All About Sourdough

You can make your own sourdough starter at home. All it takes is flour, water, warmth, and time. Once you make it, the starter needs to be fed and cared for. But its requirements are simple; with a minimum of effort, you can keep starter on your counter, or in the fridge, to use whenever the impulse strikes.

How to make your own starter from scratch

There are lots of other ways to make a starter; as well as many types of starters. We’ll concentrate here on a typical American sourdough starter, which begins with whole-grain flour, and is subsequently fed with all-purpose flour. This is the easiest type of starter to successfully maintain, and it will create delicious sourdough breads, pancakes, pizza crust, and other tasty treats.

It takes about a week to develop a starter that’s strong enough to use for bread baking. Variables like the temperature and humidity of your kitchen, and the flours and feeding schedule you use, will affect the amount of time it takes to make a starter that’s ready to use in bread.

Sourdough Starter

The following timeline assumes you can find a relatively warm place (68 degrees F to 70 degrees F) to grow your starter. More on that below.

Day 1: Combine 4 ounces (1 cup) whole rye flour (pumpernickel) or whole wheat flour with 4 ounces (1/2 cup) non-chlorinated cool water in a non-reactive container. Glass, crockery, stainless steel, or food-grade plastic all work fine for this.

Note that whole grain flour (whole wheat or rye) is used at the beginning of the process. This is because whole grains contain more nutrients and sourdough-friendly microorganisms than all-purpose flour.

It’s also important to feed your starter with non-chlorinated cool water; from now on, we’ll refer to this simply as “water.”

Stir everything together thoroughly; make sure there’s no dry flour anywhere. Cover the container loosely and let the mixture sit at warm room temperature (about 70 degrees F) for 24 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 degrees F, we suggest finding 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.

Day 2: You may see no activity at all in the first 24 hours, or you may see a bit of growth or bubbling.

Either way, discard half the starter (4 ounces), and add to the remainder 4 ounces (a scant 1 cup) King Arthur Unbleached All-Purpose Flour, and 4 ounces (1/2 cup) cool water (if your house is warm); or lukewarm water (if it’s cold).

Mix well, cover, and let the mixture rest at room temperature for 24 hours.

Note: Why do you need to discard half the starter? It seems so wasteful…

Well, it’s necessary for three reasons.

First, unless you discard, eventually you’ll end up with The Sourdough That Ate Milwaukee – too much starter.

Second, keeping the starter volume the same helps balance the pH.

And third, keeping the volume down offers the yeast more food to eat each time you feed it; it’s not fighting with quite so many other little yeast cells to get enough to eat.

Also, you don’t have to discard it if you don’t want to; you can give it to a friend, or use it to bake. There are quite a few recipes on our site using “discard” starter, including sourdough pizza crust, sourdough pretzels, and my all-time favorite waffles.

Days 3, 4, & 5: By the third day (pictured top left), you’ll likely see some activity – bubbling; a fresh, fruity aroma, and some evidence of expansion. It’s now time to begin two feedings daily, as evenly spaced as your schedule allows.

For each feeding, weigh out 4 ounces starter; this will be a generous 1/2 cup, once it’s thoroughly stirred down. Discard any remaining starter.

Add 4 ounces (a scant 1 cup) King Arthur Unbleached All-Purpose Flour, and 4 ounces (1/2 cup) water to the 4 ounces starter.

Mix the starter, flour, and water, cover, and let the mixture rest at room temperature for approximately 12 hours before repeating.

Repeat two-a-day feedings on days 4, 5, and as many days as it takes for your starter to become very active.

After about a week of consistent feeding, your starter should be ready to use in a sourdough bread recipe.

How do you know when your starter is ready to use?

After 12 hours, the starter will have risen nicely. You’ll see lots of bubbles; there may be some little “rivulets” on the surface, full of finer bubbles.

Also, the starter should have a tangy aroma – pleasingly acidic, but not overpowering.

The starter should at least double in volume 12 hours after it’s been fed.

Once the starter is ready, give it one last feeding. Pour off all but 4 ounces. Feed as usual. Let the starter rest at room temperature for 6 to 8 hours; it should be active, with bubbles breaking the surface.

Remove however much starter you need for your recipe (no more than 8 ounces, about 1 cup); and transfer the remaining 4 ounces of starter to its permanent home: a crock, jar, or whatever you’d like to store it in long-term.

Ah, success…

But wait – what if things haven’t gone exactly according to schedule?

No worries. If, after a week, your starter isn’t ready, don’t lose heart; keep feeding it regularly, and it will gain strength – really!

