Having a deep freeze or extra freezer is great but once it is stocked how do you remember what you put in there? Our freezer is in the basement and when it came time to make grocery lists and menus I did not want to go downstairs to check what we had on hand. Thus, we started to keep an inventory of our deep freezer. I have a truly generic inventory system that is hand written in alphabetical order (thanks to the hubby) and posted to the refrigerator in the kitchen.
However, when I was getting ready to write this post I did a little "research" on home freezer inventory and WOW, there are people out there more organized than me! Hard to believe, I know, but I came across a variety of printable sheets that you could use as your own inventory list. The one on the left and another great one I found is from smartshoppingladies.com.
Depending on where your extra freezer is located there is a system that would work best for your situation. A few ideas that you could use would be to hang an inventory list with the extra freezer, or have a list by each freezer to cross reference the items as you use them. If your tech savvy you could have the inventory list on your cell phone using the notepad or one of the many home maintenance apps and adjust it from wherever you please.
However you choose to keep an inventory of all the "make ahead" meals and groceries you buy for the deep freeze is up to you, but it will definitely save you time and money.