Oca (Oxalis tuberosa) is a perennial herbaceous plant, related to our native Oxalis, but with larger edible tubers. It was introduced to Europe in 1830 as its high carbohydrate levels gave it the potential to compete with the potato as a root vegetable.
Though we grow Oca for the edible tubers here at Gravetye, the leaves can also be used as leaf vegetables and it has been suggested to use the stems in a similar fashion to rhubarb. It is the second most heavily cultivated crop in the Andes, where it is part of the rural stable diet due to its high nutritional value. The tubers usually have a tangy flavour, as it is from the Oxalidaceae family, but flavour can be highly variable and changes with cooking. In Mexico the tubers are eaten raw with hot pepper, salt and lemon. The texture of the tubers changes drastically if it is cooked, becoming either starchy or mealy when fully prepared. It has an extremely high carbohydrate concentration, contains potassium, vitamin B6 and beta carotene.
Our Oca crop was covered with horticultural fleece with the first frosts and have been in the ground until this week when they were all lifted, cleaned and stored, ready for the kitchen to use. The tubers are slightly tender and we could already see signs of frost damage on some of them. The main bulk of the crop has been successfully harvested, however, and before long they may find their way to the guest’s dinner plates, in culinary combinations we can only dream of.