Mix your leaven, water, flour and salt together with a wooden spoon, your hand, or my preference, a danish dough whisk. Mix just until there is no dry parts.
Let sit 20-30 minutes, then knead it together to make a uniform dough.
Over the next 2-3 hours, find 2-3 more times where you will knead the dough 10 times. This is called stretching and folding, but essentially, its just gentle kneading.
At this point, you can leave your dough on the counter to rise until double OR put it in the fridge overnight if your house is very warm. Timeline is going to depend on temperature of your dough and your house.
When your dough is doubled, its time to shape it! Dump the dough onto a counter (it shouldnt need flour) and divide it in two. You CAN make one big loaf, baking a few minutes longer, but I like 2 medium sized loaves.
You now 'pre shape it'. Press the dough out with your hands, to make it a rectangle roughly the size of your two hands side by side. Fold it like a letter in thirds, put it seam side down on the counter and let it rest 10 minutes.
This part is yours to decide, and will help you decide how to shape it. - if you want to bake it free form in a dutch oven, you will flour the dough and put it in a banneton OR some other basket/bowl to rest. If you want
After the rest, flip it seam side up again, if you're doing a loaf pan or oval banneton, press it into a rectangle the same size again, and then this part is a little tricky to explain...but it you fold one long side in to make it a triangle, then roll the point of the triangle in towards the wide end, it should make a nice tight loaf for you.
If you're using a round banneton, you will do the rectangle like above, but shape a little different, fold it like a letter in third to make it a rectangle, then fold the long ends in on top so its kind of a square. Flip it seam side down, and kinda preen the loaf a bit to make it more round. It's forgiving and doesnt need to be perfect.
Cover the shaped loaves with a damp towel or in a plastic bag. Let rise in the fridge overnight (or on counter if its chilly) or just on the counter for a few hours. It doesnt need to fully double, but just more like 1.5 its size.
Preheat your oven to 500F. If you are using a dutch oven, pop it in the oven to preheat as well.
When your oven is hot, uncover the loaves. For the loaf pans, simply slash the tops with a sharp knife to allow expansion.
For bannetons, I use a small piece of parchment, put it on top of the loaf, and then gently turn it onto the counter so the rounded side is up. Slash the tops. One long lengthwise slash and the loaf will expand out width wise. Shorter slashs encourage the dough to rise up not out more. Its all about preference in looks.
Put your loaf pan in the oven to bake OR take the dutch oven out, gently put your loaf on parchment in, lid back on, and back into the oven.
Lower the temp to 450F. Bake for 20 minutes. Flip loaf pans around or take the lid off the dutch oven.
Bake another 15-20 minutes, until the loaves register 180F-190F with an instant read thermometer. I feel this is the best way to know your bread is done.
Your bread needs to fully cool before baking in order to not be gummy, this is the nature of 100% fresh ground wheat bread.
I like to wrap it in a cotton or linen tea towel OR I have a lovely small wool blanket. Basically, wrap it in some 100% natural fibre piece of fabric/small towel/blanket, which softens the crust as it cools.
Now once its cool, enjoy!! This bread lasts for dayssss tasting so good when its refreshed in the toaster or oven. We cant get enough of it!