Combine the yeast and the warm water in a large bowl. If using active dry or fresh yeast, add the sugar as well, then let the mixture sit for a bit (5-10 mins) until it starts to bubble up then move on to step 2. If using instant yeast, you can move on to the next step without waiting.
Add the sugar (unless you already added it to the active dry/fresh yeast), salt, whole wheat flour, and bread (or all purpose) flour to the water and yeast mixture.
Stir until you have a scraggly dough and have saturated most of the dry spots. If the dough is feeling wet at this point (if it saturated the flour quickly and is very sticky), be sure to add a few more tablespoons of flour! Alternatively, if the dough is very dry, add a tiny bit more water!
Once the dough is ready, cover the bowl and let this rise somewhere warm for 30 minutes.
After 30 minutes, complete your first stretch and fold. Instead of kneading this bread, you are just going to do what is called a stretch and fold. Basically, with slightly damp hands (just run them under water briefly) you will pull up the dough by placing your hands under the left and right side of the dough and stretching it up and out along the edge of the bowl farthest from you. See the process photo!
Then, fold the dough over itself towards you, pressing it down towards the edge of the bowl closest to you. Rotate the bowl 90 degrees (either way), and repeat three more times, rotating each time (for a total of four folds). See this great blog post from The Clever Carrot for more help with this technique! Once you have completed this first set of stretching and folding, let the dough rise again (covered) for another 30 minutes. After the second 30 minutes, complete the second stretch and fold by repeating the same steps above. Let the dough rise again (covered) for 15 more minutes.
Now you are going to pre-shape the dough. Sprinkle some flour onto a countertop or work surface and tip out your dough onto the surface.
Roughly shape your dough into a ball. Then, pull the sides into the middle gently, pinching them together at the top like you were shaping a very large bread roll.
Flip the whole loaf over again on the surface so the seam is facing down. Cover with a towel or cling film and let this rise for another 10 minutes.
While the dough is resting, cut 4 long pieces of butcher's twine. Add a few tablespoons of neutral oil to a plate and put the pieces of twine into the oil to soak.
After 10 minutes, you are going to complete the final shaping of the loaf. Flip the loaf over again so that the seam is facing you. Repeat what you did before - pulling in the sides and pinching them together - but this time, you can be a bit less gentle. You really want to make sure the loaf doesn't spread and you create the necessary surface tension on the dough's surface to get a good rise in the oven.
Place the oil soaked strings on a table or on a parchment lined baking sheet (try to squeeze off any excess oil as well) - place one string down first, the next at a forty five degree angle to the first, and the third at another forty five degree angle, and again with the last. You should be left with 8 equal sized sections.
Flip the loaf over again so the seam is facing down; brush the top with flour, dusting off any excess, and then transfer on top of the twine, right in the center.
Tie the pieces of twine together across the loaf (tie the opposite ends of the strings together). It should create eight even sized sections on the loaf.
Cut off any excess string.
Now, transfer the loaf to a parchment lined baking sheet and put the loaf into the fridge to rise for 20 minutes, covered (this makes it easier to score and helps prevent over proofing, but feel free to leave them at room temperature if your fridge doesn't have space!).
While the dough is in the fridge, set your oven to 450 F (230 C) and place a metal or cast iron pan/tray on the bottom rack of the oven to heat up and start boiling some water (1-2 cups) on the stove or in a kettle. Make sure you have a second rack in the oven set above the tray. If you are using a Dutch oven, you don't need to do this, but put your Dutch oven with the lid on into the oven to preheat! Don't forget this step as putting a cold Dutch oven directly into a hot oven could cause it to crack.
After 20 minutes, remove the loaf from the fridge.
Using a very sharp knife or razor blade, score the bread once along each of the eight sections. Try your best to score at a 45-degree angle or less about 1 inch into the loaves. Read more about scoring here. If using a Dutch oven, simply drop the loaf (on the parchment paper it's already sitting on) into the preheated (very hot!) Dutch oven, add the lid, and place into the oven. Bake for about 20 minutes with the lid on, then remove the lid for 5-10 minutes until the bread has formed a beautiful dark crust.
If using a baking sheet and a metal pan/tray at the bottom of the oven, follow these instructions! While wearing oven mitts and being very careful, pour 1-2 cups of the boiling water into the pan in the bottom of the oven. Quickly place the baking sheet with the loaf into the oven on the rack above the metal tray and immediately close it. Bake for 25 minutes or until it has formed a dark crust.
Once the bread has formed a lovely dark crust and sounds hollow when you tap it, remove from the oven and transfer to a cooling rack.
After a few minutes, cut the string and remove it from the loaf.
Let the bread cool for at least 30 or so minutes to an hour before slicing. Enjoy!