how long will preserved lemons keep once opened
For longer storage, process 1/4 or 1/2-pint jars of lemon curd in a boiling water bath for 15 minutes. Once processed, jars of lemon curd will keep in the refrigerator for 3 months until they are opened (after opening, they will only last 1 - 2 weeks).The surface of curd in sealed jars may darken slightly if kept longer than a month, but that is an esthetic concern, not a health hazard.nce processed, jars of lemon curd will keep in the refrigerator for 3 months until they are opened (after opening, they will only last 1 - 2 weeks).