Choose as small a portable oven as will hold the food to be cooked,
since the larger the oven the larger or more numerous the stones must
be to heat it. Very large stones are heavy and awkward to manage, and
with their number the cost of using the oven increases. A portable oven
is on the market which is about thirteen inches in each dimension. This
is a good size for a family of four or five. Cut six pieces of heavy
sheet asbestos, fitting one to each surface of the oven, except the
door, and two to the bottom. One of the two pieces for the bottom is to
go inside the oven. Place the asbestos so that it entirely covers the
oven. These pieces may be tied on temporarily to hold them in place
during packing. Select a box which is at least two or three inches
larger in every dimension than the corresponding dimension of the oven.
It should be fitted with cover and hasp just as any cooker. Lay it,
while packing, with the cover opening upward. Pack in the bottom a
sufficient layer of insulating material, such as is used for other
cookers, to raise the oven to within a couple of inches of the top.
Place the oven, lying upon its back, on this layer with the door
uppermost, and opening in the same direction as the cover of the box.
Pack on all sides around it till level with the door.
If desired, a facing may be made to cover the packing material, from a
piece of cloth cut a few inches larger, in each direction, than the top
of the box. Draw on it a square the size of the oven. In the centre of
this cut a small hole to insert the blade of scissors. From this hole
cut diagonally to the corners of the square. When the cloth is put in
place over the packing the triangular flaps thus made may be tucked
between the asbestos and the packing, while the edges of the cloth may
be tucked between the packing and the sides of the box. Fit a cushion
that will fill the space left at the top and nail it to the cover of the
box. Face this with a piece of the sheet asbestos nailed into place. It
will be well to reinforce the nail-heads with little rounds of tin, in
order to prevent them from pushing through the soft asbestos. The box is
then ready for use and should be stood up on end so that the cover will
open like a door, and the oven will be right side up. The extra piece of
asbestos may be laid in the bottom, the stones heated, and the food put
in to cook.
_Method of using the oven._ Heat the slabs very gradually the first time
that they are used. It will be best to put an asbestos mat or piece of
the sheet asbestos between a hot gas flame and the stones for a few
minutes, not turning the gas on full force for the first five minutes.
After the first using it will be safe to heat the stones directly over
the flame, providing it is not burning with full force for the first few
minutes. The degree of heat in the stones will regulate the heat of the
oven. For most baking, the centre of the top side of the stones should
be about as hot as a flatiron for ironing. This will mean that the side
toward the flame is very much hotter, perhaps red hot. Another and
better test is the browning of a piece of white tissue paper laid on the
centre of the stones when they are put on to heat. When this grows a
shade darker than manila paper, or a golden brown, the stones are right
for loaf cakes, pastry, apples, potatoes, beans, scalloped dishes, most
puddings, and bread. For a hot oven the paper should be a rich brown.
This is suitable for biscuits, small cakes, roasting meat, etc.
Although gas is the fuel here mentioned any other fuel will serve to
heat the stones, provided a hot enough flame can be procured. The stones
may, when warmed, be set directly on a hot coal or wood fire to complete
the heating, and, for out-of-doors use, a crude fireplace might be built
up of rough stones to support the soapstones or they may be buried
directly in the hot coals. In such a case it will probably be necessary
to have some device, perhaps ice-tongs, for removing the stones, as the
metal handles might in time become burned off, bent, or weakened so as
to be unsafe.
Small soapstone griddles or foot-warmers make excellent slabs for the
home-made insulated oven. Griddles are on the market that are as small
as twelve inches in diameter, and foot-warmers come in many sizes. Those
measuring eight by ten inches will be about as large as most women can
easily handle, since they are thicker than the griddles, and are very
heavy for their size. It will not be difficult to get an extra handle
fitted to these, which will make them less awkward to manage. For baking
many loaves of bread and cake, and for foods to cook over night, or for
many hours, more than two stones may be necessary to maintain enough
heat.
The oven should not be opened during the baking, but if the food is not
found to be cooked when it is opened, it may be quickly closed again,
and left till the food is done. A succession of articles may be baked in
an already heated oven by quickly removing the finished article and one
or two stones to be reheated and tested, and slipped again into place.
In this case the door of the oven should be instantly closed after
removing anything from it. This method of baking a number of things in
quick succession is very economical as a few minutes will reheat the
already warm stones.
Lay one hot stone on the asbestos at the bottom of the oven with the
hotter side down; put a wire oven shelf on this, and the food on the
wire shelf. If the food will not rise higher than the top of the pan, a
hot stone may be laid directly across the pan, but if this is not
possible place the second wire shelf as close over the food as the
cleats at the side of the oven will permit, and the stone on this shelf,
also with the hot side down. In case more than one pan is to go in at
once, and two stones will not supply enough heat, hot flatirons or stove
lids may be used to supplement them. It is often convenient, when the
oven is heated for baking one article, to put other things in to cook at
the same time, even though they may not require browning. For instance:
A chicken or roast may be cooking between two stones, while on top of
the upper stone the giblets may be stewing in water, or some vegetables
be boiling. It will be best in such cases to heat these foods till
boiling before putting them in the oven, or they will cool it too much.
Such foods, as do not require browning, will not need another stone on
top. It may not be wise to put so much watery food in the oven when
baking anything so critical as bread or loaves of cake, as it cools the
oven to some extent.
No matter how carefully the directions are given and followed some
experimentation will probably be required before a novice, or even an
experienced cook, will feel at ease with this new method of cookery,
since the conditions may be so variable. But there is no reason why a
careful observation of results and their causes should not soon lead one
to become mistress of her own insulated oven, and it is likely that she
will then become sufficiently attached to it to justify her
perseverance.
In case a cooker-pail is to be utilized for baking it will be well to
surround it, on top, bottom, and sides, with the heavy sheet asbestos
described for insulating the oven. A wire rack will be needed for
separating the food from too direct contact with the hot stones, and
some device, such, perhaps, as an inverted wire frying-basket for
supporting the upper stone.