As the festive season gets underway wine drinkers on Earth are set
to benefit from a technology under development to feed astronauts on
missions to Mars. A company based near Barcelona, Spain is using a
sensor, developed under a European Space Agency programme, to improve
control over the production of the sparkling white wine, Cava. When
humans eventually begin to explore and colonise Mars, the sensor will
have a crucial role to play in controlling a process to recycle food
and other consumables.

Wine is made by fermenting grapes with yeast to produce alcohol and
carbon dioxide. To produce good quality wine, it’s important to control
the growth of the yeast. "If we want to know how the yeast is doing,
now we have to take a sample from each fermentation vat to the lab and
count the yeast under a microscope," says Pilar Urpi from Freixenet,
Barcelona. "The new sensor will tell us instantly at any time how much
yeast we have," she adds.

Sensors to determine the concentration of yeast or other microorganisms
in a liquid have, until now, relied on measuring the intensity of light
shone through the liquid. Such methods, however, have been inaccurate
at high concentrations and when air bubbles or clumps of microorganisms
are present. This new sensor overcomes such problems by measuring the
electrical rather than optical properties of the fermenting wine to
derive the concentration of yeast.

From January, Freixenet will begin installing a sensor into each
of its fermentation vats. The result should be a better-controlled
fermentation process and hence improved quality of the wine.

The sensor was originally developed as part of ESA’s Melissa project,
which is investigating ways of recycling food, oxygen and water on long
manned space missions. The sensor controls the fermentation of ammonia
into nitrate in the third of five compartments in the Melissa system.

Companies from all over Europe are contributing towards Melissa. NTE, a
company in Barcelona specialising in the development of new technology
for space, has developed the sensor. "When we work for ESA, we always
end up developing some new technology because the requirements for
space are very strict. We then go looking for terrestrial applications
and often find several," says Jordi Elvira, project manager from NTE.

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[Image 1:]
Wine drinkers on Earth will benefit from a technology under development
to feed astronauts on missions to Mars. A company near Barcelona is
using a sensor developed under an ESA programme, to improve control
over the production of the Spanish sparkling wine, Cava.

[Image 2:]
Microscope counting of viable yeasts in samples extracted from
fermentation vats at Freixenet.

[Image 3:]
Fermentation vats for the first fermentation process at Freixenet. The
second fermentation is taking place at every bottle in the cellar.
After the second fermentation, the CAVA is ready.

[Image 4:]
Probe of the Biomass Measurement System developed by NTE to be installed
in fermentation vats at Freixenet. This probe is mounted into the vat
through a standard connection port. A front-end electronics box remains
outside of the vat.