In a large Dutch oven over medium-high heat, heat the olive oil. Season the short ribs with salt and pepper, to taste, and sear in the Dutch oven until brown, about 5 minutes per side. Remove the meat from pan and set aside. Add the onions and garlic to the same pan and saute, until lightly browned. Scrape any brown bits from the bottom of the pan using a wooden spoon. Add the carrots and celery and let cook for 5 more minutes.
Add 1 cup of beef stock and scrape bottom of pan to remove any more browned bits. Return the meat to the pot along with the remaining stock and the beer. Season with salt and pepper, to taste. Bring the stew to a simmer and cook uncovered for 20 minutes. Cover and braise in the oven for 2 hours.
Serve with a fresh green salad or on top of mashed potatoes, if desired.