The Fresh Loaf

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Anyone have data on heat transfer rate...

tlmcca's picture
tlmcca

Anyone have data on heat transfer rate...

Anyone have data on heat transfer rate to a cast iron dutch oven during preheat?

I just did my first bake in my new Lodge 5 quart DO (pictures to come) and I'm wondering whether a full hour preheat at 500 degrees F is necessary. I don't have an infrared thermometer so I don't know how long it took for the DO to reach the target temp nor where it really topped out. 

If no one has the data I'll invest in an IR thermometer and run the numbers and share here.

Thanks,

Terry

idaveindy's picture
idaveindy

It depends on too many things.  Such as, the size of your oven, the number and size of the heating elements, whether your oven uses the top broiler element during pre-heat, how far the vessels are from the heating elements, whether a convection fan is in use, whether you block direct radiation via a baking stone or cookie sheet, etc.

Direct radiation plays a big part, and that varies according to the square of the distance from the heat source to the object.  (Like how the sun on your  skin feels hotter than air temp. Or how a car gets hotter than the air temp on a sunny day.)

That Lodge 5 qt combo dutch oven is pretty heavy, so it probably does take 45 min to an hour.  Keeping the pot and lid separate during pre heat exposes more surface area to the hot air, and to the direct radiation of the heating element(s), and will therefore pre-heat faster.

i recommend getting the IR thermo gun.  If it saves you 15 minutes of pre-heat, it could pay for itself in time, and maybe eventually in electricity.   

and it will let you know exactly how much actual temp is off from the oven setting, if any. 

DanAyo's picture
DanAyo

Terry, the following link wasn’t specifically focused to your specific question, but you may find some of the data useful. http://www.thefreshloaf.com/node/56822/cast-iron-cooker-vs-graniteware-thermal-data

Notice the time it took for the CI to come up to temp. I estimate the start of the preheat was ~9:15 in the thermal chart.

The vessel should be placed back in the oven ASAP. Both the graniteware and the CI lose heat very fast. The CI takes longer to recover, but also loses heat slower.

An IR gun is a good investment. It is good for oven and vessel temp, but also for reading the dough temp (accurately) during fermentation. Great for BBQ!

Dan

barryvabeach's picture
barryvabeach

Terry,  Dan is the expert on most of these things, so maybe he knows, but I often wonder why it would be necessary to preheat the entire DO. It may make sense to preheat the bottom, on the theory that heat from the bottom will help oven spring, but I have trouble understanding why you would want more heat from the top or sides, since that would cause the crust to harden and decrease oven spring.  I have a combo cooker ,  and I put the flat part on a gas burner, and get get it up to 400 degrees in a few minutes  ( confirmed with an IR gun ) and then put the top on and throw it in the oven.  Not only is this much quicker than the long preheat times in the oven, there is less danger of burning your hands because the top is at room temp. 

BobBoule's picture
BobBoule

Cast iron heats up surprisingly fats but that way I look at it is that I have to heat up my oven as well, so we are accomplishing two things at the same time.

I do have a non-contact thermometer and my dutch oven is up to temperature in 30 minutes. Everyone's oven is different so I suggest tat you get an inexpensive non-contact thermometer (they are very low priced now and can be used for many different things) to see how long you dutch oven and how long your oven take to get up to temperature.

I do take the lid off and lay to by the side of the dutch oven, because if I leave the lid on then it seemed to need 45 minutes to heat up.

This i stew thermometer I purchase from Amazon: https://amzn.to/33PWuOi