Overnight cooking: Is sous-vide safer than electrical oven? I am a fan of bone broths, but always have a problem with the overnight cooking part.

For the overnight cooking part I have the following options:


Interrupt cook, let the pot hot on the stove, continue in the morning (this is what I am doing now)
Cook overnight on the stove (this seems to be a bad idea)
Cook in an oven overnight. Some people say, that this is a lot safer, than the stove, but I am not willing to do it. 
Stand-alone stove on the balcony. I actually believe, that this should be pretty safe. 
My latest idea: Put the bone broth pot in a big container full of water and heat the water with a sous-vide circulator.


Since sous-vide circulators can not reach as high temperatures as an oven and since they are, after all, in a container full of water, is it safe to assume, that overnight sous-vide is safer than overnight oven cooking? I could make it even safer, by putting the whole thing on the balcony, however this would probably increase energy consumption dramatically.
On top of the stove the issue is boiling dry. At that point the temperature can rise almost unchecked. This will result in unpleasant fumes at best, flames at worst. Even in the latter case, because you should be using a fairly tight fitting lid, everything should be contained, but I wouldn't rely on that.

The oven is different. Once the pot is up to boiling point you can set an oven temperature of just over 100&deg;C. In the unlikely event of boiling dry, the contents still won't exceed that temperature - no burning. Like you I assume an electric oven.

Using a sous vide circulator you'll actually struggle to get the inner pot hot enough - you generally want a gentle simmer for broth/stock. The outer pot will loose a lot to evaporation even if it never boils.

I'd have more confidence in the oven, but if you're shopping there's one more option - a slow cooker. Making stock is trivial: put in bones (and any veg etc.); pour over boiling water; leave on high for a few hours or low for up to a couple of days; strain. I normally use low overnight for chicken stock with onion, celery, &amp; herbs. These are specifically designed to run for long periods unattended without boiling dry (as the power input is low and the lid fits tightly).