Truly, I am not going to get deep into sourdough bread on this blog. There are dozens of really excellent sites devoted to it and my efforts are very amateur in comparison. If you are a first-timer then the excellent SOURDOUGH LOAF FOR BEGINNERS by Jack Sturgess is a good place to start.
What I would say, though, is that to master sourdough you need to master the hydration for your particular starter. My starter is an organic Goucestershire rye: the heritage goes back over 40 years, traced to a kitchen not far from the Shipton flour mill in Tetbury, which is well known for it’s rye flour. And what I have learned is that, given the limit to my patience with very wet doughs, for this starter the overall hydration needs to be around 66%.
“Hydration?” you ask. Well, to explain let’s take apart Jack’s sourdough beginners recipe mentioned above. First of all, you can see that his starter recipe is a 50/50 water/flour mix: this is pretty standard for sourdough. So the 100g of starter he uses to make the bread is essentially 50g flour and 50g water (plus the yeast of course). One of the main reasons for choosing a figure like 50/50 for your starter is so that it is easier to calibrate your recipes.
Moving on to the bread, his recipe calls for 450g flour and 310g water. When you add in the starter flour these figures become 450+50=500g flour and 310+50=360g water. And so, expressing the water as a percentage of the flour gives us 360 / 500 = 72% hydration. Easy! (Well, easy-ish).
But for my rye starter I find 72% way, way too high: the dough ends up far too wet for my liking, to the extent that in summer when the yeast is very active on warm days, the dough is an unmanageable slop. There are videos around explaining how to handle really wet doughs and, honestly, I have tried. But I have come to the conclusion – after lots of experimentation – that 66% is a much better hydration level for me and for my rye starter. To get there, I reduce the water by 30g to 280g: do the maths and you’ll see this is indeed 66% hydration*.
I have tried going below this hydration level and I find that getting all the flour into the wet during initial mixing is very tricky – so, for me, 66% it is.
What I really want to stress, though, is that for you, working with your (different) starter, this figure may be too low – or too high. Your call. You will need to experiment to find out and, if you are like me, have some epic failures along the way. But when you have found a level of hydration you like, it is always a good starting point for adapting a new recipe.