Makes: one sourdough culture of infinite size and potential
Note: The choice of flours is less important here than it will be when it comes time to bake. That said, you are more likely to be successful most quickly if you are working with unbleached and/or organic flours, and even more so if you can use a mixture of white and whole wheat or rye flour. (Many people who had access only to bleached flour have struggled to get their starters to work. But others have had success using all kinds of flour during the quarantine, so you should use whatever you can get until you can replace it with something better.) Filtered or bottled water is preferable as it will be free of chlorine that might kill the microbes we are trying to coax into being. If you are using a mix of white and whole grain flours, you’ll need to use more water as indicated below. Your starter container should be covered well but loosely; inverting the mason jar lid will allow the culture to breathe while still preventing it from drying out. Translucent containers are useful to allow you to see what is going on under the hood without needing to remove the lid, and narrow ones do a better job of letting you see when the mixture is expanding in volume.
Ingredients & equipment:
2 small, lidded containers, such as 4-ounce mason jars
1 larger, lidded container, such as a 16-ounce mason jar
About 3 cups of white flour (or, better yet, an equal-weights mixture of white flour and whole-wheat or rye)
Water (filtered or bottled if possible)
The Start (day 1):
Using spoon, mix 10 grams (4 teaspoons) of your flour or flour mixture and 10 to 15 grams (2–3 teaspoons) of lukewarm (75F) water in small container (mixture should resemble thick muffin batter). Cover and let sit at warm room temperature (70 to 80 degrees) until bubbly and fragrant—even pungent—24 to 72 hours.
Check your jar every 24 hours for activity. When it’s woken up, it should be bubbly and wet-looking, and will likely have a pungent, even offensive aroma (not to worry, this is totally normal—if it smells at all, it won’t usually smell good, at least not until it’s close to being mature). If it isn’t active yet, put it back in its warm spot and check again in another day or so.
When it’s active:
In your second small container, place 10 grams (4 teaspoons) of your flour or flour mixture, 10 to 15 grams (2–3 teaspoons) of lukewarm (75F) water, and 10 grams (2 teaspoons) of the previous batch until uniform. Cover and let sit at warm room temperature for 24 hours. Place the leftovers from the previous batch in the fridge as a backup.
Repeat this feeding (or “refreshment”) procedure every 24 hours, discarding the contents of the backup jar, cleaning it out thoroughly, and using it to store that day’s new culture. (That day’s old culture then becomes the new refrigerated backup. This way you go back and forth between the two small jars.) Over time the look and smell of the culture will evolve, and it will likely get quite quiet. This throws a lot of people off, since they think it should look bubbly and smell fragrant the whole time. It likely will not; do not worry about this, just repeat as directed.
When it gets really active:
Somewhere between 7 and 14 days after the first refreshment, your nascent starter should start getting very active, meaning it is bubbly and fragrant after 12 hours or less, and it starts to smell yeasty or bread-like. If so, start refreshing it every 12 hours instead of every 24. (Do not jump the gun here—if it takes longer than 12 hours, stick to once-daily refreshments.)
You should also at this point begin collecting the contents of the backup jars in the third, larger jar, rather than tossing them out. Seal and store this jar in the fridge next to each day’s backup. This is your “sourdough discard”, which can be used in recipes once you have collected enough (at least 1/2 cup). Don’t start collecting discard until it smells pleasant, however. (More on what to do with your sourdough discard is coming soon, so stay tuned.)