You can try to revive it by pulverizing it and adding water, then feeding it on a regular schedule. But if it doesn't respond at all (no growth, no bubbles) after three or four days of twice-a-day feedings, you might as well start over.
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.
In a small bowl or jar, mix 5 grams of dehydrated sourdough starter with 15 grams of 80 °F water. Allow the starter and water to sit for about 2 hours, or until the dried starter dissolves. Stir in 15 grams of flour. Cover and put in the Sourdough Home or Proofer at 78 °F overnight, or for 12 - 14 hours.
Allow the starter to rest at room temperature (about 70°F) for at least 2 hours; this gives the yeast a chance to warm up and get feeding. After about 2 hours, replace the starter in its storage container and refrigerate.
First, take it out of the fridge and let it come to room temperature. Then, feed it with equal parts flour and water (by weight) and let it sit at room temperature for a few hours. After that, it should be ready to use in your baking!
Please note: rehydrating and reviving your new starter can take 4 to 14 days before it is ready to be used. So plan accordingly and be patient. If you can't start your starter right away, store it in a cool dry place until you are ready, but for the sake of freshness and viability rehydrate it as soon as possible.
You can try to revive it by pulverizing it and adding water, then feeding it on a regular schedule. But if it doesn't respond at all (no growth, no bubbles) after three or four days of twice-a-day feedings, you might as well start over.
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. Reviving a sourdough starter that has been stored in the fridge for a longer period of time is a good idea.
A sourdough starter is dead when it doesn't respond to regular feedings. If this is the case, the starter needs regular refreshments to be brought back to life. You may also see mould or discolouration, if this happens it's often best to throw it out and start again.
However, if you see a pink or orange tint or streak, this is a sure sign that your sourdough starter has gone bad and should be discarded. The stiff starter above was left out at room temperature for two weeks. It's definitely time to throw it out and start over.
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.
Signs of a Bad Sourdough Starter
If your starter has mold growing throughout it (not just a little on top), or if it smells really foul (not just super sour), or if it turns an odd color (not just gray, which is normal, but pink or green), it may be time to start over.
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.
Common Signs of a Bad Starter
The engine won't turn over. The most common signal that your starter has a problem is if nothing happens when you turn the key or push to start. Unusual noises, such as clinking, grinding and whirring. If you ignore these sounds, it can eventually lead to damage to the engine flywheel.
If at one point your starter was all bubbly and happy, and now it's not rising anymore, it's possible that it needs a few extra feedings to boost the yeast development. Assuming you understand how temperature and ingredients can effect the rise of your starter, try feeding it 2x per day and see what happens.
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.
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).
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.
If you're making a starter from scratch you may be shocked when your starter stops bubbling as actively around the fourth day. That's normal! The vigorous activity of a new starter does eventually slow down. Just keep it on a regular feeding schedule and it'll mature into a reliable bread leavener.
To revive, take your jar out of the fridge and let it sit on the counter for an hour or two to warm up. The mixture may or may not be bubbly like mine below, but either way, stir it so everything is reincorporated.
Because, yes, you can overfeed your sourdough. The explanation is quite simple: if you add too much water and flour, you're basically diluting the natural population of yeast and bacteria. This means that your sourdough starter will not rise much and will not be very bubbly.
Your sourdough starter will not be ready for at least 14 days from when you started it. You can try to bake with it before 14 days, but honestly, you'll be rewarded with better bread if you wait.
REVIVING A LOAF FOR FRESH EATING
Splash some water over the top of your bread, just enough to become slightly damp. Place the loaf in a 250°F oven for 5 to 10 minutes. Watch it closely and remove it when warm. Too long in the oven and you'll get dried-out toast.
This works because the brushes wear out which results in an inadequate electrical contact. By gently tapping on the back of the starter with the hammer, the brushes are knocked back into place so they can make contact one more time.