How To Make a Sourdough Starter

Making a sourdough starter takes time, not much effort. With just flour, water, and a little patience, you can create your own natural starter in about one to two weeks.

My first starter didn’t last very long, but during my second attempt I documented everything: what I observed, the mistakes I made, and, most importantly, what actually worked. I’ve combined all of those experiences into this comprehensive guide.

Table of Contents

• What is a sourdough starter?
• A few tips before you begin
• What you’ll need
• Which flour should you use?
• What temperature is ideal?
• The different stages of a sourdough starter
• When is your starter ready to bake with?
• From feeding your starter to baking-ready (with photos)
• Feeding your starter different ratios
• How to store and maintain your sourdough starter
• What can you do with discard?
• Frequently asked questions
• Sourdough starter recipe

What Is a Sourdough Starter?

In short, a sourdough starter is a mixture of flour and water that naturally cultivates wild yeast and lactic acid bacteria. These natural yeasts make bread rise, so there’s no need for commercial yeast.

The beauty of it is that you only need two ingredients: flour and water. Nature takes care of the rest. By feeding your starter fresh flour and water every day, you’ll gradually develop an active culture that can be used to bake incredible sourdough bread.

On average, it takes about one to two weeks for a starter to become strong enough for baking. For some people it happens faster, while for others it takes a little longer. Factors like temperature, the type of flour you use, and a bit of luck all play a role.

And perhaps the most important thing to know before you start: you can’t rush a sourdough starter. Patience really is part of the recipe.

What You’ll Need

One of the best things about making a sourdough starter is how little you actually need. It’s an easy project to get started with.

Ingredients and tools

• Rye flour and/or rye meal
• Lukewarm water (about 25°C/82˚F)
• Equipment
• Glass jar
• Kitchen scale
• Silicone spatula or wooden spoon
• Rubber band
• Thermometer (optional, but helpful if you’re unsure about water temperature)

There are also convenient sourdough starter kits that include everything you need. I really liked using a kit with a glass jar and a temperature strip attached to the outside. It made it much easier to monitor the starter while it was developing.

If you’re planning to bake sourdough bread as well, you may prefer a more complete starter kit that includes additional baking essentials.

TIP: During the winter months, a heating plate (or heating mat) was an absolute game changer for me. My kitchen was simply too cold to keep the starter active. I still pull it out every winter. It’s certainly not essential, but it can noticeably speed up the process.

Which Flour Should You Use?

I started my sourdough starter using whole rye flour and later began feeding it with a combination of whole rye flour and light rye flour. That’s still what I use today, usually a mix of both, though sometimes I feed it with only light rye flour.

Technically, you can make a starter with all-purpose flour, but it usually takes longer to become active. Whole wheat flour is already a better option. Still, I recommend using rye flour whenever possible because it’s richer in nutrients, allowing the starter to develop more quickly.

• Whole Rye Flour. Whole rye flour contains lots of nutrients, which helps a starter become active quickly. Starters made with only whole rye flour often have a thicker consistency, and that’s perfectly normal.
• Light Rye Flour. Light rye flour works much like whole rye flour and is another excellent choice. It often produces a slightly lighter, airier starter with finer bubbles.
• All-Purpose Flour. All-purpose flour can also be used to make a sourdough starter, but because it contains fewer nutrients, it usually takes longer for the culture to become fully active.
• Whole Wheat Flour. Whole wheat flour is rich in nutrients and generally produces an active starter fairly quickly. While rye often gives even faster results, whole wheat is an excellent alternative if you prefer not to use rye.

My Preference. These days I usually feed my starter with a combination of whole rye flour and light rye flour. The whole rye keeps the starter vigorous, while the light rye tends to produce a lighter texture with lots of small bubbles. That’s why I generally use a little more light rye flour than whole rye flour.

What Temperature Is Ideal?

Temperature plays a major role in sourdough baking. It affects not only how quickly your starter develops but also how long your dough needs to ferment.

I started my first sourdough starter during the winter. During the day, my kitchen stayed around 19–20°C, but at night it dropped to about 15°C. You can absolutely make a starter at those temperatures, but the process usually takes a bit longer. Eventually, I placed my starter on a seedling heat mat and noticed it became much more active.

In my experience:

• 22–24°C (71.6 – 75.2˚F) is ideal.
• 18–20°C (64.4 – 68˚F) also works well, but expect the process to move more slowly, especially if your home cools down overnight.

TIP: Don’t have a warm spot in your house? Try draping a clean kitchen towel loosely over the jar. It can help keep the temperature a little more stable. My favorite solution, though, is still a seedling heat mat. I use mine every winter whenever the house gets chilly.

The Different Stages of a Sourdough Starter

No two sourdough starters develop exactly the same way. One may be ready to bake with after a week, while another might need two or even three weeks. Think of the stages below as a general guide rather than a strict timeline.

1. The first burst of activity. During the first few days, your starter may suddenly grow quite a bit and develop lots of tiny bubbles. This is completely normal. However, this initial burst of activity isn’t stable yet, so simply continue feeding it on your regular schedule.
2. The quiet phase. After that first burst, it’s common for the activity to slow down considerably. Your starter is busy developing a strong, stable culture. Stay patient and pay attention to the small bubbles and the fresh, slightly tangy aroma rather than how much it rises.
3. Growing stronger. After about a week – sometimes sooner, sometimes later – you’ll usually notice the activity becoming more consistent. The smell gradually changes from slightly musty to pleasantly tangy, similar to yogurt, and you’ll start seeing more bubbles throughout the starter.
4. Ready to Bake. Eventually, your starter will respond predictably after each feeding. It will double, or even more, in volume, become full of bubbles, and stay active for several hours. Later in this guide, I’ll explain exactly how to recognize when it’s ready for baking.

