Preheat to 300 degrees.
Place beef bones in a large bowl and dust with corn starch. Roll or toss the bones in the bowl to make sure they are well coated.
Place the bones in a single layer on a cookie sheet or roasting pan and drizzle with vegetable or canola oil. Roast for 30 minutes until slightly browned.
Add onion, celery, carrots, and garlic to the pan and spread evenly around the bones. Bake for about 30 minutes until bones have a deep golden brown colour and the veggies are absorbing some of the beef juices.
Once roasted remove pan from oven and place on stovetop. Drizzle with about half of the red wine and toss to evenly coat and loosen up the brown bits. Transfer all the ingredients including all the brown bits on the pan into a very large stockpot. You may need to scrape the pan a bit to do so.
Add all ingredients to the stockpot and splash with remaining wine. Bring up a medium heat and give the ingredients a bit of a stir to distribute the juices and wine until somewhat reduced.
Next, fill the pot with water to generously cover the meat bones. Add the bay leaves, peppercorns, and thyme. Bring the mixture to boil and then reduce to simmer for at least 8 or more hours. You can simmer up to 24 hours if you like for fuller richer flavours.
Once it is done simmering you will need to remove the bones and vegetables and strain the stock into another stockpot. Let mixture cool down until just warm. Place a metal strainer over new stockpot and drain ingredients. Discard bone and vegetables.
At this point, transfer the pot to the refreigerator and leave in overnight. Once completely cooled it will form a layer of fat that can be removed and discarded.
Return the strained liquid - minus the fat - to the stove and simmer for about 30 minutes until the mixture has just slightly reduced.
Remove the pot from heat and let cool until warm. The stock can then be transferred to the desired containers and used immediately. Stock can be stored in the fridge for about 5 days or in the freezer for up to 6 months.