Melody's Famous Beer Cheese

INGREDIENTS

• 1 (1 pound) loaf rye bread
• 1 tablespoon butter
• 2 pounds processed cheese food, cubed
• 1 (8 ounce) package cream cheese, softened
• 3 tablespoons prepared horseradish
• 1 tablespoon prepared yellow mustard
• 1 tablespoon garlic salt, or to taste
• 1/2 (12 ounce) can beer, room temperature