Most nuts have a fat content of between 54.2 and 72.1 percent. Freshly shelled nuts have the best flavor, but shelled canned or bagged varieties are excellent and a lot more convenient. All nuts are prone to rancidity, but higher fat nuts such as walnuts, pecans, and macadamia nuts are more prone to spoilage than others. Always taste nuts before using them. Rancidity will ruin the flavor of a dessert, and it’s often not possible to detect just by smelling. Nuts keep well for several years if stored airtight in the freezer. I use either plastic reclosable freezer bags, expelling all the excess air, or glass canning jars, filling the empty headspace with wadded up plastic wrap before freezing.