What is Sourdough?
 
Broken down to the bare basics, a simple loaf of sourdough consists of flour, water and salt. Add to that culture (also flour and water), warmth and time, and we get a loaf of bread that will hopefully turn you away from store-bought loaves for good.
 
An organic process (the oldest way to make bread, actually), baking a loaf of sourdough takes time and effort. Lots. It is after all the natural transformation of the above ingredients into something that will change your dietary life forever.
 
Why Sourdough?
 
A key part of the whole process is fermentation. During fermentation, naturally occurring yeast and lactic acid bacteria (LAB) work at breaking down the flour for food. LAB breaks down the flour to get carbohydrates for food, leaving sugars for the yeast. The yeast feed on the sugars, creating carbon dioxide, which causes the loaf to rise. Thus, flour is rendered into a state that is easily broken down and digested by us, being more suitable for people who suffer from certain digestive issues like gluten intolerance. Even those with a healthy digestive system will benefit, as their systems are not stressed, and over time will continue to maintain a healthy balance of gut microbes.
 
Acidity of the loaf inhibits mold development, so your bread lasts longer on your countertop (without chemical help).
 
The controlled release of sugars due to action by the LAB makes sourdough low GI by default (except for loaves with sweeteners).
 
Minimal processing.

​Basic Ingredients of Sourdough
 
Flour
 
The basis of all bread baking. Each grain consists of the bran (13%), germ (3%), and endosperm (84%). Big, commercial roller mills usually will sift out the bran and germ, and the endosperm is processed further for commercial use. Stone-milled flour on the other hand, is generally considered healthier as it retains more of the original vitamins and minerals in the wheat grain, as stone mills are usually colder. Roller mills operate at higher temperatures and so burn off some of the nutrients in the process.
 
Water
 
Water is the ‘link’ between the ingredients. Water temperature affects fermentation. Water volume affects crumb and texture. In Singapore, water can be used from the tap. Do not use NEWater or any type of de-oxygenated water. Water also provides food to organisms in the dough.
 
Salt
 
Salt, though used in small amounts in sourdough breads, is important as it strengthens gluten in the dough, controls fermentation and improves flavor. Always use sea/artisan salts as they are the least processed and therefore environmentally responsible. 

Starter maintenance
 
0.3 starter : 1 flour : 1 water

• Feed your starter 1-2 days prior to baking.
• Day 1 & 2: 

20g starter + 50g flour (I use 25g bread flour and 25g whole-wheat flour) + 50g water
 
Day 3:
About 4-6 hours before baking (aim is to increase the amount of starter by 3 times over 6 hours)
80g starter + 100g flour (I use 50g bread flour and 50g whole-wheat flour) + 100g water
 
For regular maintenance

• Feed your starter once every week or once every two weeks - 20g starter + 50g flour (I use 50:50 bread and whole-wheat) + 50g water 
• Leave it out for about 2 hours to increase the volume by 50% then refrigerate.

 
Here is how to make your own Sourdough Starter.

​Baker’s Percentage
 
A mathematical method to calculate the amounts of other ingredients relative to the total flour weight.
 
Basic Formula (always take into account that the starter has flour and water too)
 
Starter
Starter 10g
Flour 25g
Water 25g
Total 60g
 
Final Dough
Bread Flour       300g (100%)
Water                201g (70%)
Starter               60g (20% for 16-24 hours loaf fermentation)  
Salt                     7g (2%)
Total                   568g
 
Notes:
-For whole-wheat breads, substitute 10-30% whole wheat flour. When changing flours, always increase the quantity of water slowly by 5% and go by feel. This extra addition of water is called Bassinage.
-For same day bakes, increase starter to 40-60%. 4-6 hours loaf rise (fermentation) at room temperature.

Basic process
 
Autolyse 
Mix 300g flour and 201g water together in a bowl until well combined. Cover and set aside for 30 min – 2 hours.
 
Add starter 
Add 60g starter. Combine well, cover and set aside for another 30 minutes.
 
Add salt
Add 7g salt. With wet hands, knead the salt into the dough. Set aside for 30 minutes.
 
Bulk fermentation
Using “coil folds” or “stretching and folding” technique, work on the dough 3-4 times every 30 minutes until it starts to hold shape (about 2-3 hours in total). Once the dough starts to hold shape, continue to rest the dough for 1-2 hours until it increases in size by about 30%.

Poke test
You can check fermentation at this stage using the "poke test". With floured fingers gently poke the dough using your index finger - if it bounces up slowly it's ready. If it rises too fast, it's under-fermented (continue to rest and ferment). If it leaves a dent, it's over-fermented.
 
Shaping
Using lightly floured hands, stretch and fold the dough gently first into thirds. Rotate at a 90º angle, then roll it all the way up into a log. Lift it gently. Place it smooth side down into your banneton, seal the edges and butt cracks. 
 
Final Proof
Cover with a shower cap, rest at room temperature for about an hour, then cold-proof in the refrigerator at 4-5ºC for 16-24 hours.
 
Score and bake

• Pre-heat your oven to 250ºC with your lidded Dutch oven placed inside.
• Place parchment paper on your counter and gently flip your fermented loaf onto the paper.
• Score with a sharp blade at a 45º angle.
• Carefully take the hot Dutch oven out and place it on a heat-proof surface. Remove the lid and carefully place the sheet of dough into the Dutch oven.
• Drop 2 ice cubes on the side into the Dutch oven. Cover immediately and bake the covered loaf for 15 minutes. Ice cubes help create steam to prevent crust from forming and browning too quickly, & also help open up the bread to create an ear.
• After 15 minutes, remove the lid and bake further for 15-20 minutes or until golden-brown all over. Tap the bottom of the bread to hear a hollow sound – it means your loaf is ready
• Place your hot loaf on a wire rack to cool completely before slicing and serving. Sliced bread can also be frozen in airtight bags.

Here is a little guide to how you can create your owner starter. I have used 50% bread flour and 50% whole-wheat flour for my starter, for best results. Hope you give it a try and as always, leave any questions you may have in comments.

Day 1: Start with 50g bread flour + 50g whole wheat flour + 100g water - stir well, I leave it loosely covered in a glass jar for 24 hours.

Day 4: Set aside most of the fermented batter, leaving 2-3 tablespoons batter in the jar. Add 50g bread flour + 50g whole wheat flour + 100g water to the jar, stir well and set aside again for 24 hours. Don’t throw away the discard. The leftover batter you set aside can be used to make any of the delicious sourdough discard recipes below.

Day 7: same as day 4, 5 and 6. On day 7, I usually wait for the batter to double in size (3-4 hours after the feed) and use it to make your sourdough loaf.