Line a cookie sheet with wax paper; set aside.
In a heavy bottomed saucepan, over medium heat, melt butter and brown sugar. Slowly add beer, syrup then milk, stirring constantly.
Cook caramels to 240°F; continue stirring without stopping. Once 240°F is reached, remove pan from heat and stir in vanilla.
Pour mixture into 9x13 pan lined with parchment paper; working quickly, line half of the poured caramel with one layer of the pretzels; quickly fold the unlined half over the half lined with pretzels;
Sprinkle sea salt on top of hot caramels; let caramels set until firm enough to cut. (Hint: if the knife is pulling the caramels, spray a light coat of cooking spray on each side of the blade)