History
Just like regular potatoes, their origins lie in Southern America. The Inca were already cultivating sweet potatoes 800 year after Christ. It was probably Columbus who brought the first sweet potatoes to Europe.
Sweet potatoes are not potatoes
Unlike regular potatoes, which are tubers, sweet potatoes are considered to be root vegetables. The root, however, is described as a tuberous root. Both sweet and regular potatoes grow under the soil, but they are very different when it comes to density, taste and nutrition.
Sweet potatoes are in the plant family Convolvulaceae (morning glory) Ipomoea batatas potato, Solanaceae (nightshade) S. tuberosum.
At first glance, the exterior of the sweet potato seems to be the same as a normal potato; on closer inspection however, the skin colour and the shape are very different.
In terms of flavour, sweet potatoes taste more like carrots. The flavour is very sweet, as the name suggests. The ‘brix’ level (the level of sweetness) will vary between the different varieties. This depends on the place where they were grown and the variety which was used. It is clear, however, that we cannot really compare sweet potatoes with regular potatoes.
Another difference between the normal and the sweet potato is the nutritional value.
More about the nutritional value of the sweet potato can be read here.
How do they grow
Nowadays, sweet potatoes are cultivated in America, Asia and New Zealand. China is the world’s largest producer of sweet potatoes; the USA, however, is the most professional grower. Most sweet potatoes are grown in the State of North Carolina, however other states such as California, Louisiana and Mississippi also grow the crop.
It is very hard to grow sweet potatoes in Europe. The sweet potato is a tropical vegetable which means it needs a long warm season of 110 days with temperatures of at least 30 degrees Celsius. The nights must also be fairly warm (above 20 degrees Celsius). And of course, just like every other crop, it needs enough water.
In May the small seedlings are planted out close to each other in the fields. Later in the summer, when the seedlings have grown into small plants, they are replanted in the fields and in September/October the sweet potatoes are harvested. Most of these harvesting activities have to be done by hand.
On average, an American grower harvests 15 to 20 tons per hectare, much less than a regular potato grower in Europe.
After the harvest the farmer stores the fresh crop in wooden crates in cold, well ventilated dry and dark storage barns, where the sweet potato will stay in good condition for 12 months. Sweet potatoes are available the whole year round.
How to store sweet potatoes at home.
The best advice is to buy fresh potatoes at the supermarket or greengrocer. They can be stored outside the refrigerator in a dark, cool, well ventilated place, like normal potatoes. You will then be able to keep the sweet potatoes for up to two weeks.
