The majority of small, mechanical-percolation brewers designed for the domestic market double up the heating element as a means of keeping the brewed coffee hot, in addition to heating the water for brewing. The element is usually made of an aluminium or brass block in the shape of a horseshoe. It is typically positioned under the foot of the brewer, below the decanter. A thin layer of insulation is usually positioned here to reduce the impact of excessive heat degrading the coffee flavour. This technology is not an accurate means of maintaining a brew in the 80–85°C range, in which the chlorogenic acids component remains more stable, however.
Illustration: An aluminium block in the shape of a horseshoe running underneath where the decanter sits on the hotplate.