The green walnut is the unripe walnut fruit (J. regia) harvested before St John’s Day on 24 June. The walnut shell contained in the fruit has not yet become woody – but it already contains plenty of indigestible tannins. In order to remove these, the fruit or its outer skin must be punctured a few times and then watered for several weeks or months. During this process, the tanning agents colour the fruits and the water black-brown, which must be exchanged regularly. Finally, the treated fruits are cooked in syrup and spices for a long time, which can be followed by another long storage period up to several years. The ready green (or now black) walnuts can be cut into thin slices and served with sweet desserts or spicy dishes. A real speciality! And if you are afraid of the effort, you can fortunately buy them ready to eat.

Instead of macerating in water, you can also macerate in alcohol for several weeks to obtain a black liqueur. In Italy the Nocino is produced in this way, where the green walnuts are harvested punctually in the night to St John’s Day and infused with grappa, coffee beans and various spices.

• Edible Fruits (unripe)
• Type of Fruit Nut
• Culinary Group Wild fruits
• Taste astringent (if untreated)
• Trivial Names Johanninuss, Johannisnuss, Grüne Walnuss, Green Walnut
• Size (single fruit) 4 cm
• Taxonomy Juglandaceae (Walnut family) Juglans regia
• Origin Near East, Mediterraneum (Map)
• Locality Gathered, Park in Frankfurt 2015