Be patient. The conditions in your kitchen may be more or less conducive to building a starter, depending on room temperature, the season, humidity, or how much you’ve been baking.

Remember, the keys to developing a successful starter are using good (unbleached) flour; having a consistent feeding schedule, and ripening (growing) the starter in an environment that’s adequately warm (at least 68 degrees F, and preferably in the 70s).

When your starter is strong enough, it’s time to go ahead and make your favorite sourdough bread.

Once your starter has been fed, and you’re ready to mix up your bread dough, you’ll want to reserve and maintain a small portion of the ripe (fed) starter (about 4 ounces; about 1/2 cup, stirred down) for future baking. Unless you plan on continuing to feed the starter twice a day, refrigerate it for future use.

Maintaining your starter at room temperature

Room temperature is the best environment for the yeast and lactobacilli that inhabit your starter, and you can learn a lot about your starter by observing a twice-a-day feeding regimen with the starter at room temperature.

If you’re willing to maintain your starter at room temperature by feeding it twice a day, here’s how:

Stir the starter well and discard all but 4 ounces. Add 4 ounces non-chlorinated, room-temperature water (hereafter known simply as “water”) and 4 ounces King Arthur Unbleached All-Purpose Flour (hereafter known simply as “flour”). Mix until smooth, and cover. Repeat every 12 hours.

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.

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 starter. Use this “discard” to make pancakes, waffles, cake, pizza, flatbread, or another treat; Buttery Sourdough Buns is one of my favorite “unfed” sourdough recipes. Or, simply give to a friend so they can create their own starter.
Add 4 ounces lukewarm water and 4 ounces flour to the remaining starter. Mix until smooth, and cover.
Allow the starter to rest at room temperature (about 70 degrees F) for at least 2 hours; this gives the yeast a chance to warm up and get feeding. After about 2 hours, refrigerate.

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, and feeding it 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) istwo 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 known as hooch (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 degrees F) for awhile.
Feed the starter 4 ounces water and 4 ounce all-purpose flour twice a day, discarding all but 4 ounces 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 turns ominously pink or red; shows signs of mold growth, or smells decidedly putrid, throw it away and begin again. Luckily, in our experience, this rarely happens.

What is sourdough, anyway?

Sourdough refers both to bread, and the starter used to make it. Sourdough starter begins with a combination of flour and liquid. The proportion and type of flour and liquid can vary dramatically, from a stiff starter made entirely with rye flour and water, to a liquid batter of milk and cornmeal, and everything in between.

Friendly bacteria (lactobacilli), present in our natural environment; and the wild yeast attracted to and living on flour (particularly whole grain flour) begin to work with one another when flour is mixed with warm water. The result: sourdough starter. These tiny living creatures (collectively called the sourdough’s microflora) generate byproducts that cause bread to rise and give it complex, rich flavor.

How does sourdough make bread rise?

Wild yeast is a tiny fungi. It exists all around us in varying degrees – in the air, settled on work surfaces, and in some of the ingredients you bake with: most importantly, flour.

Lactobacilli are also all around us. They have a wonderfully symbiotic relationship with wild yeast, the result of which is high-rising, delicious bread.

How does it all work?

Lactobacilli break down flour’s complex carbohydrates into simple sugars – exactly what yeast needs for food. The yeast, feeding on these simple sugars, produces carbon dioxide bubbles. The elastic wheat gluten in bread dough traps these carbon dioxide bubbles, causing the dough to expand as if it contained a million tiny balloons.

Where does sourdough bread’s flavor come from?

As byproducts of manufacturing simple sugars, lactobacilli produce flavorful organic acids: lactic acid, which adds a rich, mellow flavor to bread; and to a lesser degree over a longer period of time, acetic acid, which gives sourdough bread its sour tang.

To take a short deep dive here, there are two types of lactobacilli: homo-fermentative, which produces primarily milder-flavored lactic acid (think yogurt); and hetero-fermentative, which produces lactic acid, but also stronger – flavored acetic acid (think vinegar). Since homo-fermentative lactobacilli does well at room temperature, dough raised at room temperature will generally yield a milder-flavored bread. Hetero-fermentative lactobacilli prefers temperatures around 50 degrees F; so raising bread dough in a cooler spot will bring out its vinegary acidity.

By varying the hydration of your starter, and the temperature at which it’s fed; as well as the temperature and duration of a sourdough loaf’s rise, you can make sourdough bread that’s richly flavored, with barely a hint of sour; or one that’s truly mouth-puckering.