The must have tools for this bread recipe are:
1. Kitchen Scale
2. Bread Loaf Pan
3. Large Mixing Bowl
4. Rimmed Baking Sheet or Cast Iron Skillet
(for steam bath in the oven)

Nice to have tools are:
1. Bench Scraper
2. Bread Lame (for scoring the loaf)

Every ingredient matters, this includes the filtered water and sea salt.

When making sourdough bread, since this is an active fermentation recipe, you will want to use the highest quality ingredients possible.

I recommend organic, unbleached and stone-ground flours only.

Bread flour has a higher gluten content than all-purpose.

Use fine sea salt, unrefined Redmond Real Salt, Pink Himalayan or Kosher.

Only use filtered water as tap water will not work well for the fermentation process.

The temperature is also an important ingredient. All of your ingredients should be the same temperature. 73°F - 75°F is ideal.

If you do not have a warm and draft-free area in your kitchen, you can use your oven with the door closed and the oven off.

Turning on your oven light will create an even warmer environment and is great for bulk fermentation and proofing.

The levain is the second sourdough starter you will use to make this bread loaf.

During the colder winter months, use a 1:4:4 or 1:5:5 ratio to build your levain. As colder temperatures slow fermentation, a bigger amount of starter is needed to reach peak in the 10-11 hour time frame.

To a larger glass jar, add 20 grams of mature starter, 40 grams of bread flour, 40 grams of whole wheat (or rye) flour and 80 grams of filtered water.

Mix well until all of the dry bits are fully incorporated then loosely seal with a lid and store it in a draft-free area in your kitchen and away from the sun.

During the warm summer months, use a 1:10:10 ratio to build your levain as it will reach peak much quicker.

To a larger glass jar, add 8 grams of mature starter, 40 grams of bread flour, 40 grams of whole wheat (or rye) flour and 80 grams of filtered water.

Mix well until all of the dry bits are fully incorporated then loosely seal with a lid and store it in a draft-free area in your kitchen and away from the sun.

First, check to see if your levain is ready.

The levain should have grown, show a lot of bubbly activity and appear stringy when using a spatula to scoop it out.

The best test is the float test. Get a small bowl of water and add about 1 teaspoon of the levain. If the levain floats, it is ready* for use.

Get the kitchen scale and a large mixing bowl and add 400 grams of bread flour, 100 grams of all-purpose flour and 10 grams of sea salt.

Mix with your hands.

Next, add 340 grams of filtered water (should be at room temperature) and 130 grams levain.

If you live in a hot and humid climate, I recommend only adding 300-320 grams of filtered water and 100-120 grams of levain.

Using your hand, mix well until all of dry bits have been absorbed.

Dump the dough ball onto your clean work surface and knead for 8-12 minutes.

To knead, use your dominant hand to push the dough with your palm away from you, then grab the dough with your fingers to pull it back.

In the beginning, it will be messy but continue with the kneading process until the dough comes together and creates a smoother dough ball.

Do not add any additional flour during this kneading process. Use your hand or bench scraper to bring the dough back together every minute or so.

Watch the video at the top of this post to see how to properly knead the dough.

To test if the dough has enough gluten development and strength, lightly water or oil your hands, grab a small handful amount of the dough then use your fingers to carefully stretch the dough from the center out.

If the dough tears easily, it is not ready.

If you can see through the thin layer of dough (window pane test), it is ready for bulk fermentation.

Bring the dough ball together then transfer it back into the mixing bowl and cover with plastic wrap.

Allow the dough to bulk ferment in a warm and draft-free area in your kitchen. Cover the bowl with a kitchen towel to keep it away from direct sun-light.

*If your levain is not passing the float test, it either has not reached peak yet or it has already reached peak and is now at its falling stage. Asses your glass jar and if the top of the levain is still domed, it still needs time to reach peak. If that's the case check on it every 10 minutes or so. If you see some falling streak marks on the glass jar, you will need to re-start by creating a new levain. To be able to make bread the same day, create a levain with a 1:1:1 ratio and it should reach peak after 4-5 hours when kept in an environment that is 75°F-80°F.

The dough will bulk ferment for 3-4 hours. The colder the room temperature, the longer it will take to ferment.

During this time, the dough will continue to gain strength and trap carbon dioxide gasses which gives the dough volume and lightness.

This fermentation is the same as the one that occurs in sauerkraut or kimchi!

If the dough has grown, slightly domed at the top and may even have some visible gas bubbles, it is ready for the next step.

Lightly flour your work surface and carefully dump the dough out. Use your lightly floured hands or a bench scraper to loosen the sides of the dough so it releases from the bowl.

Try not to deflate the dough too much as you want to retain as much of those gas bubbles.

Stretch and fold all sides of the dough into the center until you have a tight ball, then turn the dough ball over, seam-side down.

Allow the dough ball to rest for 15-20 minutes.

Using lightly floured hands or a bench scraper, loosen the edges of the dough ball then gently flip it over.

Brush off any excess flour.

To shape the dough into a log shape, stretch the right side of the dough then fold it into the center on the dough, pressing it down so it adheres.

Then stretch the bottom of the dough and fold it into the center of the dough, pressing it down so it adheres.

Repeat the stretch and fold with the left side.

Stretch and roll the top of the dough down into a long tube, similar to rolling a beach towel.

Roll the dough so it's seam-side down.

Place your hands on either side of the loaf with your palms facing the loaf.

Gently push the dough from both sides and slightly cup the bottom edges to seal the bottom and all four sides.

You can lightly grease your loaf tin but it is not necessary.

With lightly floured hands, lift the dough log and place it into your bread loaf pan with the seam-side down.

Lightly flour the top of your loaf then place it inside a large plastic bag (making sure the bag does not touch the top of the dough).

I use a plastic produce bag.

Allow the dough to proof in a warm and draft-free area in your kitchen for 2-3 hours.

Alternatively, you can proof the dough at room temperature for 1-2 hours then move it to the refrigerator and cold proof for 10-12 hours.

Preheat your oven at 450°F for 1 hour.

10-15 minutes before the bread goes in, add a large and rimmed baking sheet or a large cast iron skillet to your bottom rack and fill it up with water about half way.

The water will start to boil gently and create steam in the oven.

I do not recommend using glassware as it may shatter in the oven.

By now, your loaf should have grown and appear light and bubbly.

You can score the loaf with a bread lame or a sharp knife.

This is optional but recommended as a slash in the dough will give it a more even oven spring and rise.

Before you slash the dough, sprinkle a bit of bread flour on top and gently coat and spread it with your hand evenly.

Using a sharp lame or knife, slash one long cut off center.

Lower the heat of the oven to 425°F and add the loaf to the oven.

Bake with the steam bath for 20 minutes.

After 20 minutes, use oven mitts to carefully remove the steam bath from the oven and lower the heat to 420°F.

Rotate the loaf for even baking and bake for another 30 minutes.

Once the bread comes out of the oven, remove it from the loaf pan and allow it to cool on a wire rack for at least 2 hours.

The bread should be completely cool to the touch before slicing.

If you slice in too soon, the crumb will be gummy and the bread will go stale faster.

Allow it to cool in a draft free zone.

Store the bread in a bread basket with a lid or a plastic bag.

You can also slice and freeze the loaf and toast each slice before eating.