Saturday, May 28, 2011

Brick Oven FAQ

I demonstrate my portable brick oven at Home and Garden Shows, at community events, and elsewhere.
Here are some of the most common questions that come up:
Q. Is there a fire under the oven?
A. Most brick ovens are heated by fire within the oven. The fire is first built under the throat (chimney) and progressively moved backwards as the fire progresses forcing the flames(and heat) to curl under the dome and leave the BTU's in the brick mass.
Q. How much wood does it take?
A. My 36" oven uses a 'laundry  basket' of dry hardwood to reach 800 degrees. Small amounts of wood are added when continuing to bake pizza and the residual heat can bake other foods for up to 30 hours.
Q. Does this have to be outside?
A. I've found that the ideal place (in a temperate climate) for a brick oven is in a three-season porch. This protects the owners from bugs and weather and extends the season at each end of the year.
Q. How hot is it in there?
A. Way hotter than a household range oven. Usually starting at 700 degrees for pizza and afterwards progressively lower temps for baking bread, roasts, casseroles, and puddings.
Q. Can I build one myself?
A. Yes, with some masonry skills and patience. This blog has featured progressive photos of ovens being built by myself, both portable and stationary.

Sunday, May 22, 2011

Recent Brick Oven Events

It's been a busy spring for both oven building and demonstrating. The sequence of building photos resulted in the portable oven pictured here.

As an addition to past displays at the Northern New England Home, Garden and Flower Show, I collaborated with Maine Turf to create a sitting area and added stone benches from my stock of old split granite. The location provided afternoon shade and a friendly space for people to relax while watching the "Meet the Chefs" demos.

Chefs Jim Davis and Mary Ann Esposito demonstrated brick oven cooking as well as the breads and foccacia which I baked for sampling.

Sunday, May 8, 2011

Brick Oven Dome Building, Part 4

Brick oven domes need insulation in order to retain the heat transferred from the fire to the dome bricks.
This can be high-tech fiber insulation or a composition of vermiculite.  In the case of ovens where the final profile is a dome, vermiculite and Portland cement are combined to form a layer that is both insulating and solid. The mixture is troweled on and shaped, in some cases using forms on the side to increase depth or shape the final oven style.

Note that a tremendous amount of moisture resides in the vermiculite/cement layer and needs to be slowly released when the oven is 'seasoned'.
Alternatively, a steel frame can be built that will support stucco or stone-faced walls and a roof allowing for the 'box' to filled with loose vermiculite.
Once the oven is finished none of the frame needs to show and the outside of the oven is cool to the touch even when the inside temperature is 800 degrees.

Sunday, May 1, 2011

Brick Oven Dome Building, Part 3

There is a point in building the dome when gravity prevents mortaring bricks without a form. Foam insulation was cut in curved wedges to support the succeeding chains of bricks.  This form rests on pieces that can be removed later through the oven mouth. The maximum size of each piece is determined by the width and height of the mouth.

As building progresses, wood wedges are used to tilt the bricks at the appropriate angle so that the dome shape conforms to the desired height. Once the wedges are removed the cavities are filled with refractory mortar and the wedges reused on the upper courses.  Bricks are cut at increasingly sharper angles and decreasing widths so that the radius of the chain is followed.

The goal at the top of the dome is to close the remaining space with a final key stone that applies outward and downward pressure on all the bricks.
This is what makes the dome shape stable as it expands and contracts in firing.