This article is all about how to make a sourdough starter from scratch! There’s something special about the process of making sourdough bread at home. The first step in your sourdough journey is to obtain an active sourdough starter. This can be done by receiving a starter from someone else or by creating your own. In this guide, I’ll walk you through the process of making your own sourdough starter from scratch.

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What is a Sourdough Starter

Sourdough starter is a mixture of flour and water that ferments over time to create beneficial bacteria by grabbing wild yeast from the air.

It is important to create good airflow for your sourdough starter, but not let it dry out. The yeast needs space to get in and do the fermentation, but you don’t want it drying out and getting crusty. However, I have a post on how to revive a dried starter should this happen to you.

Let’s get on with how to make it!

Ingredients

Flour: Whole wheat or rye flour is ideal for starting your sourdough culture due to its higher nutrient content and natural yeast presence. You can also use all-purpose flour to make your starter, though it may take longer to get it going. You can also do a combination of flours, which is what I suggest. Here is an article on the types of flour that can be used to create and maintain your starter. I usually go for organic flour.

Water: Use filtered or dechlorinated water to avoid any interference with the natural fermentation process. I use a Berkey filter system for my tap water, but if you have reverse osmosis in your home, that should work. If not, get some bottled water from your grocery store.

Equipment

Kitchen Scale
Glass jar
Wooden spatula is my preferred tool for stirring. You can also use silicone. Many suggest that metal is reactive and might interfere with the fermentation process, but I’ve never had an issue when stirring with a spoon.
You could use a proofing box if you’d like to regulate your room temperature (a dehydrator on super low could work here too, but don’t get it too hot, you don’t want to kill the bacteria)
Rubber band (I just pull them off my market veggies)

sourdough starter bubbling on a counter top

Day 1 | Create the Initial Mixture

Ingredients

25 grams of flour (I recommend half whole wheat flour and half bread flour)
25 grams filtered water

Instructions

In a glass container, mix the flour and water until well combined. The consistency should resemble a thick pancake batter.
Cover the container loosely with a cloth to allow air circulation. I prefer using a mason jar or Weck jar and setting the lid on top without screwing or sealing it. You want to capture yeast from the air, so if it’s airtight, that process won’t happen. The lid is primarily to keep dust and other particles out of the starter and not let it dry out. This is going to sit for 24 hours.

Note: You will want the temperature of the starter close to 75-80 degrees if possible. In the summer, this usually isn’t a big deal, but in the winter, it can be challenging. I usually put my starter in a turned-off oven with the light on. That environment produces just enough heat to keep the starter at a good temperature while fermenting. A word to the wise: leave a note on your oven so that it doesn’t accidentally get turned on by you or other members of your household!

Nowadays, I use a proofing box, but I don’t recommend getting any fancy or expensive equipment until you know this is something you’re going to enjoy doing.

Days 2-7 | Daily Feedings

Ingredients

25 grams of the existing mixture from the previous day
25 grams of flour
25 grams of water

Instructions

Each day, discard half of the existing mixture (by day 2, you should have 50 grams of the mixture left from day 1) and add more flour and water using a 1:1:1 ratio by weight
Stir the mixture well, ensuring there are no dry flour pockets.
Cover the container loosely and let it sit at room temperature, ideally between 75-80°F.
Ideally, feed once in the morning and once in the evening for best results. If you skip a feeding, that’s ok, but you will decelerate progress if you leave it without feedings for too long (it gets hungry!)

Signs of Sourdough Fermentation

As you progress through the daily feedings, you’ll start to notice changes in your mixture:

Bubbling: The starter will develop small bubbles, indicating that wild yeast is becoming active.
Rise and Fall: The mixture will rise after feedings and then gradually fall as the wild yeast consumes the flour.
Sour Aroma: The starter will develop a pleasant, slightly tangy smell.

By the end of the first week, your sourdough starter should be ready to use. If it isn’t, keep going; this process could take up to 3 weeks. If you haven’t done a lot of baking with yeast before, your kitchen may take longer to capture the wild yeasts, as they are scarce. The more you feed your starter, the more yeast activity you create, so keep going, even if it takes longer than you anticipated. If you are getting antsy, try feeding it primarily rye flour to speed up the process.

How To Tell If My Sourdough Starter Is Ready

Following the signs of fermentation above is a great way to know that the process is working. Once you have seen your starter rise to double after feedings consistently, it should be ready to use. You can also do the float test to see if it floats in water. If it does, it’s good to go. Just scoop out a bit of starter and put it in a glass of water to test.

How to Maintain Your Sourdough Starter

Once your sourdough starter is ready for baking, continue the daily feedings for a more stable and robust starter. If you’re not planning to bake every day, you can refrigerate the starter (make sure it’s airtight when going in the fridge) and feed it once a week or so (try to feed it at least twice per month, even if you aren’t baking with it much). If you bake regularly, just leave it on the counter and feed it once per day. I once left mine on the counter without feeding for several days, and it got extremely sour (smelled like alcohol) and very weak. I had to feed it rye flour consistently for a few days to get it back on track.

Sourdough starters are resilient, so don’t give up, even if the process seems slow or you forget about it for a while. You can always revive it. As long as it’s not moldy (fuzzy or pink), you’re good to go.

Tips and Troubleshooting

Patience is Key: Sourdough starters thrive on consistency. Be patient, and don’t be discouraged if progress seems slow initially.
Temperature of Your Starter Matters: Keep your starter at a consistent room temperature, ideally between 70°F and 75°F (21 °C and 24°C). When feeding, to speed up the activation process, try for around 75°F or slightly higher.
Adapt to Your Environment: Flour, water, and air temp can vary. Adjust the feeding ratio or frequency if needed.
Use Responsibly: When baking, always reserve a portion of your starter for future use. Never use the entire batch, or you’d have to start over.

Zero Waste

Sourdough is one of the best zero-waste traditional foods that you can invite into your kitchen. The discard can be used for many different recipes (see below), so nothing goes to waste.

Always use reusable everything.

When sourcing flour, ensure you’re getting it in paper bags or bags that can be reused. When you start getting the hang of it, milling your own flour is the best way to reduce waste and preserve as many nutrients as possible!

Your water source should be filtered, which means you may have to get some spring water from the grocery store. Many larger grocers offer a refillable faucet, which would be the better way to go here. I use a Berkey water filter. Reverse osmosis is also a great option.

Recipes

Here are a few of my go-to recipes. If a recipe doesn’t mention “discard,” it means you’ll need an active starter, that’s a starter that’s been recently fed, is bubbly, and has risen to its peak. Ideally, you want to use it when it’s just about to start falling again, that’s when it’s most active and ready to leaven the dough. But don’t worry too much if you miss the perfect timing. A healthy starter will still work even if it’s a little past peak.

On the other hand, discard is the portion of the starter you remove before feeding it again. It was once active, but since it hasn’t been fed, it’s no longer strong enough to make bread rise. That said, it’s still packed with flavor and great for things like pancakes, crackers, or quick breads. If your starter has been sitting flat for a few days, it probably needs a feeding or two to wake it up before using it in a full sourdough bread recipe.

Basic Sourdough Bread

Simple Focaccia Sourdough Sandwich Bread

Sourdough Discard Crackers

Sourdough Discard Granola

Sourdough Discard Brownies