29 March 2022
Specialists from Omnivent Techniek UK Ltd share their advice
WINTER is already coming to an end, and we are currently dealing with relatively high temperatures and cold nights. There are several things in the storage that need attention.
Limit internal ventilation in cold weather
Internal ventilation at night with frost leads to extra cold in the storage, in the case of less insulated hatches. This creates temperature differences that can cause condensation. To prevent this, short-term internal ventilation in the middle of the day is the best alternative.
Consider whether internal ventilation is necessary; if the product is dry, internal ventilation will lead to unnecessary moisture loss from your products. Furthermore, after external air ventilation, there is always after ventilation, which is also a form of internal ventilation. This could be limited.
Also, the temperature difference between the sensors – which must be below 1°C after 2 months – does not require internal ventilation.
If it is much colder outside than inside in your storage, condensation on the roof or trusses can occur. That is a big problem because the condensed water causes droplet formation, and can eventually cause rot in the stored product. Especially in buildings with poor roof insulation, this phenomenon will certainly cause damage.
Solution for condensation!
Circulation fans keep the air above your potatoes moving when the system fans are off. This reduces the risk of condensation. If the circulation fans are equipped with a heating element, condensation no longer stands a chance at all.
-No condensation = less rot risk!
-Reduced operating hours of system fans to prevent condensation. That means: less energy consumption, lower costs, and less dehydration (and therefore weight loss),
-less rot and therefore lower storage losses
Refresh with outside air
Due to the high temperatures during the day, it will not be possible to use outside air to cool, but at night this should be possible without problems. Pay attention to the set dew point difference and remember that -0.5°C is the lowest minimum value. The maximum dew point difference can be set to -8°C.
To keep the potatoes calm, it is advisable to keep a close eye on the CO2 values, set the minimum outside temperature at -2 °C and the maximum at 20 °C. For the duct temperatures, keep values of 1 to 7°C as a minimum (2°C lower than the product temperature, for seed potatoes stored at 3°C, this is 1°C and 7°C for crisps potato stored at 9°C).
With sufficient renewal, the CO2 content remains below 0.25%. (2,500 ppm). Depending on the variety, high CO2 levels increase the reducing sugar content and leads to a poorer frying colour. It also shortens the dormancy and can lead to black hearts.
Remember that potatoes at 9°C produce up to 30% more CO2 than at 7°C. Adjust the refresh settings accordingly.
• Make sure you have enough refreshment (in the absence of a CO2 sensor: 2 x per day for 10 minutes)
• When using a CO2 sensor, the system automatically controls the fresh air flushes
• Keep refreshing during cold periods
• Pay attention to temperature fluctuations (this promotes sprouting and CO2 production)
• Limit the number of hours of internal ventilation if this is not necessary, dry is dry!
The underwater weight is good in most storages (on average 403 g/5 kg), with some occasional floaters. The solidity of the tubers has remained virtually stable compared to last month, so we can still speak of firm potatoes.
The frying colour has on average barely decreased compared to February and averages 2.1, which is very good (scale 0-6). The proportion of heterogeneous french fries is limited and averages around 3%. We see a slight increase in frying colour in March, for all sprouting suppressants.
In most storage facilities, sprout control was only started in January. Keep checking for sprouts and use a sprouting suppressant if necessary. When using 1.4 Sight, pay attention to the safety period of 30 days.
Source: Omnivent Techniek UK Ltd