The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

Oven problems

Lloyd28's picture

Oven problems


I have just made a earth oven following kiko denzer's book but altough I can fire it up successfully

I cant get it to retain the heat for very long.I used earth and vermiculite in the insulation layer but the outside plaster coat

does get quite warm after a half hour fire.

Have i got to put thicker insulation layer? I can cook everything else except bread properly

Any suggestions greatfully received


ClimbHi's picture

I know very little about Denzer ovens specifically, but what you describe points to the possibility of insufficient thermal mass. More, or better, insulation won't do anything to help the oven bake if there's not enough mass in the oven walls & floor to soak up and store the heat. How thick are your walls under the insulation layer? Are the walls as thick as Denser specifies and made of the specified materials? That's the first place I'd look.

But if the mass is OK, then more insulation may indeed be the answer.

Pittsburgh, PA

Faith in Virginia's picture
Faith in Virginia

I would be very interested in the specifications that your using and the % of mixes your using(earth to vermiculite) That would help to determine what the problem is.  I am currently building my oven so if there is anything I need to change in my plan now is the time to know. 

My oven is firebrick with 7.5 inches thermal mass in the floor and 7 inches in the dome. I'm also using all fire brick and refactory cement.

My next oven will be an earthen oven.  It will be interesting to compair price and ease of building the two different ovens.  I have a chunk of change in my current oven

pdiff's picture

How long are you firing.  In my brick Pompeii dome, I have to fire at least 1-2 hours on a cold oven to get good heat soak and bake bread.  Someone here also posted about pulse firing, where you light successive fires in the oven over the course of a day or more.  I was skeptical about how well that would work, but after trying it, it definitely makes my oven stay very hot for a long time.  After only a couple of fires in a day, it will easily hold 400+ F overnight with the door on.

dominique's picture

Bonjour !

Half an hour is not enough to obtain a long during warm. It is enough if you just make pizzas. But in order to make bread, it needs to fire the walls of your brickoven two hours.

varda's picture

I wasn't quite sure if you meant you are firing it for only a half hour or not.   I also made a denzer oven.   I put glass bottles and a slip and perlite mix as insulation under the hearth.   I fire it up for at least 1.5 hours - usually 2 before I bake.   But the difference between a successful bake and not was getting a thermometer.  I use a cheap wood stove thermometer that I just lay on the oven floor (a bit to the side to stay out of the way of the fire.)   Then I build up the fire until the temperature goes up to over 600degF.   That's when I call it ready, since I know I will lose some heat when I remove the wood and coals to bake.   I have a thick plywood door to cover the opening which also seems to help retain heat before and during baking.    I never insulated the dome which is at least 4 inches thick, but it seems to retain heat for several hours - I haven't tried baking sequentially, but if I put a dutch oven in with a stew after baking bread, it cooks just fine.  Do you have a picture of your oven?