Reviving a Sourdough Starter
Sourdough Starter Primer
A systems analyst's mantra says, "It takes a consistent process to produce a consistent product." I learned this when I was a programmer and systems analyst. I had a graduate course in it when I was running a bakery. And I've had it reinforced with many letters I've received over the years I've been running the Sourdoughhome.com web site. People don't pay attention to their starter. One time, the bread rises in 4 hours and tastes great. Another time it rises in 2 hours and has no taste. Another time it takes 16 hours, there's hardly any rise, and the bread is as sour as some kids nasty sourstuff candy. And then the people become sourdough dropouts. The first key to consistent sourdough results is a consistent starter.
This page has two focuses. One is the normal revival of a refrigerated storage starter to turn it into the consistent starter you need in order to get consistent results. The other focus is an attempt to recover a starter that has been ignored for far, far too long so you can rehabilitate it. Let's talk about the easy case first.
Reviving a Healthy Storage Starter
In the Storing a Starter page we talk about how to store a starter. If your storage starter was fed just before you put it into the refrigerator, and it has been in storage for less than a week, you can probably just use the starter. Measure it, put the unused storage starter back in the refrigerator, let starter you are going to use come to room temperature and use it. Remember that a starter at room temperature needs to be fed no less than twice a day, so don't leave this starter out overnight, or for a similar length of time, without feeding it. It has been eating the available starch in the starter while in the refrigerator and if you're going to let it sit a while, it needs a real feeding.
If your storage starter has been in storage for more than a week, you really need to take a little more time reviving it whether you intend to bake with it or it's just time to revive it to make sure it's healthy. I like to feed the starter for at least three days before using it or putting it back in storage. I'll take a teaspoon (about 6 grams) of storage starter from the jar in the refrigerator and put the jar back in the refrigerator. You can use the starter in the refrigerator, a teaspoon at a time, for about a month before you need to revive it. Once the storage jar is back in the refrigerator, I add 1/4 cup (about 50 grams) of water to the teaspoon of starter and vigorously stir them together. Then I add 1/2 cup (about 50 grams) of flour (if you are using 1/2 cup, the flour should be sifted and spooned into the 1/2 cup measure) and stir vigorously again. Twelve hours later, I add the same amount of water and flour again.
If I am feeding the starter to revive it, I'll start discarding 1/2 the starter and then feed another 1/4 cup water and 1/2 cup flour every 12 hours or so. When the starter is doubling nicely between feedings, I'll feed it one more time, clean out the storage jar, put the freshly revived starter into the jar, and then put the jar back into the fridge. Again, the key success strategies are to feed the starter until it is doubling between feedings, to fill the cleaned jar no more than 1/2 full, and to refrigerate immediately after you feed the starter.
If I actually want to bake with the starter (remember baking? the point and goal of the exercise?), I don't discard any more starter. Instead every 12 hours I double the amount I am feeding the starter. So, my next feeding is 1/2 cup of water (about 100 grams) and 1 cup (about 100 grams) of flour. Twelve hours later, 1 cup (about 200 grams) of water and 2 cups (about 200 grams) of flour. My goal is to double the starter with each feeding so I'll have enough to bake with in two or three days. If you weigh your ingredients it is very easy to calculate how much starter you will need and how much each feeding should be so you'll have enough starter in two or three days with no wastage. The goal here is to have enough active healthy starter to bake with in 3 or so days with little or no starter left over.
Please note, the amounts in the volume measurements and weight measurements are not the same. In each case, I am using a convenient measurement. There are actually 130 grams of so of flour per cup, and 238 grams of water per cup. It's easier to use even amounts where one can. I don't like recipes that call for 1/4 cup less 1 TBSP, or 1/4 cup plus 1 TBSP. Yeah, sometimes things work out that way, but I'd rather avoid them.
But there are some caveats here. Dr. Ed Wood, who knows more about starters than just about anyone alive, has said he's never had a starter he couldn't revive. It must help to have medical training. However, other people point out that it's not always clear if the starter your revived is the one you started with. Kinda like in the book "Pet Semetary," you can wind up with a starter that's similar to what you had, but not quite the same. And there are a few conditions that make your starter not worth the trouble of trying to revive it. So, let's look at the science experiment you are pretending used to be a sourdough starter and see what we can do with it.
An Important Note - I get a fair number of emails asking if I think a starter that's been stored like this, or forgotten SO long can be revived. I really can't predict if your starter can be revived. Was it healthy before it was ignored? Was it already damaged? In the end, the starter will tell you by reviving or not reviving. I used to answer ALL my email. However, at best I don't answer it as quickly as you - or your starter - would like. However, I am sure that if you wait a week for my email before you start trying to revive your starter, your odds just went down. When in doubt, try to revive it! It's a little flour and water and a little time. It's worth the risk, so just do it!
