The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

Mud oven losing heat through base layer

Arcticteach's picture

Mud oven losing heat through base layer

I am having problems with a new oven we build here at The American school of Kinshasa here in the Democratic Republic of the Congo. This is my third mud oven ( a la Kiko Denzer's book) and the other two work great! (both in Colombia) Fifth firing yesterday and it looses heat rapidly. I can see that the materials have all dried from the oven floor up, but there is still a clear line of not fully dried material below the oven floor (insulating mud with wine bottles) Seems like the bottom is taking an inordinate amount of time to dry. My guess is that the still damp materials below the oven floor are robbing the heat from the bricks and oven as soon as I pull the fire out. Does anyone have any hints or tips on drying this out? My plan is to fire the oven a couple of times a week. My wife says that I am not being patient enough.

OldWoodenSpoon's picture

but it seems like your plan is the only reasonable one, your wife being right notwithstanding ;)  I have already destroyed one Denzer-style oven dome by over-firing too early.  Now I am waiting for dry weather to rebuild my dome. My base layer was also layed down with wine bottles in mud-and-wood-shavings insulation and took a good long time to dry.  Firing gently will certainly dry it out, and only then will you be able to tell how well it is going to hold heat.  Be patient though, because while it is all still quite wet the water will turn to steam if you overheat it, and then it will expand and damage your oven.

Best of luck with it

Mini Oven's picture
Mini Oven

You could place a fan near or in the oven to get the surface to evaporate sooner or angle a mirror to shine sun onto the floor of the oven. Or both.  Temporarily placing a large pipe into the oven, hung from the top opening and extending toward the back inside of the oven (chimney effect) might improve circulation but the process will take time.  

Wishing you Patience and Congratulations!

Roo's picture

I am with all of the above . . . and your wive on this one.  Patience.  Every oven regardless of type has it's own personality so while the 2 previous ones work great this one is just taking it's own time to get there.

Do you remember how long it took to cure the other 2?  What time of year and what were the weather conditions during the building and curing of the other 2?  Build you curing fires and enjoy this part of the process as well.