Place roast in crockpot.
Place potatoes, carrots & onion around the roast.
Pour in the beef stock.
Time to pour that beer!
Sprinkle in salt, pepper & garlic and cook on low for 8hrs.
After roast is fully cooked, take 2 cups of liquid from the crockpot and pour it into a sauce pan.
Whisk in the water and cornstarch in with the roast juice to make a gravy.
Bring to a boil, stirring frequently for 3-5 minutes until it begins to thicken. It will thicken as it cools as well.
Drizzle the gravy over the roast, carrots and potatoes and enjoy!