I had 2 kg of rye sourdough discard to use up, so I doubled the formula from The Bread Code Bread Code Video - Sourdough Discard Loaf. There's a link to text of the formula in the descriptions of the photos:
I've made this discard bread a few times. If you're using older discard with no oomph left, the result is a very dense loaf that has to be sliced thin and eaten open face. But it really packs a deep rich rye flavor, especially if you substitute rye for the whole wheat in the formula (I used coarse rye/pumpernickel which is ideal for this bread).
I asked Google Gemini AI for suggestions about the kinds of seed to use. Along with suggesting proportions for a blend of caraway, sesame, and crushed coriander, it suggested using the full 5 hr max proofing time, even though there was no expansion to be had. The long proof would deepen the rye flavor, it said. And wow, it was right. Even with as tight a crumb as can be, sliced as thin as I could and topped with some smoked seafood, it transported me to the Baltics.
It's easy to make and a great way to use discard. But give it a good long proof for flavor.