Cook the bacon until it’s crispy. Remove the bacon and most of the fat from the pan. Rub the roast chunks with salt and pepper. Sear the meat in a little bacon grease on all sides. You may need to work in small batches. Place the seared meat in a crockpot.
Between each batch of searing, clean out the pan with grape juice. Pour the juice into the crockpot over the meat. Add more bacon grease to the pan each time you sear a new batch of meat.
Sauté the onions until they are brown. Add the carrots and celery, cooking for a few minutes. Place everything into the crockpot along with the rest of the ingredients, except for the mushrooms.
Add the mushrooms to the crockpot five minutes before serving. Cook on low for 6 to 8 hours. Serve the Bouff Bourguignon over mashed potatoes, pasta, or crusty bread.