Our first goal is to get a good sample of the old starter. How we do that depends on the condition of the starter. If there is a layer of liquid on top of the starter, it is called hooch - old miners used to drink it when they were desperate for a drink. Yes, it has low-grade alcohol in it.
Was there mold on the hooch? Is there mold on the top of the starter? If not, smile and skip to the next paragraph. If there is, go to the silverware drawer and get a handful of spoons. Mold is normally a surface condition, so we'll try to get some good starter from lower levels of your starter jar. Start by scraping off the mold, being very careful not to stir the starter - you'll only stir the mold into the starter. When you think it's all gone, get a clean spoon and scrape a bit more starter off the top. Now go on to the next paragraph....
If there was non-moldy hooch on top of the starter, just pour it off. We are trying to revive a long forgotten starter, and the concentration of alcohol and other waste products in the hooch won't help with the revival. With a fresher starter, we might stir it back in. But not this time.
Chances are good that the top of your starter has discolored, having turned gray from exposure to air or stuff in the hooch. You'll want to use a clean spoon to remove the darker layer, revealing a lighter colored layer beneath. If you just removed the mold, chances are good you don't need to worry about the discolored surface layer - it was scraped away with the mold.
At this point, you should have a light colored layer of starter exposed, free of hooch and mold. Use a clean teaspoon to transfer a teaspoon (about 6 grams) of the starter to a clean bowl. Reseal the jar of starter you are trying to revive and put it back into the refrigerator - sometimes the first attempt at revival doesn't work, and you'll need to go back to that starter.
Now add 1/4 cup of water (or about 50 grams) and stir the starter very vigorously. Add 1/2 cup of flour that was sifted and spooned into the 1/2 cup measure (or about 50 grams) of unbleached, unbromated white flour and stir again. This is very important, even if you are a whole grain enthusiast. Whole grain flours have many organisms on them that would compete with the organisms in the starter you are trying to revive. We want to give your starter the best chance of reviving. Whole grains are great for starting a starter, but not for reviving one. Now, start the usual maintenance feedings. Twelve hours later, another 1/4 cup (50 grams) of water and 1/2 cup (50 grams) of flour.
Now the volume of starter is where you want it, so every 12 hours pitch half the starter and feed the remaining starter another 1/4 cup of water and 1/2 cup of flour - or about 50 grams of each. While I appreciate thrift, frugality and the desire to save starter, I would actually discard the starter at this point. You don't know what critters are working in your starter, and, until it is stable again, I'd treat it with caution.
Your starter should take off in 2 to 3 days. If it is slow, or if it isn't responding, switch to three feedings a day, with each feeding being enough to triple the size of the starter. Do that by discarding 2/3 of the starter and adding 1/2 cup (100 grams) of water and 1 1/2 cups (100 grams) of unbleached unbromated white flour. If the starter doesn't start working well in another 2 days of this process, it's time to pitch this starter and go back to the storage starter in the fridge and start over.
There is one condition that seems to be irreversible. Sometimes you mix up a dough with your starter and the dough quickly gets very soft, it turns into a liquid. And the starter has a strong smell of acetone, or cheap fingernail polish remover. If this has happened, bacteria that can eat the protein in your starter have taken it over. Normally starch-eating bacteria are in your starter. If you don't feed it often enough, the protein-eating bacteria can take over.
Do you remember back in the Starting A Starter page when I talked about how a starter was like a weed patch that you were cultivating? At this point, one of the weeds has again taken over. And it is a very hard weed to eradicate. I know of two people who were able to beat back the protein-eating bacteria and have their old starter back. However, the other guy and I both found that the next time we skipped a starter feeding the bad bacteria took over again. The starter was undependable and unstable. Pouring it down the drain and starting over was the only real answer for me.
It is worth mentioning that the above paragraph has prompted more than a few conflicting comments from experts. Didier Rosada, who has trained a number of Coupe du Monde de Boulangerie world champion baking teams, says that you are better off just pitching it and starting over. Debra Wink a well known hobbyist baker and biologist says she's recovered starters like this in 7 to 10 days. My view - in 7 to 10 days I can start a new known good starter, so I'd rather just start over.
After an aggressive feeding campaign to get a starter back alive you may find that the starter just doesn't have the taste it used to. Usually that is because the yeast is dominant in your starter. Rapid feedings seem to favor the yeast. Feeding the starter part whole wheat or rye flour will help restore the balance. About 5% whole wheat and 95% white for a few feedings seems to take care of this in a few feedings. If you are measuring by volume, put a tablespoon of whole wheat or rye flour in each measuring cup, then fill them with white flour. The starter should return to normal in short order.
Once you think your starter is doing well, make some bread with it. If the bread is OK, then your starter is probably OK, so you can pitch the rest of the stored starter you've been trying to revive and save your recovered starter in the fridge.
An ounce of prevention is worth several pounds of flour.... so I hope you never have to use the ugly forgotten starter recovery notes!