If your sourdough starter is new and less than a month old, it might not be able to survive very long without feeding. I wouldn't go more than 24 hours without feeding a very young sourdough starter (it may survive longer than this unfed however you will leave it open to the risk of mold).
And if you miss a day or two of feeding (or a week, or two weeks, or...), don't worry. Your starter can almost certainly be revived by feeding it every 12 hours until it's healthy, then putting it back on its regular feeding schedule.
Warmer homes or frequent baking will require more frequent feeding (around every 12 hours), while colder homes every 24 hours. Storing your sourdough starter in the fridge will require feeding around once a week. It can, however, be stored up to two months in the fridge without being fed.
Yes, after your starter is established (about 10 days after you created it), you can move it from room temperature storage, where you feed it everyday, to the fridge. A starter stored in the fridge can be fed once a week. If you plan to use it often, you can store it for up to two months without feeding.
The best way to tell if your sourdough starter is dead is if it does not respond to regular feedings. When you add fresh flour and water to the mix, you should see it come back to life through bubbling. Feeding it means adding fresh flour and water to keep the beneficial bacteria and yeast alive.
If it smells yeasty and not too sharp, if the color is still pale ivory (and not brown or pink), then it's probably fine. The rule of any kitchen is “When in doubt, throw it out,” but I wouldn't panic and toss your starter if you only missed 1-3 days of feeding.
You will either see mold or discoloration (generally pink or orange). If you see either of these things, you will need to toss your starter. The smell is usually a big give away. A starter that has orange or pink discolouration will usually smell absolutely foul.
A mature sourdough starter will reach its peak around 2 to 4 hours after being fed. If it's particularly cold, or you've given it a huge feeding ratio, this could be extended to 12 hours.
Subsequent feedings: Feed exactly the same way as the second feeding. Continue feeding your starter every 12–24 hours until it doubles in volume every 8–12 hours, has a pleasant, yeasty smell, and passes the float test (see note).
Feed ¼ cup (2 ounces) starter with ½ cup (2½ ounces) all-purpose flour and ¼ cup (2 ounces) water twice daily (approximately every 12 hours) and let it sit, covered with plastic wrap, at warm room temperature.
Sourdough starter fridge
Feed the starter before placing it in the fridge. Either 1:1:1 if you plan to use it within the next day or two, or 1:2:2 if it will be longer (up to 10 days). When you're ready to bake again, take it out a day before you need it. Give it a feed or two before using it to get it active again.
The very short answer is, your sourdough starter generally will be at its peak anything between 4 and 12 hours after feeding. The optimum time to use it will be when there are lots of bubbles at its surface and it has has physically risen to its peak level, just before deflating back down again.
You must discard some of your sourdough starter each time you feed it. You'll discover that discarding is necessary to build a healthy and thriving sourdough starter - but it's not actually as wasteful as you might think.
Myth 7: You can't overfeed sourdough starter.
While starters do need regular feeding, it is possible to overfeed one. Each time you feed a starter, you thin out the population of microorganisms by adding flour and water. The remaining yeasts and bacteria eat the new flour and multiply, rebuilding the population.
If a sourdough starter is not bubbly, it may require more frequent feedings. If feeding every 12 hours, increase to feeding every 8-10 hours, to make sure the culture is getting enough food. Check the temperature in the culturing area. Sourdough likes a temperature between 70°F and 85ºF, around the clock.
For most home bakers, daily feeding is impractical; so you'll need to store your starter in the refrigerator and feed it once a week.
Feed the remaining 1/2 cup (113g) starter as usual, with equal parts (113g each) flour and water. Mix until smooth and let the starter rest for about 2 hours at room temperature before stowing it back in the refrigerator.
At room temperature (70 F), sourdough discard should last about 1-2 days. Beyond that, it won't go bad necessarily, it will just become more acidic as time goes on (especially in warm weather). Not ideal for sweet recipes. In the fridge, it will keep for about a week or so, and in the freezer it will last indefinitely.
Scrape down the sides and cover with a tea towel secured with a rubber band. Place the jar at room temperature for 24 hours, until you begin to see the mixture bubbling up. It is important that you stir the sourdough starter every day in the morning and in the evening.
But before that happens, your starter will give you a sign that it's hungry. According to King Arthur Baking, it will throw off tons of "hooch," the alcoholic liquid that collects on top of the starter as it sits. Some hooch is fine, the outlet explains, even hooch that has changed color and gone dark.
Let your starter rest at warm room temperature for 12 hours
Your starter will wake up more quickly than it might have. Despite showing absolutely no activity at all after its first feeding (and 12-hour rest), once I gave the starter a second feeding it just about doubled within 5 hours.
To revive your old sourdough starter (or make starter more active), try feeding it with half regular flour (bread flour or all-purpose) and half wheat or rye flour. Rye seems to make sourdough starter especially bubbly! Your starter may be cold. Use a thermometer to monitor the temperature where the starter is stored.
Generally, feeding it once a day is a good rule when leaving your starter on the counter. Feeding it less than this can leave your starter open to mold and harmful bacteria, however you can also overfeed a sourdough starter.
Sourdough starters require regular feedings to stay active. If you don't discard the excess, eventually you'll have more starter than your feedings can sustain.