The last time I used my sourdough starter was a loooong time ago. I did a series of posts about baking with sourdough, then moved on to other baking projects.
The great thing about a sourdough starter, however, is that it can hang out in the back of the fridge for months and then be revived and ready for baking in just 48 hours.
Any old starter will have a layer of liquid sitting atop the flour slurry. The longer the starter sits the darker the liquid gets. It might not look very appetizing, but this liquid acts as a preservative. It is alcohol from the fermentation process and prevents anything from growing in the starter. Stick your nose in and take a sniff – does it smell yeasty, with no “off” odors? Then you’re all good to go. Inspect the sides of the storage container and the surface of the liquid. There shouldn’t be anything growing. If you do see pink mold growing, unfortunately your starter is contaminated. Dump it out and start from scratch. This is unlikely to happen.
Pour off the liquid. The surface of the starter doesn’t look any more appetizing. But just below the surface, the starter is still nice and white. Stir everything together and fill a half-cup measuring cup with starter. Dump the rest down the sink and thoroughly wash the container.
In the now-clean container, pour the reserved half-cup of starter back in, then mix with 8 ounces of water and 8 ounces of all-purpose flour. With this new food, the sourdough yeast microbes will wake back up and start feeding. After one day, the yeast won’t be at its maximum strength yet. As seen in the photos above, while the volume of starter increased some, it wasn’t that dramatic.
After 24 hours, reserve half a cup of the starter, dump the rest down the sink, then add another 8 ounces each of fresh flour and water. Let the starter sit and grow again for another 24 hours.
Repeat the process a third time. Reserve half a cup of starter, dumping the rest. Add 8 ounces each of flour and water. By now, the starter will be very active and ready for baking. After just an hour or two (see the above photos), the starter will be ready for baking.
If it’s not baking time yet, put the starter back in the fridge. If it only sits for a few days, it will just need one feeding to be ready for baking.