This is the standard rye sour I use for my German - inspired rye breads
Ferment for 14 hours at 28C
If you have a different temperature, ferment longer.
Alternatively you can add more starter (up to 20%)
If your kitchen is hotter, you can use less mature starter (5%) or add some of the bread's salt.
I keep my starter in the fridge and refresh it once or twice before baking a batch (which happens once a week).
To start this rye sour begin with small quantities, and add abit of honey at the beginning:
1. Feed: 10 g rye + 10 g water + 1/2 tsp honey
2. Feed after 12 hours: add to feed 1: 10 g rye + 10 g water
3. Feed after further 12 hours: Add to feed 2: 20g rye + 20g water
You get the idea. Proceed like this for 3 to 5 days, and yo should have something that is alive.
Now you can switch to a slower feeding cycle and less mature starter, e.g, the proposed ratios above once a day, until you are happy with the smell and taste.
You are ready to bake now.
This starter looses about 10% of its weight during fermentation