Sourdough keeps really well. By its very nature it is generally a firm bread, and best cut when it is at room temperature (bread continues to “cook” when taken out of the oven and should be allowed to cool, so if you cut bread when it is still hot it will lose valuable moisture and make it a dry loaf).
I make six loaves every week which I share with my family. Three go out to family members, and the rest is kept for our own use. Once I’ve baked I will keep a fresh loaf out for us to consume, and the other two go into individual freezer bags and popped into the freezer for later in the week.
The fresh loaf I keep out for us to consume is kept in a freezer bag in the pantry which I loosely close up. As we near the end of that loaf, which takes roughly three days, I take another loaf out of the freezer the night before to defrost overnight ready for the morning. This loaf is also kept in the same freezer bag I used when I put it into the freezer until it is used up. As that nears its end the final loaf comes out. This is the routine we have used for years and works really well for us.
NB: If you prefer you can keep your fresh bread in a cotton or calico bag, but a freezer bag is what I use. I am being honest with you here as I know many people would prefer I said I keep them in a bread bag, but I found the loaf dried out more in a bread bag, and I’ve never had that problem with keeping them in a freezer bag. It also makes handling them particularly easy in a busy household, which helps all of us here enormously.
As I try to use up every part of the bread, if I happen to have small bits nearing the end of the loaves (I love the crusts, but not everyone does), I make breadcrumbs out of them, which I store in a snap lock bag in the freezer for easy access. I am then able to use them as needed for a recipe by taking out just what I need and returning the rest to the freezer (the breadcrumbs don’t freeze in a “block” so it is easy to remove just what you need).
If you are using your Thermomix to make the breadcrumbs, add up to 300g sourdough, cut into 3 to 4 cm cubes, to the TM bowl and mill 10 seconds / speed 6. Place into a snap lock bag or other container and place into the freezer.