Sourdough Starter Basics: How to Make, Feed and Keep a Starter Alive Without Stress

Sourdough has become one of the most popular home baking projects of recent years, and for good reason. A loaf made with a homemade starter has a crackling crust, an open, chewy crumb and a complex, gently tangy flavor that commercial yeast cannot match. At the heart of every sourdough loaf is the starter: a simple mixture of flour and water that captures wild yeasts and bacteria and keeps them alive with regular feeding. Creating a starter can seem mysterious, and many beginners worry about doing it wrong or "killing" it. In reality, starters are remarkably resilient. This guide explains what a starter is, how to make one from scratch, how to care for it and how to fix common problems.

What is a sourdough starter?

A sourdough starter is a living culture of wild yeasts and lactic acid bacteria. These microorganisms are naturally present in flour, in the air and on our hands. When flour and water are mixed and left at room temperature, they begin to grow. The yeasts produce carbon dioxide gas, which makes dough rise, and the bacteria produce lactic and acetic acids, which give sourdough its characteristic tang and help keep the bread fresh longer.

The yeasts and bacteria in a starter live together in a stable community. The acids they produce make the environment hostile to many unwanted microbes, which is why a healthy starter can be kept for years, sometimes decades.

What you need

• Flour: Whole-grain flours such as whole wheat or rye contain more nutrients and naturally occurring microbes, so they help a new starter become active faster. Many bakers begin with whole wheat or rye flour and later switch to all-purpose or bread flour. Unbleached flour is preferred.
• Water: Use lukewarm water. If your tap water is heavily chlorinated, let it stand uncovered for a few hours or use filtered water.
• A jar: A glass jar of at least 1 quart (1 liter) with a loose-fitting lid. Glass lets you see the bubbles and the rise.
• A kitchen scale: Weighing flour and water makes the process consistent.
• A rubber band or marker to mark the level of the starter after feeding, so you can see how much it rises.

Making a starter: a day-by-day plan

The timing varies with temperature, flour and environment, but this plan works for most kitchens. A warm spot around 75 to 80 °F (24 to 27 °C) speeds things up.

Day 1: Mix 50 g whole wheat or rye flour with 50 g lukewarm water in a clean jar. Stir well until no dry flour remains. Cover loosely and leave at room temperature.

Day 2: You may see a few bubbles or nothing at all. Both are normal. Stir, cover and wait.

Day 3: Discard about half of the starter. Add 50 g flour and 50 g water. Stir well. Discarding prevents the starter from growing too large and keeps the ratio of food to microbes healthy.

Days 4 to 7: Feed once or twice a day: discard all but about 50 g of starter, then add 50 g flour and 50 g water. You can switch to all-purpose or bread flour, or keep using a mix.

A common surprise: Around days 2 to 4, many starters suddenly bubble vigorously and may double in size, then seem to go quiet. This early activity is often caused by bacteria that thrive at the beginning and then die off as the starter becomes more acidic. It does not mean the starter has failed. Keep feeding regularly.

Days 7 to 14: The starter gradually becomes more predictable. It should rise and fall on a regular schedule after each feeding, smell pleasantly sour or yeasty and look bubbly throughout.

Some starters are ready in a week; others take two weeks or more, especially in a cool kitchen. Patience is the most important ingredient.

How to tell when your starter is ready

A starter is ready to bake with when it reliably:

• Doubles in volume within about 4 to 8 hours after feeding at room temperature.
• Has bubbles throughout, not just on the surface.
• Smells pleasant, tangy and yeasty, somewhat like yogurt, beer or apples.
• Has a domed top at its peak, which then begins to fall as the yeast runs out of food.

The float test, dropping a spoonful of starter into water to see if it floats, is often recommended, but it is not completely reliable. Whole-grain starters or very liquid starters may sink even when active. Rising and smell are better indicators.

Feeding ratios explained

Bakers describe feeding ratios as starter to flour to water by weight. A ratio of 1:1:1 means equal weights of starter, flour and water, for example 50 g starter, 50 g flour and 50 g water. This is a good everyday ratio.

