The Role of CO2 Measurement in Wine Production
Edinburgh Sensors: Fermentation, the chemical process that uses yeast to convert sugars to ethanol, is at the heart of the winemaking process. Temperatures and conditions in wineries are very carefully controlled to ensure that fermentation does not occur too fast, distorting the flavour and alcohol content of the wine. The type of yeast used for a particular wine is also chosen for its influence on the fermentation process, including the concentrations of chemical side products from fermentation that influence the final flavour profile.1
As well as ethanol, gaseous carbon dioxide is generated as a natural part of the fermentation processes. However, as wineries are typically built in small, enclosed spaces, CO2 can pose some serious health and safety risks. As CO2 is heavier than air the CO2 will pool on the floor and displace oxygen, creating an asphyxiation risk, particularly in poorly ventilated areas. As it is colourless and odourless, CO2 leaks can remain unnoticed until concentrations are sufficiently high to cause symptoms such as dizziness, headaches and raised heart rate and, later, have potentially fatal consequences.2
In Great Britain, as CO2 has been classed ‘substance hazardous to health’ since 2002, it is a legal requirement to have CO2 detection and alarm systems3 and it is encouraged to have concentration monitoring in place to ensure workplace exposure does need to exceed the safety limits.4 Most US states have similar rules on short- and long-term exposure to CO2, with the National Institute for Occupational Health and Safety indicating that CO2 levels of 40 000 ppm (4%) are immediately dangerous to life and health.5
Areas of the winery that are particularly hazardous in terms of CO2 production are the storage tanks, fermentation rooms, barrel cellars, and bottling rooms. The use of open fermentation vessels in production poses a particularly increased asphyxiation risk as the headspace above the tank may reach CO2 concentrations of 100 %.6
CO2 concentrations are not just a safety issue in winemaking though. The dissolved CO2 concentration wine has obvious importance for sparkling wines but has a strong influence on how the wine hits the palate.7 Given the sensitivity of CO2 production to other variables, like temperature and the frequency of racking, the concentration can change rapidly, making on-line process monitoring also of interest as a means of quality control and assurance.
This is why many wineries are already turning to Edinburgh Sensors instruments to allow continuous, on-line monitoring of CO2 levels.8
CO2 Detection Range
Edinburgh Sensors offer a range of instruments ideal for CO2 gas detection and monitoring. Drawing on their expertise in designing non-dispersive infra-red sensing instruments, they offer a range of products ideal for use in winemaking premises.
One low-cost solution is the GasCheck CO2 sensor.9 There are three ranges of instruments with different specifications to meet the exact needs of the customer, but all are capable of detecting CO2 concentrations between 0 – 3000 ppm. This sensitivity allows detection of small leaks, at concentrations below the short-term exposure limit which is 5000 ppm over an eight-hour period.4 With a robust design based on analogue electronics and zero-stability of ± 3 % over 12-months, the GasCheck can be relied on to operate with minimal interference. Its measurements are also unaffected by 0-95 % relative humidity, making it suitable for use in all areas of the winery.
As well as the GasCheck, Edinburgh Sensors also offers the Boxed GasCard and IRgaskiT for your CO2 sensing needs. All of these monitors can be connected to logging software and alarms and are capable of continual, online monitoring. This eliminates the need for personnel to perform time-consuming, manual checks as well as ensuring there are no gaps between gas measurements. The continual data logging also makes it easier to monitor that the CO2 concentrations adhere to the lower, long-term exposure limits.4
The IRgaskiT is a small device, weighing in at 125 g, that offers advanced integration possibilities into other systems.10 This could include systems such as the ventilation, where if the CO2 concentration exceeds a predefined threshold the ventilation will automatically open to exhaust CO2 and retain the oxygen levels. It is also capable of measuring up to 0 – 100 % concentrations of CO2 and operating at atmospheric pressure, up to 95 % humidity, with no adverse effects on measurements.
Edinburgh Sensors has developed their very popular CO2 detection instruments, the GasCard NG, into a new convenient and robust desktop unit, the Boxed GasCard.11 Like the IRgaskiT, there are a number of logging and interfacing options, including an RS232 connection for external control. It offers unparalleled measurement accuracy of ± 2 % over ±<0.015% of range per mbar even at pressures as low as 800 mbar. All it requires is a power supply and sample gas to be up and running. The boxed design makes it straightforward to use as a remote sensor, perhaps in lower regions of the winery like basements where CO2 accumulation is a particular risk and the excellent detection range for CO2 from ppm to tens of percent ensures that worker safety will never be compromised.
All of Edinburgh Sensors products come with access to their technical support and advice both before and after purchase.
- P. J. Chambers and I. S. Pretorius, EMBO Rep., 2010, 11, 914–920
- N. J. Langford, Toxicol. Rev., 2005, 24(4), 229-235
- Law on Hazardous Chemical Substances, https://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CELEX:31998L0024:en:HTML, (accessed February 2019)
- HSE on CO2, http://www.hse.gov.uk/carboncapture/carbondioxide.htm, (accessed February 2019)
- NIOSH Guidelines, https://www.cdc.gov/niosh/docs/76-194/default.html, (accessed February 2019)
- Monitoring Gases in the Wine Industry, https://www.gmiuk.com/application-notes/monitoring-gases-in-the-winery-industry/, (accessed February 2019)
- Carbon Dioxide in Wine, https://winesvinesanalytics.com/columns/section/24/article/86529/Carbon-Dioxide-in-Wine-Its-a-Gas, (accessed February 2019)
- Gas Sensors for Winemaking, https://edinburghsensors.com/news-and-events/carbon-dioxide-levels-and-safety-considerations-in-winemaking, (accessed February 2019)
- GasCheck, https://edinburghsensors.com/products/oem/gascheck/, (accessed February 2019)
- IRgaskiT, https://edinburghsensors.com/products/oem/irgaskit/, (accessed February 2019)
- Boxed GasCard, https://edinburghsensors.com/products/oem/boxed-gascard/, (accessed February 2019)