Care of Sourdough Starter

Maintaining your starter in the refrigerator

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.

Take the starter out of the fridge. There may be a bit of light amber or clear liquid on top. Either drain this off or stir it in, your choice; it’s alcohol from the fermenting yeast. 

Remove all but 4 ounces (1/2 cup) starter.

Add 4 ounces (1/2 cup) non-chlorinated, room-temperature water and 4 ounces (a scant 1 cup) unbleached, all-purpose flour to the remaining starter. Mix until smooth, then cover.

Allow the starter to rest at room temperature (about 70°F) for 2 to 4 hours; this gives the yeast a chance to warm up and get feeding. After about 2 hours, refrigerate.

Maintaining your starter at room temperature

For frequent bakers who can maintain a twice-a-day feeding schedule:

Stir the starter well and discard all but 4 ounces (1/2 cup). Add 4 ounces (1/2 cup) non-chlorinated, room-temperature water and 4 ounces (a scant 1 cup) unbleached, all-purpose flour to the 1/2 cup of starter.  Mix until smooth, then cover. Repeat every 12 hours.

A note about room temperature: the colder the environment, the more slowly your starter will grow. If the normal temperature in your home is below 68°F, find a smaller, warmer spot to develop your starter.  For instance, try setting the starter atop your water heater, refrigerator, or another appliance that might generate ambient heat. Or, set it near a heat source (baseboard heater, etc.).  Another option: set the container of starter on a folded dish towel laid atop a heating pad on its lowest setting.

Getting ready to bake

If you’ve been maintaining your starter at room temperature, you may want to increase the volume of starter to the amount needed for your recipe. You can do this by feeding your starter without discarding, or by discarding all but 4 ounces and feeding that 8 ounces flour and 8 ounces water.

If your starter has been refrigerated, you’ll want to both increase its volume and raise its activity to a more energetic level. You can do this by giving it a couple of feedings at room temperature.

Take the starter out of the fridge, discard all but 4 ounces, and feed it as usual with 4 ounces water and 4 ounces flour. Let it rest at room temperature for about 12 hours, until bubbly. Repeat as necessary, every 12 hours, until you notice the starter doubling or tripling in volume in 6 to 8 hours. That means it’s strong enough to leaven bread.

For the final feeding, make sure you add enough flour and water to use in your recipe, with a little left over to feed and maintain the starter for the next time you bake. For instance, if your recipe calls for 1 cup (about 8 ounces) starter, add 4 ounces each water and flour. If your recipe calls for 2 cups (about 16 ounces) starter, add 8 ounces each water and flour.

Once the starter is bubbling and vigorous, remove what you’ll need for the recipe and set it aside. Feed the remaining starter with 4 ounces flour and 4 ounces water. Mix until smooth, and allow the starter to work for about 2 hours at room temperature before putting it back in the refrigerator.

Troubleshooting your starter

Living creatures sometimes get sick, be they humans, pets, or even sourdough starter. If you find yourself becoming a sourdough doctor, here are some symptoms and possible cures.

If your starter lacks acidity:

Feed with half whole-rye (pumpernickel) flour or  whole wheat flour for a few days. The extra nutrition in the bran and germ can increase the starter’s acidity.

Be sure your starter has a chance to ripen (develop) fully before it receives another feeding, before you use it in a recipe, or before refrigerating it. An ideal feeding regimen for a starter kept at room temperature (in the low 70s) is two feedings a day at 12-hour intervals.

Find a slightly warmer (in the mid 70s) area in which to ripen the starter after its feeding.

If your sourdough is too acidic:

You may be letting the starter ripen too long before using it. Once your starter is bubbling and vigorous, it’s time to make bread, feed it again, or refrigerate until its next feeding. Don’t let it become bubbly, rise, and then fall and start to “calm down;” that’s adding acidity to its flavor. Reduce the duration of ripening as necessary.

Ripen your starter in a slightly cooler area, so it doesn’t digest its meal of flour and water too quickly.

Reviving a dormant or neglected starter

Sometime you may find yourself with a starter that’s gone far too long without a feeding. Covered in a clear, dark liquid (alcohol, a by-product of yeast that’s been deprived of oxygen), the starter will lack bubbles or other signs of activity, and will have a very sharp aroma. Although the starter appears lifeless, its microflora will spring into action again as soon as they get a few good meals.

Stir the liquid back into the starter. Discard all but 4 ounces, and set the bowl or crock on the counter; you’re going to be leaving it at room temperature (at least 70°F) for awhile.

Feed the starter 4 ounces (1/2 cup) water and 4 ounces (a scant 1 cup) all-purpose flour twice a day, discarding all but 4 ounces (1/2 cup) of the starter before each feeding. It should soon become healthy, bubbly, and active.

