1. It’s all simple math: 1 slice of bread is 66 Calories: Calories in White Bread and Nutrition Facts
2. 462 Cal. Is 7 slices of bread.

3. 1 ounce of beer = 15 Calories: Calories in Oktoberfest Beer - Calorie, Fat, Carb, Fiber, & Protein Info

4. 30.8 oz. of beer = 462 Calories.

5. Therefore 7 slices of white bread = 30.8 oz. of beer
Amazon.com | Personalized 32 Oz. (One Liter) Monster Beer Mug - Engraved/Etched Giant Glassware: Personalized Beer Stein: Beer Mugs & Steins

Cheers!
PS. Don't fill that beer mug all the way to the top, keep it 1 inch from the rim and you will be bang on.