Irish Guinness Stew

I wanted to make some pub-style Irish stew to celebrate St. Patty's Day.
This recipe is done in the slow cooker/crock pot.

Ingredients

2 1/2 Pound stewing beef, cut into 2-inch cubes
1/4 Cup all purpose flour
1 Teaspoon salt
1 Teaspoon fresh cracked black pepper
3 tbsp. olive oil
1 cup 1/4-inch diced onion
3 carrots, peeled and chopped into 1-inch pieces
3 red potatoes, cut into 1-inch pieces
3 stalks of celery, cut into 1 inch pieces
2 clove garlic, sliced
1&1/2 Cup beef stock
1&1/2 Cup Guinness or other dark beer (an entire bottle/can - approx. 355ml will do)
2 tbsp. tomato paste
1 tbsp. Worcestershire sauce
2 tsp. thyme leaves, chopped (1/2 tsp. dried)

1. Coat the stewing beef in 1 tbsp. flour, salt and pepper. Brown in frying pan with olive oil. Do not cook all the way through, just enough to brown the outside.
2. Add beef to slow cooker. Add all of the brown bits from frying pan as well, it adds flavour. Add leftover flour. Stir well.
3. Add remaining ingredients in the order they are listed and stir mixture.
4. Set slow cooker on low for 6-8 hours.