the late nineteenth-century, where advertisements began to appear touting its healthful properties. All things being as they are regarding the healthsomeness of beer, oats do impart their due portion - their relatively high protein content does merit a measure of notice. A pint of such a stout may be made a meal in itself. The drinking classes of yore, yoked with their troublesome work, began many a tiresome day in such a manner. But let us not proscribe the past onto today's manners.
Mum's The Word is in definition a very simple stout: following an age old method that I shall not be divulging further, for, as it were, 'mum's the word.' What you can take to heart is that it is a light, drinkable stout that hits all the hallmarks of its style while not skipping in the quality of oats. The Irish and the Scots do have something on their English cousins, their oats are of much finer quality; absolutely wasted on horses.