[FunkyDuckling]

Sourdough doesn't need to be sour!

I think the main factor for this is how "mature" your starter is.

After feeding your starter it will expand, then collapse, then grow more sour. I generally time it so that my bread isn't as sour.

If I am baking soon -- larger leftover starter and smaller feed. if I am baking tomorrow -- tablespoon or so of starter with bigger feed to get my leaven.

[giraffe_lady]

As I understand it it's mostly the balance between lactic acid and acetic acid bacteria. There are different ways you can encourage the balance to shift one way or the other and they have different growth patterns under different conditions so timing your bake around it can work but may have other compromises. The yeasts are important too and are on yet another schedule.