The Fresh Loaf

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Does steam affect the oven thermostat? I'm losing heat.

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Simon280586's picture

Does steam affect the oven thermostat? I'm losing heat.

I've been having trouble keeping my oven at the desired temperature when baking bread.

We've moved house recently and I'm still trying to adapt to the new oven. It has coils at the top and bottom, as well as a fan. I've got two baking stones in there (above and below the bread), as well as a cast iron pan at the bottom for steam. I tend to give the oven a good preheat with the fan running, about an hour, until it gets to about 260c. Then switch the fan off, load the bread and pour boiling water in the pan. I use both top and bottom coils ('conventional heat') as the bottom coil alone never seems to get the oven hot enough. I have an oven thermometer inside the oven which seems to be accurate (it matches the preheating temperature).

However, from the moment I close the oven door, the temperature steadily drops down to about 200c within the first 10 minutes or so. The oven's 'heating' light doesn't cycle on during this time, unless I raise the dial higher than the temperature I want.

So I was wondering whether steaming the oven has the potential to affect the oven thermostat, or whether the problem lies elsewhere? Any thoughts appreciated.

mrfrost's picture

Seems this would be easy to test by taking these same measurements while not using steam. Everything else would remain the same, of course.

Also, I typically load my bread when I know the temp cycle is on an upswing(just after the thermostat light turns on). As opposed to just after it has turned off. Especially if I am trying to make steam.

Xenophon's picture

the difference but  first heating and then vaporising the water itself takes a lot of energy out of the system and moist air conducts heat more efficiently than dry air so it stands to reason that your overall energy loss will probably be larger.  And most home  oven thermostats tend to overshoot their intended temperature in both directions, it's done intentionally to some extent to reduce 'cycling'.   Usually the top temperature rating is also exaggerated, same as what's painted on the speedometer of your car vs what the engine actually can produce.  I've got the same problem with my (so called semi-professional) oven that I use for bread/pastry baking.  The only solution is to get to know your oven and compensate for this + use a good oven thermometer.  But you have to compensate temps/baking times anyway depending on how large the loaf is etc.  

For the temperature issue you need to have an over dimensioned oven (huge heating capacity + massive buffers to store the heat and an electronically monitored thermostat).  That's what they use in commerce but those beasts cost a lot of money, are huge/heavy and unless you own a power plant will turn out to be quite expensive in terms of electricity consumed.  I also own a smaller microwave/conventional system that goes to 300 centigrade (actual temperature) and is electronically monitored to maintain a constant temperature but it was very pricy and only allows the baking of one loaf at a time so in practice I only use it for small pastry items.

mrfrost's picture

I will add that doing as I described above, the thermostat stays on for only about 3 minutes, even though the oven is full of steam(oven window fogged up).

I think you are going to find your oven is doing essentially what it always does, steam or no. Try letting the thermostat cycle off, then waiting for it to cycle on again. Load bread and make steam immediately after the thermostat has cycled on again.

ps: If you have a fancy oven with electronic controls and all, do this at your own risk. It may make so much steam as to short circuit the electronic controls.