Part IV
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Miscellaneous
MISCELLANEOUS
HEATING OVENS
BY PROF. E. W. HABERMAAS
Proceed to heat the oven as follows: Free the grate of ashes and clinkers, then put the wood (which should be thoroughly dry) in the furnace; then put some paper in the furnace and light it; then open the damper and the draft door. When using coal for fuel, put some dry wood in the furnace, then put coal on it and light it, then draw the damper and open the bottom draft door. Now watch your fire, adding fresh fuel. When about one-third of the fuel is burned, fill the furnace with as much fuel as it will hold, then close the door; continue this process about three times. When the last furnace of fuel has burned down about one-half, close the damper partly (to prevent the heat from escaping through the open flue) and as the fire continues to burn down, continue closing the damper, and when the fire has burned down completely, close the damper entirely and shut the bottom draft door. The oven should be fired at least one hour before you begin baking in it, to allow the heat to moderate and to become evenly distributed throughout the oven, producing what is known to the trade as a ground heat. If you bake in a freshly heated oven your goods will scorch on the outside and remain doughy inside. Some goods require a very quick oven, but the first heat in a fresh oven (providing the oven has been properly heated) is almost too hot for any class of goods. If you are compelled to bake in a freshly heated oven, open the damper and allow the oven door to remain open while baking, thus allowing a portion of the excessive heat to pass into the flue. This first heat is called flash heat, because it is not a lasting heat. An oven may be overheated or underheated to a degree as to render it unfit for service. Bakers should be very careful about heating their ovens. Little fuel can be used and excellent results obtained, providing the one who does the firing knows how to fire an oven. Follow our directions very carefully when firing ovens. If you have too much heat in your oven you can remedy that by drawing the dampers and leaving the oven door open. But if you have an underheated oven you will find that the only remedy is to build more fire. This is wasteful extravagance, though sometimes it is difficult to avoid, especially when you have damp or green wood. There is also a flash heat in an underheated oven, but it is not intense, nor does it last very long.
On the other hand, if the bottom draft and furnace doors are not air tight, though you have them closed and have the dampers open, and only a moderate breeze is blowing, the fire will burn briskly. If you want the fire to die, close the damper and the bottom draft door. When you close the damper and the bottom draft door you shut off the supply completely, or the life of fire, then it dies. Chimneys should be built to tower above the roofs of adjoining buildings, so that the air currents can pass over them unobstructed.
We have shown above that it is necessary to supply fire with air to create combustion, so we will now show what is understood by combustion.