When Is Your Starter Ready to Bake With?

Once your starter has matured, there are a few signs that tell you it’s ready to use. Your starter is ready when it:

• Has a fresh, pleasantly tangy smell without any harsh or unpleasant odors.
• Is filled with bubbles from top to bottom.
• Has at least doubled in size. My own starter often triples in volume at its peak.
• Has a gently domed surface.

When your starter matches this description, it’s at – or very close to – its peak activity and ready for baking. In fact, you can usually bake successfully just before it reaches its absolute peak as well.

Has your starter already begun to fall? That simply means it’s past its peak. It’s still often perfectly usable for baking, but I personally get the most consistent results when I use it at, or just before, its highest point.

TIP: Many bakers use the float test by dropping a small spoonful of starter into a glass of water. If it floats, it’s often considered a sign that the starter contains enough trapped air. Personally, I rarely use this test. Instead, I rely on observing my starter’s behavior. Over time, you’ll naturally learn to recognize when your own starter is ready.

From Feeding to Baking-Ready

To give you a better idea of what this looks like, I photographed my own starter from immediately after feeding until it was ready to bake with. Your starter may not follow exactly the same timeline, since temperature and other conditions affect how quickly it develops.

How Many Hours After Feeding Is a Starter Ready to Bake With?

If you feed your starter every 24 hours, you’re usually feeding it once it’s hungry and no longer very active. That’s not the ideal moment to start baking.

After a 1:1:1 feeding, my own starter reaches its peak after about 3 to 5 hours, depending on the temperature in my house.

As you become more familiar with your starter, you’ll discover that changing the feeding ratio allows you to plan more precisely when it will peak. I often feed mine in the evening so it’s perfectly active first thing the next morning when I’m ready to bake.

TIP: If you’ve weighed out part of your starter for a bread recipe, simply leave the remaining starter in the jar. Feed it again once it becomes hungry, which is usually about 24 hours after its previous feeding.

Feeding Your Starter Using Different Ratios

As you become more familiar with your sourdough starter, you’ll find that changing the feeding ratio makes it easier to plan when your starter will be at its peak. Here’s a general idea of how the most common ratios work:

• 1:1:1 Feeding. This is the standard feeding ratio and a great choice if you feed your starter every day. With this ratio, my starter usually reaches its peak after about 3 to 5 hours.
• 1:2:2 Feeding. With a 1:2:2 feeding, you’re giving your starter twice as much fresh flour and water. As a result, it takes longer to reach peak activity, usually around 6 to 8 hours.
• 1:5:5 Feeding. This ratio is ideal if you like to plan ahead. Your starter will generally need 10 to 12 hours, or even longer, to reach its peak, depending on the temperature in your home.

Think of these times as general guidelines rather than fixed rules. Room temperature, the strength of your starter, and the type of flour you use all influence how quickly it becomes active. The more often you bake, the easier it becomes to recognize exactly when your starter is ready.

Storing and Maintaining Your Sourdough Starter

When you’re first creating a starter, you’ll feed it every day. Once it’s mature and healthy, caring for it becomes much easier.

• If you bake sourdough regularly, you can keep your starter at room temperature and feed it daily.
• If you’re more like me and only bake occasionally, storing it in the refrigerator is much more convenient.

I keep my starter covered in the refrigerator and usually feed it once every 2 to 3 weeks, whenever I know I’ll be baking soon. One or two days before baking, I take it out of the refrigerator, feed it again, and wait until it’s nice and active.

I like to refrigerate my starter shortly after feeding, when it’s clearly active but just before it reaches its peak. That way it goes into the refrigerator strong and stays healthy while it’s resting.

What Can You Do with Discard?

Every time you feed your starter, you’ll remove a portion before adding fresh flour and water. The part you remove is called discard.

During the first few days of creating a new starter, it’s best to throw the discard away. At that stage, the starter isn’t stable enough to bake with.

Once your starter has become established, you can save the discard instead. Simply transfer it to a container and store it in the refrigerator.

Discard is incredibly versatile and can be used in all kinds of recipes. One of my personal favorites is sourdough crackers, and I’ll be sharing that recipe very soon. It’s also wonderful in waffles, pancakes, muffins, and many other baked goods.

You can store discard in an airtight container in the refrigerator for about 1 to 2 weeks.

How to minimize discard?

I don’t mind having some discard on hand because I love making crackers with it. But with a little planning, you can reduce waste significantly.

For example, if your recipe calls for 100 grams of active starter, you could feed:

• 40 grams starter
• 40 grams water
• 40 grams flour

(using a 1:1:1 ratio)

That gives you 120 grams of active starter: 100 grams for your recipe and 20 grams left to keep your starter going or return to the refrigerator.

The nice thing is that you don’t need much starter to build it back up. I’ve even fed my starter when there was only about 1 teaspoon left in the jar. Using a 1:10:10 feeding ratio, it grew back into a healthy, active starter without any problems.