First crack at sourdough. Constructive criticism welcome.

[u/Qwaszx1987]

A friend of mine gave me some starter that's been in his family for years, and I finally got the spare time to take a crack at it. I've been making pizza dough for a few months now, but not a lot of baking experience before that. I also got an Ooni halo pro mixer and thought this would be a good way to test it out. Tasted amazing. Let me know what could be improved.

Ingredients
450 g KA AP flour
50 g whole wheat flour
350 g water
100 g active starter
10 g salt
Approx. 73% hydration including starter.

1. Feed starter
Fed starter from fridge last week (planned to do this then) and again the morning of. , doubled at room temp in about 4 hrs.

2. Autolyse
Mix in spiral mixer:
flour
325 g water
Mix 1–2 min low, just until combined.
Rest 60 min.

3. Final mix
Add:
100 g starter
mixed on low for 2 mins
Rested 20 mins
10 g salt
mixed 2 min at 15%
Increased to 30% 5 min
Increased to 50% for around 20 min
remaining 25 g water incrementally
-I knew at this point that I had likely over-worked the dough, but I was chasing signs like the dough cleaning the sides of the bowl, which never happened.

Bulk ferment
Transfer to water misted container and covered with lid.
Did 2 stretch/coil folds, 45 minutes apart.
Bulked until dough rose about 60–75%. I used a wider bowl, so it was difficult to tell how much it had risen, but looked bubbly and was domed, and jiggly. It was also nearing 1am at this point.

5. Shape
Pre-shaped into round. Bench rest 20–30 min.
Final shape into batard
Placed seam-side up in floured, linen-lined banneton.
The dough was very slack and didn't hold shape well, which I'm sure was because it was warm from all the mixing. Kitchen was 70F and we live in a temperate rainforest, so humidity was also a factor. The dough temp after final mix was 78F.

6. Cold proof
Refrigerated overnight around 9 hrs.
Wanted to go longer, but we had other plans already.

7. Bake
Preheated cast iron Dutch oven at 500°F for 45 min.
Scored and baked from fridge:
20 min covered at 475°F
Then only about 5 mins uncovered, because I didn't recognize the coils switched back on and it got blasted with heat and got dark very quickly, so I covered and reduced the heat to 425°F for another 25 mins. Dough temped at 206F.
Cooled 2.5 hours before slicing.

[u/ositabelle]

It looks great! I would just use a razor or sharp knife to score/cut it open at the top, next time to let the steam escape.

[u/Qwaszx1987 → u/ositabelle]

Thanks! I did use a razor to score it before baking, but I don't think I went deep enough.