r. Aborn expressed himself as follows on
the filtration method:

The filtration method is not new, but well tried, thoroughly proven
and long used, though often incorrectly. It is the method followed,
more or less correctly, by all of the first-class hotels in the
world. It is controlled by no patent or proprietary device, and
requires a most inexpensive equipment. For a perfect result it but
demands an accurate adherence to simple but vital principles.
Deviations from these fundamentals, though apparently slight, cause
failure. When they, and the necessary _exact_ following of them,
are clearly understood, any person, even a small child, can brew
coffee with unvarying success.

The first point to consider in filtration is the dimensions of the
filter bag, or container of the ground coffee, in relation to the
quantity of coffee used and the granulation of same. If the filter
be a muslin bag, free on all sides, the filtering surface is
considerable and permits the necessary quick passage of water
through the grounds, provided the bag is of a wide enough diameter
as to prevent too great a depth of grounds through which the water
cannot quickly penetrate. The error of too narrow a filter is a
common one. It causes a delayed filtration, which means undesirably
long contact of water and coffee and also the cooling of the liquid
which in a correct, undelayed filtration is smoking hot at
completion. The bag should also not be too long or be allowed to
hang or soak in the liquid. A filter bag set tightly into a pot
against its sides, thus surrounded with impenetrable walls, is
greatly reduced in filtering surface, and the filtration is thereby
slackened.

The filter material should not be too coarse in texture, like
cheese cloth, or too heavy and impenetrable, like very heavy
muslin. A moderate weight muslin, not too light, is efficient.

The degree of granulation also, of course, affects the rate of
flow. The coarser the grind the faster the flow, which permits a
larger quantity of coffee to a given diameter of filter bag.

A most frequent fault in the use of the filtration method is the
failure to understand the fine degree of grinding necessary to the
best results. When the grind is not sufficiently fine the
extraction is, of course, weak. A f