Potato Cheddar And Ale Soup

• 1 1/2 scottish ale
• 1,800 gr russet potatoes
• 2,800 ml chicken stock
• 700 ml milk
• 375 gr carrots
• 325 gr cheddar cheese
• 300 gr celery
• 80 gr butter
• 24 gr flour
• 3 gr fennel seed