Fresh out of the ground yacon is very much like a baking potato to look at. However its flavour is a little strange for what you might expect from an underground tuber – it’s like a sweet cross between early apples, watermelon and very mild celery, with a touch of pear. Mildly flavoured raw when first dug, it’s the texture as much as the taste which sets yacon apart. The tubers have that fine texture of water chestnuts. They don’t quite collapse as such – they’ve more resistance than that – but, like a very fine sorbet, they do sort of give in.
Yacon is also refreshingly juicy. “Yacon” means “water root” in the Inca language and its tubers were historically highly valued as a wild source of thirst-quenching refreshment for travellers. The liquid can also be drawn off and concentrated to produce yacon syrup. As with Jerusalem artichokes, yacon tubers are rich in an indigestible sugar – inulin – meaning that the syrup they form has all the sweetness of honey or other plant-derived sweeteners like maple syrup, but without the calories.
Yacon also benefits the bacteria in the intestinal tract and colon that boost the immune system and aid digestion. This potential as a dietary aid and as a source of sweetness for diabetics has led to yacon being grown more widely, especially in the USA.
Yacon is a perennial plant, so once you have planted it, so long as you look after it, you will have it forever.
Yacon is pleasingly easy to grow in most soils where there is reasonable rainfall and moderate heat. The plants do require a long season to grow – forming their tubers in autumn – but anywhere that parsnips and Jerusalem artichokes thrive will suit yacon perfectly well.
Yacon can be slow to get growing in spring but quickly puts on lush, leafy growth through the summer to a height of 2m, occasionally a little more once established. It flowers some years towards autumn, but it’s what’s happening under the surface that’s of most interest.