• Lower ratios like 1:1:1 feed the starter less food, so it peaks faster, often in 4 to 6 hours.
• Higher ratios like 1:5:5 give the starter more food, so it takes longer to peak, perhaps 8 to 12 hours. This is useful if you want to feed it in the evening and bake in the morning.

Most starters are kept at 100 percent hydration, meaning equal weights of flour and water. Stiffer starters with less water ferment more slowly and develop a tangier flavor; looser starters are faster and milder.

Keeping a starter in the refrigerator

If you do not bake every day, you do not need to feed your starter every day. Once it is well established, after a few weeks of regular feeding, you can store it in the refrigerator:

1. Feed the starter as usual.
2. Let it sit at room temperature for an hour or two until it starts to bubble.
3. Cover the jar and refrigerate it.
4. Feed it about once a week.

The cold slows down the microorganisms significantly. When you want to bake, take the starter out a day or two in advance and feed it once or twice at room temperature until it is active and doubling reliably again.

Hooch, mold and other worries

• Hooch: A grayish or brownish liquid on top of the starter is called hooch. It is alcohol produced by hungry yeast and means the starter needs feeding. Pour it off for a milder flavor or stir it in for a tangier one, then feed.
• Strong smells: A starter may smell like nail polish remover, vinegar or even gym socks when hungry. This is usually a sign it needs feeding more often. Regular feeding restores a pleasant smell.
• Mold: Fuzzy spots, especially pink, orange or green, or streaks of pink or orange in the starter are signs of contamination. In that case, the safest choice is to throw the starter away and start again.

A dried crust on top is not mold. Remove it and feed the starter underneath.

Reviving a sluggish starter

If your starter has stopped rising or seems weak:

• Move it somewhere warmer. Temperatures below 68 °F (20 °C) slow fermentation significantly.
• Feed it more regularly at room temperature, once or twice a day, for several days.
• Add whole-grain flour. A tablespoon or two of whole wheat or rye flour in each feeding gives the microbes extra nutrients.
• Check your water. Heavily chlorinated water can slow activity.
• Use a higher feeding ratio for a few days, such as 1:2:2, to dilute the acids.

Most sluggish starters recover within a few days of consistent care.

Using sourdough discard

When you feed your starter, you remove part of it. This "discard" does not need to go to waste. Since it is not at its peak, it is not strong enough to raise bread on its own, but it adds flavor to many recipes:

• Pancakes and waffles.
• Crackers.
• Flatbreads and pizza dough combined with commercial yeast.
• Muffins, banana bread and quick breads.
• Pasta dough or fritters.

Store discard in a covered jar in the refrigerator for up to about a week, and use it in recipes as needed.

Sharing a starter

One of the joys of sourdough is sharing. Friends and neighbors with established starters can give you a spoonful to get started immediately. You can also dry a starter to store or send it: spread a thin layer on parchment paper, let it dry completely, break it into flakes and store them in an airtight jar. To revive it, mix the flakes with water and flour and feed regularly for a few days.

Frequently asked questions

How long does it take to make a starter? Usually one to two weeks, sometimes longer in a cool kitchen. Consistency in feeding and a warm spot help.

Do I have to throw away half of my starter at each feeding? Discarding keeps the starter manageable and maintains a healthy balance of food and acidity. You can keep the discard in the fridge and use it for pancakes, crackers and other recipes.

Can I use all-purpose flour for a starter? Yes. Whole-grain flours help a new starter get going faster, but an established starter thrives on all-purpose or bread flour.

What if I forget to feed my starter? Most established starters survive several weeks in the refrigerator without feeding. Pour off any hooch and feed it a few times at room temperature to bring it back to strength.

Why does my starter smell like acetone? It is hungry. Feed it more often or with a higher ratio of fresh flour and water, and the smell will improve.

The bottom line

A sourdough starter is simply flour and water that capture and grow wild yeasts and bacteria. Mix equal weights of whole-grain flour and lukewarm water, discard and feed regularly, and keep the jar in a warm spot. Within one to two weeks, your starter should double reliably after feeding and smell pleasantly sour. Store it in the refrigerator and feed it weekly when you bake less often, revive it with warmth and regular feeding if it slows down, and use the discard in pancakes and crackers. With a little patience, your starter will become a lasting companion in your kitchen.