Adding Hearth Insulation

[Xabia Jim]

If memory serves me well, insulation is better than thermal mass, particularly for the pizza oven. I think it's good to have some thermal mass to hold heat, particularly for the baker. But certainly it seems you can have too much mass to heat up and thus the insulation layers. A careful balancing act.

Francis, are you talking about putting bricks on top of your hearth? You could probably do a test by just loose fitting in as many bricks as possible then. I've got to believe that heating up another layer of bricks will increase your thermal mass for baking. And how long does the fire burn to season your oven before baking?

6" of vermiculite under the dome... it seems you can't have too much insulation....how much would be too much?

[Frances]

Too much? I dunno, so the oven is too high to cook in maybe Like the princess and the pea, you'd have to use a ladder to get up to the entrance...

I think I've got about 6" of vermiculite under the dome, and the roof of the wood storage area doesn't get warm, or if so only slightly.

Baking for me is usually after making Pizzas, so heat up time (including the pizza bake) is around two hours, close the door, and put in the bread another two hours later - give of take an hour or so, and depending on when the dough has risen. Its never a very exact science for me, I'm afraid...

And as I say, its working very well, we have lots of fresh bread that everyone in the family likes to eat (and thats a seven day wonder all in itself!)

Bit I think I'll try putting some bricks on the floor sometime to see what happens. I'll let you know what happens. Afterall I can always take them out again...

[Xabia Jim]

You could just use high heels princess.

[gjbingham]

George reporting: I cooked pizza's (poorly) tonight. Ambient temperature was around 60 degrees. I checked the underside of the slab's temp: 62 degrees F. Outside the stucco: 59 degrees. Conclusion: Four inches of vermiculite is or may be enough, or at least the heat the heat from the oven is not making it all the way to the bottom of the slab enough to pursue insulation underneath.

On the down side, I stoked the fire big time tonight and put a crack right through the top of my decorative arch. I hardly gave it a second thought.

[Frances]

Hey, watch out or we'll get to where we brag about the size of our cracks...

"Mine's bigger than yours!"

[Xabia Jim]

No, in the crack business we brag about mine being smaller than yours!

[gjbingham]

Hey, no cracking jokes!

[Xabia Jim]

Interesting, where did the term "cracking a joke" come from.....

[Xabia Jim]

Crack (craic) - Wikipedia, the free encyclopedia

don't ya just love google, wickipedia and the internet?

[Xabia Jim]

Crack or craic is "fun, enjoyment, abandonment, or lighthearted mischief; often in the context of drinking or music".

and with that thought we should all be proud of our cracks, particularly in the context of wood fired ovens, drinking and music!

talk about fun and lighthearted mischief,
what a group!!