Yacón (Smallanthus sonchifolius) aka Peruvian ground apple, Bolivian sunroot
Sweet-tasting tuber makes ‘no-sugar’ syrup suitable for diabetics
Here’s an interesting tuber with the texture of water chestnuts and a sweet taste of pear with a hint of watermelon! Yacón is deliciously juicy, especially when freshly lifted and eaten raw – the word ‘yacón’ apparently means ‘water root’ in the Inca language and this turns out to be a very apt description. An exciting feature of this tuber which looks quite like a sweet potato, is that the liquid content from the tubers can be extracted using a juicer (or food processor – see Culinary Uses) and made into a super sweet syrup which can be used as a substitute for sugar, much like honey or maple syrup. And the best thing about the syrup, is that it’s virtually calorie-free! Yacón contains an indigestible sugar called inulin which means that yacón – the tubers AND the sweetening syrup – are suitable for diabetics.
How to make ‘sugar-free’ yacón syrup
Wash tubers thoroughly and whizz them in a food processor to make a pulp. Then boil the pulp in a large pan, using a cooking thermometer to keep the temperature at approximately 103°C, to form a dark brown syrup. Just four plants should provide the 12 kgs of tubers required to produce 1 litre of syrup.
Culinary uses of Yacón
Fresh tubers can just be washed – no need to peel them if they are just out of the ground – and sliced to eat raw as a snack, in salads or added to stir fries. It should be noted that the flesh will tend to discolour – like apples and potatoes – so sprinkling with a little lemon juice (or apple juice) will slow this process down. When using yacón in salads, it’s best to toss it in lemon juice (or in lemon juice diluted with water) and add it just before dressing and serving.
Don’t throw away the foliage from your yacón! A few fresh leaves from each plant can be cut during the summer and autumn, tied together and left to dry naturally in the kitchen or airing cupboard. Once dry, crumble them into boiling water to make a delicious ‘green tea’. Crumbled leaves will keep fresh for many months in an airtight container.
Yacón will absorb sauces, dressings and condiments so it can be used as a delicious and different ingredient in a variety of sweet and savoury salads. Try it with grated carrots and a grainy mustard vinaigrette as a colourful salad. Or chopped and added to a colourful fruit salad of pineapple, mango and pomegranate. Yacón can also be roasted along with other root vegetables, tossed in olive oil, sprinkled with sprigs of rosemary or simply steamed. The possibilities are endless.
Yacón is easy to grow in most soils, although deeper soils will provide a heavier yield of larger tubers. Plants will greatly appreciate the addition of compost and/or well-rotted manure each autumn. The height of the plants makes them ideal companion plants for spinach, French beans, courgettes and radish plants to utilise space in between plants and to provide dappled shade.
Grow yacón from ‘buds’ (also known as ‘caudices’) which should be potted up individually from February to early April in moist compost with the growing point upwards. Keep at about 18°C until shoots appear. Plant them out when the risk of frost has passed and once plants are approx. 7-10cm tall to ensure they establish more reliably. Position the plants in a sheltered, sunny spot, at the same time as you would plant out your courgettes. Plants are tall – up to 6ft (180cm) – so allow approx. 30in x 30in (75cm x 75cm) for optimum yields. Small flowers are produced in the summer and tubers are formed in the autumn. Frosts will tend to tinge the foliage, but a heavy frost will usually wither or blacken the leaves and it is then time to lift the tubers, usually during November.
Using a long fork, carefully lift the tubers as they tend to bury quite deeply in the soil, and will form a clump similar to a dahlia. Carefully break off the tubers. Any damaged tubers should be used promptly or made into syrup as they will rot in storage. Only undamaged tubers will store.
An average plant will yield 3.5-4 kgs of tubers.
Tubers store extremely well in paper or hessian sacks in a cool dry place in the shed or garage, but they need to be kept frost free. They often sweeten over time. Keep a couple of yacón tubers in the fruit bowl where they will ‘warm up’ and sweeten further before use.
Stored tubers will form a thicker skin, which turns a darker brown colour and will need peeling, as it becomes more bitter over time.
Yacon buds are available on the Thompson & Morgan website. Click here for more details.
Recipe suggestions from Mark Diacono at guardian.co.uk