Hamburgers, Scandinavian Style

• 8 rye buns
• 8 from coals (inches)
• 1 loaf rye bread
• 900 gr beef (ground)
• 120 ml wine vinegar (red)
• 60 ml catsup
• 60 ml salad oil
• 6 gr instant onion (minced)
• 6 gr salt
• 3 gr pepper