I didn’t want to invest in small mason jars until I knew whether I liked the egg bites enough to justify the place they will take up in an already small kitchen. . I found a post somewhere that suggested your put your egg mixture into a silicone muffin pan, then pop it into the freezer for 2 hours. Remove, and then seal individually in plastic bag of your choice. Keep frozen till ready to put in the water bath. I tried it, and they do keep their shape fairly well. I tried putting 2 in one bag, and it was pretty hard to keep them entirely separate from each other while vacuum sealing with the food saver, but not impossible. I may get better at it with practice.