Black-Briar Reserve is a food in Skyrim. Consume it to restore stamina, but get a penalty to your stamina regen.
Effect: Restore 30 points of Stamina. Stamina regenerates 40% slower for 30 seconds
In NPC's Inventory
Can be found in Black-Briar Meadery
There is a weaker version of this drink, the Black-Briar Mead