The need to preserve food has existed as long as we have, more or less – as soon as our ancestors picked, dug up or caught something for food, there existed an immediate need to preserve it. Ancient civilisations figured out pretty quickly that food could be dehydrated to stop it spoiling, but the discovery that salt could be used to preserve fresh ingredients was undoubtedly a landmark moment for humanity and how we eat. Seasonality and freshness is especially in vogue at the moment, but the work being done at pioneering restaurants like Noma in Copenhagen shows that even today we are still learning about the many possibilities offered by the magic of salt and osmosis.
Like many pickled and preserved foodstuffs, lemons were originally preserved so that they could be eaten outside of their season. Lemons have been a workhorse of Mediterranean and north African cuisine for centuries, but they can only be harvested for six months of the year at the very most – Amalfi and Sorrento lemons, for example, are generally at their best between May and October. As early as the twelfth and thirteenth centuries, literary evidence from north Africa suggests that lemons were being cured and preserved using salt – indeed, a twelfth century medical treatise by Egyptian doctor Ibn Jumay actually lists a recipe for preserving lemons, one that is remarkably similar to modern day techniques. He promoted preserved lemon as a cure for various ailments, and he may well have been onto something – the bacteria developed during the fermentation process are extremely good for your digestive system, but lemons would later be used as a cure for scurvy thanks to their rich vitamin C content.