A liqueur is a sweetened infusion of herbs, spices and or fruit. The process of manufacturing liqueurs varies as it is dependent on the ingredients used. The process can normally be split up into two styles. The first is Infusion or Percolation. Both techniques mix spirit with the flavouring material and allow the flavours to leach. Percolation does this more actively by forcing the alcohol repeatedly through the material, often as a vapour. The length of time for each process depends on the amount of flavour required from each ingredient. Other liqueurs are distilled in the manner of gin with the ingredients being added to a still and the resultant distillate containing some of the flavours collected. The spirit is then left either to marry in steel tanks or in many cases to be aged in wood.