A mature sourdough starter can last for several weeks to months if kept in a refrigerator without being fed.
If you plan to use it often, you can store it for up to two months without feeding.
The oldest known sourdough starter is said to have originated from clay pots unearthed in Egypt. Seamus Blackley baked a loaf of sourdough bread using yeast harvested from 4500 year old clay pots. What is this? If you want to read more about this 4500 year old sourdough starter, go here.
Sourdough starter can be frozen, if you would like to store it for a long period without feeding. To do this, double the amount of flour added at feeding so that it is a very thick paste, place in an airtight container and freeze for up to 1 year.
If the starter isn't dried and has not been fed regularly, then it could become moldy and no longer viable. But in general terms, there's no such thing as a starter that's too old, provided it's been cared for. Does sourdough starter get more sour as it ages?
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. If it's more than 3 days AND you have a warm kitchen, you'll have to make the call based on how well you know your starter.
Maintaining A Sourdough Starter:
Leaving it out on the counter, it will need to be fed equal parts water and flour every 12-24 hours. Warmer homes or frequent baking will require more frequent feeding (around every 12 hours), while colder homes every 24 hours.
8. A Mature Sourdough Starter is More Sour Than a Young One. If you have made a starter from scratch, it doesn't fully mature and develop its full depth of flavor until a good few months down the line. A more mature sourdough starter will give a more sour flavor.
The idea that a starter with greater age has more flavour or some other beneficial property are false. Too many myths about starters and sourdough in general allow people to make these claims, which generally aren't true.
If your recipe calls for more than 227g (about 1 cup) of starter, feed it without discarding until you've reached the amount you need (plus 113g to keep and feed again).
If you don't discard your sourdough starter, it will grow too big and be unmanageable. Not to mention you will go through an unmentionable amount of flour.
15. What if I miss feeding my sourdough starter? If you miss one of your starter feedings, it'll be just fine. Give it a feeding when you next remember it needs one, and continue with your daily feedings as usual.
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.
SEVERE NEGLECT: If you neglect your starter long enough, it will develop mold or signs of being overtaken by bad bacteria. Mold can appear in various colors and is typically fuzzy in appearance. Bad bacteria is generally indicated by an orange or pink tinge or streak.
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.
Float Test: You can perform a float test to check if your starter is ready. Take a small spoonful of the starter and drop it into a glass of water. If it floats, it indicates that the starter is sufficiently active and ready for use.
Pinch off a piece of dough from your sourdough before you place it into it's fermentation container. Place the small piece of dough into a small shot glass. It will be easy to see when the dough in the glass has doubled. When this happens, the dough in your container should have also finished its fermentation.
If left unfed it can start to grow mold and bacteria. At that point, a starter should be thrown out and started over. Any pink, orange, or grey color should be discarded and a brand new starter should be made. A sourdough starter does have a tangy smell to it but it should never have a foul smell.
Dehydrate it
And it will last many months on the shelf with no power required to keep it cool. Many bakers dehydrate their starters as an “insurance policy” if anything happens to their sourdough culture in it's day-to-day baking life.
Feeding sourdough starter
You can leave the starter in the refrigerator for 3 to 4 days at a time between feedings. We recommend feeding sourdough starter at least twice a week for best results. Remember, if you're planning to make bread on a given day, you'll feed sourdough starter the night before you bake.
Generally a starter can stay at room temperature without feeding for a maximum of 3 days. After that you will need to give the starter few feedings before you can use it again. This is because it will become less strong and it will need time and food to become strong again.
Do I have to feed my sourdough starter twice a day? No. You can scale back to once a day or even scale up to three times a day, whatever works for you and your schedule. I like to feed it at least once a day to keep it strong and ready for baking.