Extract Measurement by Density or Sound Velocity


EXTRACT MONITOR is a variant of RHOTEC or SONATEC and used in the brew house of the brewery.

Typically, the extract measurement is done during lautering and wort boiling. The instrument uses the functionality of either RHOTEC (density measurement) or SONATEC (sound velocity measurement) and is designed for applications requiring maximum sensitivity and highest accuracy. It is easy to operate and maintenance-free.

The density measurement is based on the oscillating U-tube principle. For sound velocity measurement a sound pulse is created by a sonic transmitter and detected by a sonic receiver. As a specific property of each liquid, the correlation between concentration and density resp. sound velocity can be described by a mathematical polynomial.

With decades of experience and our own laboratory facilities, Centec know the polynomials for a large number of products. Any temperature drifts of the measured signal are automatically compensated for.

Typical Technical Data

  • Measuring Range

    0 - 30 °Plato

  • Accuracies

    ±0.03 °Plato - RHOTEC
    ±0.07 °Plato - SONATEC

  • Temperature of Product during the Measurement

    140°F to 217°F (+60°C to +103°C)

  • Response Time


  • Pressure of Operation

    max. 16 bar

  • Temperature of Operation

    -13°F to 257°F (-25°C to +125°C) (Pt1000)

  • Material

    1.4404/1.4435/AISI 316L; Hastelloy; Tantalum; etc.

  • Profibus DP


  • Enclosure Rating


  • Power Supply

    24 VDC


  • Very accurate determination of extract in the brewing process
  • Patented compact design with local display available
  • Hygienic execution; various materials and flange connections