50. VARIETIES OF COAL.--Possibly the most common fuel used for cooking
is coal. This fuel comes in two varieties, namely, _anthracite_, or
_hard coal_, and _bituminous_, or _soft coal_. Their relative cost
depends on the locality, the kind of stove, and an intelligent use of
both stove and fuel. Hard coal costs much more in some places than soft
coal, but it burns more slowly and evenly and gives off very little
smoke. Soft coal heats more rapidly than hard coal, but it produces
considerable smoke and makes a fire that does not last so long. Unless a
stove is especially constructed for soft coal, it should not be used for
this purpose, because the burning of soft coal will wear it out in a
short time. The best plan is to use each variety of coal in a stove
especially constructed for it, but if a housewife finds that she must at
times do otherwise, she should realize that a different method of
management and care of the stove is demanded.
51. SIZES OF COAL.--As the effect of coal on the stove must be taken
into consideration in the buying of fuel, so the different sizes of hard
coal must be known before the right kind can be selected. The sizes
known as _stove_ and _egg coal_, which range from about 1-3/8 to 2-3/4
inches in diameter, are intended for a furnace and should not be used in
the kitchen stove for cooking purposes. Some persons who know how to
use the size of coal known as _pea_, which is about 1/2 to 3/4 inch in
diameter, like that kind, whereas others prefer the size called
_chestnut_, which is about 3/4 inch to 1-3/8 inches in diameter. In
reality, a mixture of these two, if properly used, makes the best and
most easily regulated kitchen coal fire.
52. QUALITY OF COAL.--In addition to knowing the names, prices, and uses
of the different kinds of coal, the housewife should be able to
distinguish poor coal from good coal. In fact, proper care should be
exercised in all purchasing, for the person who understands the quality
of the thing to be purchased will be more likely to get full value for
the money paid than the one who does not. About coal, it should be
understood that good hard coal has a glossy black color and a bright
surface, whereas poor coal contains slaty pieces. The quality of coal
can also be determined from the ash that remains after it is burned.
Large chunks or great quantities of ash indicate a poor quality of coal,
and fine, powdery ash a good quality. Of course, even if the coal is of
the right kind, poor results are often brought about by the bad
management of a fire, whether in a furnace or a stove. Large
manufacturing companies, whose business depends considerably on the
proper kind of fuel, buy coal by the heat units--that is, according to
the quantity of heat it will give off--and at some future time this plan
may have to be followed in the private home, unless some other fuel is
provided in the meantime.
Mixed with poor coal are certain unburnable materials that melt and
stick together as it burns and form what are known as _clinkers_.
Clinkers are very troublesome because they often adhere to the stove
grate or the lining of the firebox. They generally form during the
burning of an extremely hot fire, but the usual temperature of a kitchen
fire does not produce clinkers unless the coal is of a very poor
quality. Mixing oyster shells with coal of this kind often helps to
prevent their formation.
53. COKE.--Another fuel that is sometimes used for cooking is coke.
Formerly, coke was a by-product in the manufacture of illuminating gas,
but now it is manufactured from coal for use as a fuel. Because of the
nature of its composition, coke produces a very hot fire and is
therefore favorable for rapid cooking, such as broiling. However, it is
used more extensively in hotels and institutions than in kitchens where
cooking is done on a small scale.