Providing potato cold storage conditions is very important in terms of providing quality products to the market. Potato is the most demanded product in cold storage. Its nutritive value and long-term storage are factors in this.
Potatoes are made in large crates in cold storage or in silo-shaped containers up to 6 m high by giving cold air from the bottom. Approximately 600 kg of potatoes can be placed in 1 m3 volume. Potato storage is done in 4 separate stages.
Healing
Potatoes are kept for 10-12 days in cold warehouses with 90% humidity between 15-18 degrees. In this way, the wounds formed during the period until the harvest and transport to the warehouse heal and the crusts thicken and harden. This recovery reduces water loss. When the water loss in potatoes exceeds 8%, wrinkling occurs. During the treatment period, the air flow rate in the tank should be high. In this way, the top layer of the stacks is prevented from getting wet. Again in this period, the CO2 rate should not exceed 0.5%.
Cooling
The temperature of the potatoes, whose healing process is completed, is gradually reduced to 6-8 degrees in 12-15 days in the cold storage. At this stage, the air velocity is reduced and the ambient humidity is kept between 90-95%.
Cold Storage
At this stage, the temperature of the cold storage is between 6-8 degrees and the humidity of the storage is 90-95%, and the storage period in the cold storage can be up to 6-8 months, depending on the type of potatoes. At this stage, the temperature of the cold storage should not be lower than 6 degrees. The decrease in temperature causes the sweetness of the potatoes.
Preparation for Market
At the end of the cold storage period, potatoes begin to release 2 times more carbon dioxide, heat and steam compared to the previous stage. In this process, the air speed of the potato cold storage is increased, and the amount of fresh air taken into the warehouse increases. Warehouse temperature is gradually increased above 10 degrees and ready to be marketed
To plan a potato store, our free cold room heat load calculator includes potatoes, and our industrial cold rooms are built to your room size and temperature.
Potato Storage Stages at a Glance
| Stage | Temperature | Humidity | Duration |
|---|---|---|---|
| Curing (healing) | 15–18 °C | 90 % | 10–12 days |
| Cooling down | Lowered step by step to 6–8 °C | 90–95 % | 12–15 days |
| Storage | 6–8 °C, not below 6 °C for table potatoes | 90–95 % | Up to 6–8 months, by variety |
| Preparation for market | Raised step by step above 10 °C | – | Until dispatch |
Storage Temperature by Use
The right storage temperature depends on what the potatoes will be used for. These are typical values; Values from the product data of our cold room calculator, based on USDA Agriculture Handbook 66, UC Davis, FAO and GCCA sources.
| Potatoes for | Temperature | Humidity | Storage life |
|---|---|---|---|
| Table (ware) use | 7–10 °C | 95–99 % | 5–10 months for late-crop, cured potatoes |
| Seed | 4–5 °C | 95–99 % | Until planting |
| French fries | 10–15 °C | 95–99 % | By variety |
| Chips (crisps) | 15–20 °C | 95–99 % | By variety |
| Early (new) potatoes | 10–15 °C | 90–95 % | 10–14 days |
Potatoes for frying are kept warmer because at low temperatures starch turns into sugar, which darkens fries and chips.
Planning a Potato Cold Store
- Capacity: about 600 kg of potatoes fit in 1 m³, in crates or in bulk up to 6 m high with cold air supplied from below.
- Air and ventilation: a high airflow during curing keeps the top layer dry, CO₂ should stay below 0.5 %, and fresh air is let in again before marketing.
- Humidity: 90–95 % limits water loss; above 8 % water loss the tubers start to wrinkle.
- Building: insulated sandwich panels and refrigeration sized for the summer heat at your site, see high ambient condensing units.
Our cold room calculator includes potatoes and gives the cooling load of your store; we build industrial cold rooms to your size and temperature.
Frequently Asked Questions
What is the best temperature for storing potatoes?
It depends on the use: 7–10 °C for table potatoes, 4–5 °C for seed potatoes and warmer, 10–20 °C, for potatoes that will be fried.
Why do potatoes turn sweet in cold storage?
Below about 6 °C part of the starch turns into sugar. The potatoes taste sweet and fry darker, so table potatoes should not be stored colder than 6 °C.
How long can potatoes be stored?
Late-crop, cured potatoes keep 5–10 months under the right conditions; early potatoes only 10–14 days.
