Ingredients
100g active starter
500g bread flour
320-375g room temperature water
7-11g salt
Method and timings
Step 1: Around 6-12 hours before you want to start
Feed your starter. Add 6g starter to 60g flour and 60g water. Mix together and leave on kitchen counter until it has doubled in size and is bubbly and active. Once it's active, you generally have a 2-6 hour window to use it but this will be shorter in warm weather and longer in cold weather.
Tip: A 1:10:10 ratio of starter:flour:water as specified above takes around 10-12 hours to double and get properly active (depending on ambient temperature). You can make this shorter by increasing the ratio of starter to flour and water, or by putting it in a warmer place to develop. Play around with this option to suit your schedule.
Step 2: Getting started (duration: 30 mins)
Once your starter is active, gently mix 100g of it into 320g room temperature water, then add 500g flour and the salt and mix to a rough dough.
If the dough is very dry, add more water in 10g increments, but don't worry about getting it absolutely right at this stage as you can easily incorporate water later by spraying it on the dough.
Tip: it's much easier to manage a lower-hydration dough, so start with 320g water (68% hydration) until you get more confident in your baking. You can then move to 75-85% hydration doughs. Calculate hydration
You can experiment with different mixes of flour. An all-white loaf is normally easiest to manage and perfect, but mixing white flour with wholemeal, rye and/or spelt will give a more interesting flavour.
Tip: the higher the percentage of white flour, the more the dough will normally rise and the less water it will normally need.
Put your dough into a transparent straight-sided container so you can see how it grows and develops. Make a note of the dough volume, as well as the time. This is important in tracking bulk fermentation later on, because that's measured from the time that the starter is added to the dough.
Cover and leave aside to rest in a warm place (eg in the oven with the oven light on) for 30 mins.
Step 3: Building up gluten (duration: 1.5 - 2 hours)
Once your dough has rested a bit, it's time to develop the gluten so the bread has a good structure. You have several options here, so pick the one that you find works best for the dough and for your schedule:
Stretch and folds: This simple option works for all dough types. Do 3 to 4 sets of stretch and folds, 30-45 mins apart.
Coil folds: This is similar to stretch and folds but works best on very soft, hydrated dough. Do 3 to 4 sets of coil folds, 30-45 mins apart.
Laminated dough: This works on most dough types. Do 2-3 sets of laminations, 30-45 mins apart.
You can also mix and match between the techniques as your dough develops - eg start with 1 set of stretch and folds, then laminate your dough 30 mins later once it has softened a bit.
For each technique, it's easier and far less messy to use a surface sprayed with water and your wet hands. Don't flour any surfaces for now.
Cover your dough while it's resting between sets and feel free to spray it with water as you go. This is a good way to hydrate it without it getting too sticky and unmanageable.
Stretch and fold technique
Coil fold technique
Laminating technique
Step 4: Finish bulk fermentation (duration: 2-6 hours)
Now you just have to leave your dough to rise, typically by 50-100% compared with its volume as measured in Step 2. The amount of rise to target will depend on factors like ambient temperature, starter strength, flour mix. Over time you will be able to 'read the dough' and decide when it's ready, but in the meantime use the guide in the image below.
measure the dough temperature (using your digital thermometer)
use the table below to see the target rise percentage and the approximate time this will take, using the volume and time you recorded earlier during the 'Getting started' step as a starting point
Cover your dough and leave it to rest in a warm place until it's risen to its target.
Step 5: Pre-shaping (duration: 30 -45 mins)
Once your dough has risen it's time to pre-shape it. The aim of this step is to create a nice tight ball of dough with good surface tension. You can use a dough tool for shaping, or your hands work equally well.
Pre-shape your dough and leave it covered for 30-45 mins.
Step 6: Shaping and resting in fridge (duration: 12-20 hours)
Lightly flour a lined banneton, then flour a work surface and your hands.
Shape your dough, put it in the banneton and leave in fridge to do a final proof for a further 12-20 hours. This step develops the sourdough flavour.
If you want a less sour loaf, you can just leave the dough in the banneton on the counter to proof for 1-4 hours and then bake.
Step 7: Baking (duration: 45-55 mins, plus oven pre-heat time)
Put your Dutch oven into your oven and pre-heat to 220 deg celsius.
When the oven has heated up, take the banneton out of the fridge and carefully flip the dough out onto a sheet of baking paper. Score it and spray with water, then put into the Dutch oven.
Bake with the lid on for 22-25 mins, then remove lid and bake for a further 22-25 mins until the crust is the colour you want.
Tip: if your dough just collapses and spreads when you tip it out, it probably won't bake into a nice shape because it doesn't have enough structure (eg it has over-proved). You can still save it! Just put the dough and baking paper into a loaf tin (instead of the Dutch oven), score it and spray, then cover with a bowl or upended second loaf tin and bake as described below. You may need to extend the baking times to around 25 mins covered and 25 mins uncovered.
Your bread is ready when it makes a hollow sound if tapped on the base.
Remove loaf from oven and allow to cool before cutting it. This is important because the bread continues to cook a bit after it's removed from the oven.
Some troubleshooting resources
The bulk fermentation guide
Videos and guides to help with the bulk fermentation stage
Check your crumb to see if you are over- or under-proofing your dough (opens as PDF)
Sourdough 'baker's math' calculator
This will help you figure out how much flour and water you should use for a given hydration level.