On-Line Measurement of Plato Degree during Beer Fermentation Using SMAR DT302 Density Transmitter
The Beer Fermentation Process
Fermentation is the process through which fermenting
carbohydrates are converted by yeast into alcohol, carbon
dioxide and other by-products. The fermentation process is
dependent on the composition of the must, yeast and process
conditions. Factors affecting fermentation conditions include
time, must temperature, volume, fermentation vessel design,
pressure, agitation and must currents.
Plato Degree is used to effectively monitor and control the
beer fermentation process. Plato Degree is a concentration unit,
and is defined as the percentage of saccharose mass present in
Continuous and On-line Plato Degree
The DT302 Density and Concentration Transmitter is a device developed by SMAR for continuous, on-line
measurement of liquid density and concentration in industrial
The DT302 uses the principle of differential hydrostatic
pressure (d=Δp/g.h) to calculate the process fluid density. It is a
patented instrument containing a probe, immersed in the process fluid with two pressure sensors and one temperature sensor, the
latter being used to automatically compensate for any variation
in the process temperature.
The unique design and assembly of the pressure and temperature sensors make it possible for small variations in the process to be instantly detected and translated into a high accuracy density measurement.
Once the process fluid temperature and density are known, the
Plato Degree can be calculated. The transmitter then supplies
an output signal proportional to the calibrated range to be used
to monitor and control the beer fermentation process.
The installation of the DT302 is made directly on the
fermentation tank. SMAR has developed an adaptor that can be
installed in new or existing tanks to eliminate any unnecessary
welding or maintenance to the tank.
The following illustrates the tank adaptor for installation of
the Density Transmitter:
The sanitary model density transmitter is recommended
for brewery installation and uses a tri-clamp connector for
The probe shape was specifically designed to allow for CIP
cleaning without the need to remove the instrument from the process. The external finishing complies with the FDA
norm 3A requirements. The DT302 is an integrated unit,
without remote electronics. Information for identification,
configuration, range adjustment and diagnostics may be
accessed remotely through configuration and diagnostic tools.
The DT302 is a two-wire loop powered device with
Foundation Fieldbus communications protocol. It is also
available with HART and Profibus communications. As a
digital device, the instrument is capable of providing extensive
amounts of process information, including Plato Degree and
process temperature. As this information is available digitally,
there are no errors in the transmission of the information.
On-Line DT302 and Beer Analyzer Results Comparison
The on-line DT302, with a direct Plato Degree output, allows
simple, accurate, and reliable control of the fermentation
process. Especially when compared to grab sample and lab
On-line measurement provides real time process information
and allows for immediate operator interaction to maintain
product quality and consistency. This minimizes the losses and
snap shot samples normally incurred during sampling.
The DT302 indicates the exact moment when the
fermentation process ends and the batch is ready. The
DT302 also helps in the maturation process by managing
the refrigeration process and consequently optimizing the
power requirements. The following is an actual comparative
analysis between on-line Plato Degree measurements done
by the DT302 and a beer analyzer. The comparisons were
made at a lab, as the analyzer sample needs to be filtered,
and decarbonated before measurement can be made.
There are many significant advantages for using the SMAR
DT302 Density Transmitter during the beer fermentation
process. These include:
- Real-time continuous measurement of Plato Degree,
density, and temperature compensated volume;
- Real-time measurements allow for automation of the
- Reduced power consumption in the refrigeration system;
- Elimination of product losses and sampling errors;
- Increase in process reliability, ensuring greater end-product
uniformity and quality.
Testimonial: Eng. Homero Guercia - Industrial Manager, Schincariol - Cachoeiras de Macacu - RJ
"After several months of operating SMAR Density Transmitters on the fermentation tanks, we experienced an improvement in the quality of
our production process as well as improving product quality through
the continuous measurement of Plato Degree.
The continuous measurement of Plato Degree enabled to precisely
trigger when we start our maturation process and consequently,
significantly reduce our power costs.
We were also able to increase production, as we no longer needed to
sample off-line, which we had found contributed to added time, labor
and waste to our production process".