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-   -   Oven hearth does not get hot (http://www.fornobravo.com/forum/f16/oven-hearth-does-not-get-hot-19872.html)

Rolaed 09-02-2013 06:55 AM

Oven hearth does not get hot
 
Three years after building my brick oven, my hearth does not get into the 750degF range. Temps are typically in 500-600 degF range. As a result, pizzas cook really well on top and sides, but bottom is not crispy and does not cook well. I end up using a peel with holes in and place peel on top of fire to make the bottom somewhat crispy.

Any tricks to make the hearth hotter? I followed design rules for insulation from this forum when building the oven.

Should I keep pizza away from the fire when unloading it to allow bottom to cure? any advice on cooking pizza or making hearth hotter is appreciated.

mrchipster 09-02-2013 07:23 AM

Re: Oven hearth does not get hot
 
My first question would be is the floor insulated? And with what and how much?

Second is it possible your floor is damp for any water intrusion?

How thick is your floor and of what type of material?

How hot does the dome get and how well insulated is it?

Where is your fire when heating the oven, you may need to charge the floor by building your fire were you will be cooking the pizza and move th fire to the other side just before cooking.

Photos of the oven please.

shuboyje 09-02-2013 08:08 AM

Re: Oven hearth does not get hot
 
what is your enclosure like? If you insulated as you say you did this either means you aren't firing hard enough or more likely you have wet insulataion under your floor.

Rolaed 09-02-2013 01:45 PM

Re: Oven hearth does not get hot
 
3 Attachment(s)
Attached are a few photos. I have 4+ inches of vermiculite all around the oven. Although, yesterday was the first firing this summer. I have been busy travelling and this has been one of the rainiest summers in Michigan. So it is possible water intrusion is the cause.

The dome is very hot. My IR thermometer reads ERROR when I point at dome.

So if my insulation is wet, what is the solution? keep firing the oven?

Tscarborough 09-02-2013 04:01 PM

Re: Oven hearth does not get hot
 
You will probably have to have a hot fire for 4-5 hours to get that much mass to saturation, especially the floor. As much as I respect Alan Scott's memory, his design is not suitable for recreational cooking. It is an industrial design that when fired daily for bread works great. For occasional pizza, especially Neapolitan, not so much.

michelevit 10-04-2013 09:25 AM

Re: Oven hearth does not get hot
 
Thats quite a bit of mass to heat up. The floor looks like it uses bricks laid on its side. Its going to take forever to heat up, but once it does it will hold heat much longer.

For residential pies its overkill. Like driving an 18 wheeler to deliver pizzas. You really want a geo metro or vespa scooter.

the good news is now you have a perfect excuse to build a thin wall, thin floor pizza oven.

Polo 10-04-2013 10:40 AM

Re: Oven hearth does not get hot
 
Quote:

Originally Posted by Rolaed (Post 160881)
Attached are a few photos. I have 4+ inches of vermiculite all around the oven. Although, yesterday was the first firing this summer. I have been busy travelling and this has been one of the rainiest summers in Michigan. So it is possible water intrusion is the cause.

The dome is very hot. My IR thermometer reads ERROR when I point at dome.

So if my insulation is wet, what is the solution? keep firing the oven?

I would have to say that your problem is surely moisture. I'm assuming that your oven performed better at a point prior to this. There would be no other reason for your hearth to remain so cold. At least none that I could think of.

Yes, keep firing your oven, it should improve.

By your pictures I am assuming that your hearth bricks are laid on your vermicrete insulation. My oven is virtually identical to yours except for the fact that my bricks are laid on top of the hearth support layer. My vermicrete insulation is under the hearth support. If I fire my oven sufficiently to cook four or five pizzas in succession without recharging the hearth, it will take about 3 hours. If I wanted to fully saturate the oven it would take significantly longer.

Tscarborough is absolutely correct. This is not an oven designed to fire up once in a while for a pizza or two. I saturate my over to bread baking temperatures once a week (Saturday evening to Sunday morning). Sunday morning I typically bake 48 lbs of bread.

If I make pizza, I fire it further after bread baking, when the oven is already saturated to 450 F at least 4" into the masonry. I use the residual heat during the following week to do some further cooking. By the following Saturday my oven will still be 110 F. (at summertime temps)

deejayoh 10-04-2013 10:53 AM

Re: Oven hearth does not get hot
 
Looking at the flat roof of your enclosure in the picture - I would venture that it's a combo of wet floor + lots of mass. I can't see all the details, but with a lot of rain a flat roof + exposed masonry is not a recipe for keeping water out. Water could also seep in from the arch area. If you can, pull up a couple floor bricks from the oven and see if it is wet underneath.


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