CHAP. XV.Of the Filtration of Liquors.
Filtrationconsists in passing Liquors thro’ some porous Substance, in order to free them from those Particles which obscure their Brightness.
Nothing is finer than a Liquor newly distilled; but the Syrup and colouring Particles render it thick and opaque; in order, therefore, to restore their Brightness they are filtrated, which is done by passing them through Sand, Paper, Cloth,&c.
All the Attention of the Distiller cannot in ordinary Operations always prevent some aqueous Particles from rising with the Spirits, either in the Beginning of the Process, in those Compositions where they ascend first, or at the Conclusion when they rise last. As this is almost unavoidable, so it is also sometimes necessary.
In distilling Flowers, or aromatic Plants, fresh gathered, the Phlegm rises first; and this Part cannot be taken out of the Receiver without depriving the Spirits of a considerable Part of their Fragrancy.
In distilling Spices, their Odour being more entangled, will remain in the Alembic till Part of the Phlegm is drawn off. But when, instead of these Substances, their Quintessences are used, the Necessity ceases. But the Phlegm commonly causing a Cloudiness in the Liquor, it may be rendered tolerably fine, by pouring it gently off by Inclination, without the Trouble of Filtration the aqueous Particles, by their Gravity, falling to the Bottom. But to render it entirely bright and fine, put some Cotton in a Funnel, and pour the Liquor thro’ it, by which means the aqueous Particles will be retained in the Cotton. You must however remember to cover the Top of the Funnel, to prevent the most volatile Parts of the Spirits from evaporating.