For a Dutch oven, assuming it's enameled:

If it's baked, 375F, 2 hours

If it's roasted 255F 2.5 hours

If it's cooked 185F 3 to 6 hours.

But I never use a recipe, so the above can lead to disasters. :-)

dcarch

Seems to me there should be some way to calculate this. Seems that most food has very roughly similar density and water content - else it wouldn't be edible - and thus should have similar heat conductivity. And most food cooked in an oven has roughly similar shape - I mean, a squat shape that fits in a pot - thin flat things like pizza are a rarity. Thus at a given oven temperature Y, we should be able to say that it will take roughly X hours to heat the center of the food to a given temperature. I'd guess that 180 F is an internal temperature that could work for most oven-cooked food. Then all you have to know is if your dish is meant to cook for a long time (the raw food is tough and needs to be broken down) or only needs to reach that temperature for a little while (the raw food is already fairly malleable), and if there is a surface browning effect desired (that you would judge by eye).

Dcarch, is that how you derived your rule of thumb?

Variables not being considered:
Big difference in conductivity between bone and meat.
Connective tissue needs time to gelatinize.

Depends on what's in the dutch oven - a stew? a roast? chicken? beef? pork? bread? covered? uncovered?

My "usual" is 350 degrees for at least an hour, or until it's done or tender or whatever your goal is.

The nice thing with a dutch oven is that you can take the top off and check the food.

This is only applicable to chicken, but Julia Child's formula for poulet en cocotte (casserole-roasted chicken) in a 350 degree oven was 7 minutes per pound, plus 45. So a 6 pound bird would take 42 + 45 minutes, or about an hour and a half. This is assuming the casserole or dutch oven was hot when it was placed in the oven.

In my family it's a joke that 350F is the "universal temperature", the one you use if you just don't know what temperature to use.

However, I also agree that it depends on what's going into the pot. If it's a brisket or chuck roast, then it's 300F for 3 or 4 hours, or until tender. If I'm roasting chicken, then I leave the top off and crank the heat up to 400F for the crisp skin that everyone else wants. Lasagna or other pasta dish? 350F until it's done and hot through. Cake gets 350F, bread gets 400F.

I have no apparent rule of thumb, I seem to just do as I please and it works most of the time.

Annie

Snow day and storm prep anxiety, i cooked all day last tuesday...
One meal event was a beef stew. Not using a recipe, just instinct, in the oven by noon,
i decided on 220 for 4-5 hours. It was in and out a couple times. Once for some crackers that needed baking and later for a tray of roasted veg. It ended up right where i wanted it.
My X and Y determined on table serving time being aprox 7pm. Giving it a rest again around 5 for a while as i believe a stew needs a rest, then back up to high heat just before serving.
This was not a crock-pot deal. I had the time to give it attention.
I do think a rule of thumb comes into play, using density and experience. This beef, cut large, spent the first hour alone with just a large onion. And a bit of Guinness. Added the softened vegetables, also cut large, after an hour, with a pint of smoked stock, a few chopped tomatoes. Enameled cast iron was just over half full.
A crock-pot deal-e-o can be good and comforting. Having the luxury to babysit and give some care about time and temp can elevate to fantastic.