Michael, at those temps (20c = 68f, 23-25c = 73-77f), I'm pretty sure you will get a sour loaf if you let the dough go to 24hours.
So yes, it's a good idea to watch the dough and see but this is how we learn. From experimenting and trial and error.
As an example, here is a loaf of bread I made using 3% active ischia starter and a room temp (75F = 24c)ferment of 23h. It was sour tasting, but remember that ischia will be a stronger tasting starter than your hybrid starters. So at 3% using your hybrid starters, 24h will give a much less sour loaf. At 8% starter and 24h, at your current temp 20-25c, you will likely have a sour loaf.
Reply #78
http://www.pizzamaking.com/forum/index.php/topic,12538.60.htmlSo if the dough looks ready before the 24h is up, then go ahead and bake it.
The other tricky part is gluten development (relative to hydration ratio). Here's something important to think about. If you don't have the right amount or enough gluten built into the dough, it will look like it's not rising much or that it's taking a long time to rise. You will you naturally wait for the dough to rise meanwhile it is reaching overfermentation and you wouldn't know it. Maybe not overfermentation but it will be further along in it's fermenation that it seems IF you are looking just at the volume of rise as an indicator. For an example of this if you make 2 loaves with the same amount of starter and build gluten in one and not the other. The one that has gluten built into it will look ready to bake sooner b/c it is rising and expanding. While the other will be ready at the same time but will not rise nearly as much. Imagine if you didn't have the first loaf for comparison, you might let the 2nd loaf rise long to try to get a bigger volume. But if you did that you would end up with a more sour loaf b/c you let it ferment too long. Does that make sense?
This is why it is also important to know your starters and how they behave. Also important to taste the starters for level of acidity. Also important to smell the dough as it is proofing especially near the end. Learn to smell what a Sourdough loaf will smell like.
Michael, at 8% active starter (depending on the specific starter, hydration ratio, and strength of flour used) and your current fermentation temp, I am estimating your dough should be ready to bake in the 12-15 hour range.
Let me know how the bread turns out.
By the way, your pizzas are looking good.
Chau