Moonshine is the strongest alcohol in the game. Though it has the same 10% addiction rate as lesser alcohol, like whiskey, it bears doubled SPECIAL bonuses and penalties with a bonus of 2 to Strength and Charisma and reduction of two points of Intelligence. Mentats can be used to negate the Intelligence penalty.
Beer might be a preferable alternative, considering its 5% addiction rate and the copious amounts of it, scattered throughout the Capital Wasteland, but the effects of beer, as with other alcohol, will not stack. This means drinking two beers will not change your stats any more than one would. Moonshine can still be consumed and its effects will "overwrite" the effects of other alcohol. However, beer has a value of only 2, but moonshine has a value of 50; moonshine may be better suited to selling, rather than drinking.
Moonshine is a common term for home-distilled alcohol, especially in places where this practice is illegal. The name stems from the American Prohibition era, where homemade stills were often operated under the light of the moon.