Wild plum jam
We usually suggest against doubling the recipe. During boiling some of the liquid is steamed off and with a double batch, there is less surface area, so the length of the boil may not be enough to reduce the entire amount as needed to allow it to gel or thicken as much as you would like. If the jam boils much longer it will taste very cooked. Jams are usually made in small batches so they heat through and cook quickly to preserve as much fresh fruit flavor as possible. If you double the batch, it is unpredictable but not unsafe.