I can see adding tomato paste to a soup I make with the stock, I am not sure I would want to use it while making the stock itself. Can't imagine it wouldn't be right tasty though.
I probably should not be posting here as I am new to the cooking experience. However, my limited exposure has convinced me that making a good stock (as well as roux) is a valuable fundamental to master.
Here is what I consider a great how to article for making beef stock
Brown Beef Stock – The Culinary School Recipe | Island Vittles
It mirrors what many of you have already said...Roasting the bones with a mirepoix. Brushing with tomato paste then roasting some more. Other points I picked up on was that is is important to use COLD water as the first liquid to help extract the good stuff from the roasted bones. So far I have added a bouquet garni for seasoning the stock. I have also read to avoid stirring a stock as it will cloud it.
For me though, the simple but important issue of determining whether my stock (etc.) has achieved a state of low and slow simmer or boil is in question. Simmer is good. Boil is less so. I have tried measuring with a thermometer which works ok. But whenever I see other cooking programs that says 'Simmer', there seems to be more activity in their pot than what happens in mine. I have read that simmer is below a boil so, at sea level at least, the temp should be in the 190 to 205 range. But that range just doesn't 'look like' what others consider simmer.
How do you determine simmer / boil state, or is it too trivial to even consider?
Thanks