Dr. Carien Coetzee
Basic Wine
30 July 2021
The effect of shipping conditions on wine quality was the focus of two blog posts previously published on the Sauvignon Blanc SA website. Part 1 of the above-mentioned blog series summarized results obtained from a study investigating the impact of temperature during bulk wine shipping while Part 2 looked at the impact of simulated shipping temperatures on South African Sauvignon Blanc sensory composition.
Many studies have investigated the effect of temperature on wine composition and quality and it is evident (as with many other foods and beverages) that temperature is the most important factor to consider. Producers and consumers are often surprised by the harsh conditions carefully crafted wines need to endure (and survive) before it reaches the retailers. The detrimental effect of elevated and fluctuating temperatures during wine transport and storage are well described, however other factors such as light exposure, humidity and agitation also needs attention. The main findings of two published studies looking at the effect of vibration and agitation on wine are summarised below.
Vibration
A 2008 study1 noted that excessive vibration during wine storage results in a number of undesirable issues. In this study, wines were aged under four different vibration intensities for 18 months.
Main results
Continuous vibrations resulted in significant changes in the physico-chemical properties of the tested wine. The presence of vibration substantially accelerated the evolution of the wine and the changes in physico-chemical properties became more significant at higher vibration levels. Some of the main findings in this study:
- The total acidity increased slightly with ageing up to 9 months. This increase was more substantial at the highest vibration level than at the lower vibration levels.
- The concentrations of tartaric and succinic acids decreased during vibrated storage.
- Refractive index increased during the first 3 months and thereafter it remained constant.
- Changes in organic acids and refractive index were accelerated when the wine was stored at higher levels of vibration than at lower levels of vibration.
- Propanol and isoamyl alcohol contents were higher in the wine stored at low levels of vibration.
Agitation
A study2 performed at Geisenheim University simulated the conditions experienced during an actual shipment from Germany to Japan. Temperature fluctuations were monitored and the data recovered were used to simulate the conditions experienced during the transport by adjusting the conditions in a climatized cabinet. The time and temperature settings of the simulation was thus based on real transport situations.
Two different simulations were applied. One simulation was recorded during the European summer months (May/June), while the second simulation was recorded during the European winter months (February/April). What makes this study particularly interesting is that they not only applied a temperature simulation, but they also included an agitation treatment. Some of the wines were agitated during the simulation using a vibrating table set at 100 Mot/min for 60 minutes. This treatment was applied three times during the simulation period.
The wines from the simulated conditions were compared to a control wine which was held at a constant storage temperature (15°C) without any movement/agitation.
Summer simulation settings
- Transport duration 50 days
- Minimum temperature approximately 15°C
- Maximum temperature approximately 45°C
- Temperature difference approximately 30 °C
Winter simulation settings
- Transport time 69 days
- Minimum temperature approximately -10°C
- Maximum temperature approximately 30°C
- Temperature difference approximately 40 °C
Main results
- Chemical analyses showed no significant differences between the treatments for the following wine parameters: extract, sugar-free extract, fermentable extract, glucose, fructose, total acidity, pH, tartaric acid, malic acid, lactic acid, citric acid, glycerol, alcohol. The sulphur dioxide content of the wines also did not differ significantly between the treatments. Compared to the control the wines transported in the summer months were only slightly lower in sulphur dioxide content.
- A decrease in bottle weight (sealed with a cork) was observed for the wines transported in the summer months. The decrease was observed especially during the first and last 10-15 days which seems to correspond to times of extreme temperature fluctuations.
- Even though the control sample was rated as the wine with the most “fresh and fruity” characteristics, it did not differ significantly from the winter simulated wines (both agitated and static) as well as the summer simulated wines (static only). The summer months simulation with agitation resulted in wines with significantly less “fresh and fruity” aromatics.
Conclusion
Even though temperature remains the main problem during transport and storage, the physical movement (vibration and/or agitation) of the wine can also have an effect. It seems that wine agitation during spells of fluctuating temperatures altered the sensory properties of the wine. These effects were less when lower temperatures are experienced.
Using express services to get your wine to its destination faster will not only reduce the amount of time that the wine may be exposed to elevated or fluctuating temperatures, but it will also reduce the amount of time that the wine is exposed to movement/vibration/agitation.
References
(1) Chung, H.-J.; Son, J.-H.; Park, E.-Y.; Kim, E.-J.; Lim, S.-T. Effect of Vibration and Storage on Some Physico-Chemical Properties of a Commercial Red Wine. Journal of Food Composition and Analysis 2008, 21 (8), 655–659. https://doi.org/10.1016/j.jfca.2008.07.004.
(2) Jung, R.; Leyh, B.; Dieter Patz, C.; Rothermel, A.; Schuessler, C. Potential Wine Ageing during Transportation. BIO Web of Conferences 2014, 3, 02004. https://doi.org/10.1051/bioconf/20140302004.
Photo by Louis Hansel on Unsplash
