Another type of briquetting machine is the hydraulic piston press. This is different from the mechanical piston press in that the energy to the piston is transmitted from an electric motor via a high pressure hydraulic oil system. This machine is compact and light. Because of the slower press cylinder compared to that of the mechanical machine, it results in lower outputs. The briquettes produced have a bulk density lower than 1,000 kg/m3 due to the fact that pressure is limited to 40-135 kg/h. This machine can tolerate higher moisture content than the usually accepted 15% moisture content for mechanical piston presses. Pelletizing is closely related to briquetting except that it uses smaller dies (approximately 30 mm) so that the smaller products produced are called pellets. The pelletizer has a number of dies arranged as holes bored on a thick steel disk or ring and the material is forced into the dies by means of two or three rollers. The two main types of pellet presses are: flat and ring types.

Large capacity pelletizers are available in the range of 200 kg/h-8 ton/h. Thus, pellet press capacity is not restricted by the density of the raw material as in the case of piston or screw presses. Power consumption falls within the range of 15-40 kWh/ton.