Sourdough starters are hearty, and easily resist spoilage due to their acidic nature. The pH of a sourdough starter discourages the proliferation of harmful microorganisms. However, if your starter does turn ominously pink or red, shows signs of mold growth, or smells decidedly putrid, throw it away and begin again.

Long-term storage of starter

What’s the best way to keep your starter happy, healthy, and vibrant, when you know you won’t be using it for an extended period? The best way to preserve your starter – for a couple of weeks, a month, or even years – is to dry it.

1. Ready your sourdough starter for storage.

First, feed your starter as though you were going to bake with it. If it’s been stored in the fridge, take it out, and feed it with equal parts unbleached, all-purpose flour and lukewarm water. Let it rest, covered, until it becomes very bubbly and healthy looking.

2. Spread it out to dry.

Spread it onto two pieces of parchment paper. It helps to set each piece of parchment on a baking sheet, simply for ease of transportation. The starter should be spread as thinly as possible; use a spatula, an offset spatula, or a bowl scraper to help the process along.

3. Dry the starter completely, until it’s brittle.

Let the starter dry at room temperature until it’s completely and utterly dry. This will take a day (if you live, say, in Arizona, in a house without air conditioning), or up to three, four, five days – it totally depends on the weather.

If you live somewhere humid, can you dry your starter in the oven? Yes; but be careful. Rather than turning the oven on to warm it, use only your oven’s electric light, which will produce very gentle, even heat. You don’t want to risk turning the oven on and accidentally making it too hot, which would kill your starter.

Completely dry starter should peel easily off the parchment; when you pick a piece up, it will be brittle and easily snap between your fingers. If you have a scale, weigh it; if you started with 4 ounces starter on your parchment, it should weigh 2 ounces (or very close) when it’s completely dry.

4. Break it into pieces.

Break the starter into small chips with your hands, or place it in a plastic bag and pulverize it with something heavy.  You can run it through a food processor, but it isn’t necessary.

5. Store it airtight.

Store the starter airtight, preferably in a glass container. You want something totally inert, with an airtight cover; a glass jar is perfect. Date the jar and label it. Keep the jar of dried starter in a cool, dark place, if possible: not cool as in refrigerator, just not sitting in the hot sun, or over your woodstove.

6. Bring your sourdough starter back to life.

When you’re ready to revive the starter, measure out 1 ounce (or about 1/8 of it, if you’d been following a regular feeding pattern and had about 8 ounces starter on hand at the beginning of the drying process). Don’t have a scale? Well, depending on the size of your chips, this will be between 1/4 and 1/3 cup.

7. Mix the starter with lukewarm water.

Place the dried starter chips in a large (at least 1-pint) container. Add 2 ounces (1/4 cup) of lukewarm water. The water should barely cover the chips; tamp them down, if necessary. Stir the chips/water occasionally; it’ll take 3 hours or so, with infrequent attention, to dissolve the chips.

8. Feed it with flour.

Once the mixture is fairly smooth/liquid, with perhaps just a couple of small undissolved chips, feed it with 1 ounce (about 1/4 cup) of unbleached all-purpose flour. Cover it lightly (a shower cap works well here), and place it somewhere warm, such as in an electric oven with the light turned on, which should hold a constant temperature between 85°F and 90°F.  You can certainly keep your starter out of the oven, at room temperature; just understand that this whole process will take longer. The cooler the room, the longer it takes sourdough starter to work.

9. Let it rest somewhere warm until it bubbles.

Let the starter work for 24 hours. At the end of that time, you should see some bubbles starting to form. Remember, this is at about 85°F; if your temperature is lower, this will take longer.

10. Feed the starter again.

WITHOUT DISCARDING ANY OF THE STARTER, feed it with 1 ounce of lukewarm water, and 1 ounce of flour. Cover, and put back in its warm spot. After “X” hours (depends on your kitchen), you should see some serious bubbling.

11. And again.

Feed the starter again – 1 ounce of lukewarm water, 1 ounce of flour – cover, and wait. Again, you’re not discarding any at this point.

12. Put the starter back on its regular feeding schedule.

Your starter is ready to return to its former life – and its regular schedule. DISCARD all but 4 ounces (about 1/2 cup). Feed it again, this time with 4 ounces each lukewarm water and flour. (That’s 1/2 cup of water, and about 1 cup of flour.) This time, it should really expand quickly. Your starter is now revived and healthy.

13. At last – you’re ready to bake!

To ready the starter for baking (while saving enough for another day), feed it again. Discard all but 4 ounces, and feed the remainder with 4 ounces each lukewarm water and flour. Let it become bubbly – and let the baking begin.

From King Arthur Flour