By curing in a brine and sun-drying, green walnuts become something akin to fleshy, tart-flavored olives. Be sure to use walnuts harvested early enough that they are easy to cut through, otherwise the inner shell will not be edible.

Are green walnuts poisonous?

The leaves and the green shells of the fruits contain a big amount of tannins, which can cause intoxications in people with more sensitive stomachs. Equally the fruit or the oil of the fruit, if it is in contact with the air, becomes rancid and it is toxic.

How do you ripen green walnuts?

The walnuts can be air-dried, by spreading in a single layer in a sunny location or they can also be placed in a mesh bag, like an onion sack, and hung up to dry. This natural drying process may take one to several weeks. You can also dry nuts in the oven. This process will take several days.