Percolation (technique)
The percolation (from Latin "percolare" -. Oozing) describes the through-flow of water through a solid substrate . Here to minerals extracted or like to be; the washed-out particles are called percolates . Percolation is also known as seepage leaching .
This term is mostly used in hydrology , where it includes water that seeps through the soil . Percolation only occurs when the field capacity , i.e. the maximum water storage capacity of the soil against gravity, is exceeded. If this happens over the entire thickness of the unsaturated zone (vadose zone), new groundwater is formed .
In pharmaceutical technology , percolation is used to obtain active ingredients from plants. A mostly warm solvent , such as water or alcohol , is passed through the plants or plant parts; in laboratory practice mostly with the help of a Soxhlet attachment . A well-known example of percolation is also the preparation of filter coffee . If several percolators are connected in series (in practice up to five), this is also referred to as recolation .
In the production of spirits , percolation means the extraction of drugs through “displacement”. Cylindrical vessels made of copper or stoneware are used for this, tapering towards the spout. The crushed drugs are placed in the percolator between two sieves and the 30-60% ABV make-up spirit is added to it. The fuel diffuses and accumulates within a few days with the alcohol-soluble substances in the drugs. After 3–6 days the pre-percolate is slowly drained off. At the same time, liquor continues to be poured in via the inflow until the constituents of the plant parts have essentially been extracted. This is followed by post-percolation, in which an attempt is made to squeeze out the remaining fuel by adding water.
See also
Web links
- Entry to wood saccharification. In: Römpp Online . Georg Thieme Verlag, accessed on 2018-10-12.
- Percolator with an explanation of the percolation in the extraction of drugs
- Entry on percolation. In: Römpp Online . Georg Thieme Verlag, accessed on 2018-10-12.