I am beyond happy with this! It turned out better than all previous loaves, though I'm unsure why... My 'intuitive' approach is definitely working - sticking to one recipe and just tweaking things step by step rather than going for a completely different method that's worked for someone else.
250g white flour, 250g wholegrain wheat flour.
Starter: I used it straight from the fridge, but I'd fed it a couple of days before with white flour instead of wholemeal. Maybe that made a difference?
In the morning, did 1 hour autolyse, then mixed in starter & salt.
4 stretch & folds over 2 hours, then a bulk ferment at room temp for about 5-6 hours with another stretch and fold in between.
Proofed in a glass bowl, covered with a plastic bag, overnight in fridge for about 16 hours.
Slashed the top which was difficult due to crap knife and very sticky dough.
Baked in dutch oven at ~230c for 20 mins covered, 30 mins uncovered. Let cool for 1 hour.
Result: Really nice, EVEN crumb without the heaviness/density of previous attempts. This must be because of a longer proof in the fridge, and possibly the activity of sourdough starter.
The sides look kind of ugly because of the baking paper I use. My makeshift dutch oven is a little too small so it causes creases in the sides.