Heat crock pot and add Guinness, stock and carrots.

Put beef pieces, salt and pepper in a freezer bag with flour. Shake.

Heat fry pan with oil and add entire contents of freezer bag.

Brown meat, add onion and celery.

Add browned beef and contents of fry pan, including flour, to crock pot.

Cook on high for 4 hours or low for 6 or more hours.