Starting a sourdough culture from scratch is one of the most rewarding things you can do in the kitchen – and it’s simpler than it sounds! With just flour, water, and a little daily rhythm, you can grow something alive and nourishing right on your countertop.
Using freshly milled flour makes the process even more vibrant. Whole grains are full of wild yeast and nutrients that give your starter a strong, healthy start. No special equipment, no guesswork – just a quiet routine that builds day by day.
Whether you’re brand new to sourdough or starting fresh with home-milled grain, this guide will walk you through each step. You’ve got everything you need to begin.
What Is a Sourdough Starter?
A sourdough starter is simply a mixture of flour and water, left at room temperature to begin fermenting. Over time, wild yeast and beneficial bacteria – already present in your flour and the air – start to grow and multiply.
With a few days of consistent feeding, this humble mixture becomes strong enough to leaven bread on its own – no commercial yeast required.
That’s the beauty of sourdough. Rather than opening a packet, you’re cultivating your own natural yeast – a living ingredient you can feed, tend, and use again and again. Once active, your starter can become the base for bread, pancakes, pizza dough, and more.
If you’ve never done this before, don’t worry. We will keep it simple, and by the end of the week, you’ll have your own homemade starter ready to use.
Why Use Freshly Milled Flour?
Freshly milled flour brings something special to a sourdough starter – life.
When you grind whole grains at home, you’re working with flour that’s full of natural yeast, nutrients, and oils. Nothing has been stripped away, sifted out, or sitting on a shelf for months. It’s alive, and that liveliness helps your starter grow strong and active from the beginning.
Beyond the yeast, freshly milled flour carries the full character of the grain – earthy, sweet, complex. It creates a deeper flavor in your bread and a richer connection to the process. You know where it came from. You ground it yourself. There’s intention in that, and it shows up in every loaf.
It’s also a practical choice. Using the whole grain means nothing goes to waste, and your starter gets the full spectrum of nourishment it needs to thrive.
Ingredients
Here’s what to gather before you get started:
- Freshly milled whole grain flour (Rye wheat berries are ideal, but any hard wheat works)
- Filtered water, room temp
Supplies
- A clean glass jar or food-safe container (At least pint-sized, but a quart jar gives more room for rising.)
- Spoon or silicone spatula (For mixing your flour and water.)
- Breathable lid or clean cloth and rubber band (You want to keep dust out but still let the starter breathe.)
- Jar marker or rubber band (optional) (Helpful for marking how much the starter rises.)
- Kitchen scale (It makes feeding more accurate.)
- Digital Thermometer (For checking water temp.)
That’s it. Once everything’s ready, you’ll be all set to start building a strong, healthy starter!
Day-by-Day Sourdough Starter Timeline
This method takes 10 days, depending on your flour, temperature, and patience. Just take it one day at a time and enjoy growing your new culture.
Day 1:
To start your sourdough starter, get a clean glass jar and mix 50 grams of freshly milled flour with 50 grams of room temperature filtered water. Rye flour is great because it’s very active and helps things get going quickly. But any kind of hard wheat flour will work just fine.
Now, you might be wondering – why measure in grams instead of using cups or tablespoons?
Grams offer precision. Freshly milled flour can vary in density depending on how it’s ground, so measuring by weight ensures you’re feeding your starter equal parts flour and water by mass, not just volume. This balance helps your starter grow steadily and consistently.
Stir the mixture until it’s smooth and well combined. The texture might feel slightly slick or oily – that’s perfectly normal. Fresh flour still contains all the oils from the bran and germ, which adds richness to the mix.
Scrape down the sides and cover the jar with something breathable, like a clean cloth secured with a rubber band. Set it in a warm spot out of direct sunlight, and let it rest for 24 hours while the wild yeast and beneficial bacteria begin their quiet work.
Day 2:
By the second day, you may already see a few encouraging signs – tiny bubbles, a slight rise, or a soft puffiness in the jar. This means the wild yeast and beneficial bacteria are beginning to multiply. It’s subtle, but it’s working.
Freshly milled flour includes the whole grain (bran, germ, and endosperm) so it tends to absorb more water than refined flour. If the surface looks a bit dry or thick, don’t hesitate to add a splash of extra water to keep the mixture pliable.
Today, we begin regular feedings. Start by discarding about half the starter (around 50 grams). This keeps the total volume manageable and prevents overcrowding. Don’t worry – “discard” doesn’t mean waste. You can set it aside for pancakes, muffins, or even to share with a friend.
Feed the remaining starter with 50 grams of fresh flour and 50 grams of water – plus a little extra (about 5 grams of water) to keep things hydrated. Stir until smooth, cover loosely, and let it rest in its warm spot once again.
Your starter is waking up.
Day 3:
By the third day, your starter should be showing clear signs of life: a flurry of bubbles, a bit of rise, and perhaps even a collapse as the gases release. These are all good things – evidence that the wild yeast and bacteria are growing stronger.
You may also notice a sour or off-putting smell, sometimes reminiscent of cheese or even old socks. Don’t be alarmed. This stage is completely normal. As different strains of bacteria come and go, the aroma will shift. Give it time – it will mellow and balance as your starter matures.
Keep going with your routine: discard about half, then feed with equal parts starter, freshly milled flour, and water (50 grams each), plus your usual hydration boost – an extra 5 grams of water. Stir well, cover loosely, and return it to its warm resting place.
Your starter is doing just what it’s meant to do.
Day 4:
You’ll likely still see steady activity – bubbling, rising, and falling – but your starter may not be consistent just yet. That’s completely normal. The rhythm can feel a little unpredictable in these early days, and the smell might still be strong or unfamiliar.
Freshly milled flour brings in more microbial diversity, which is a gift in the long run. It helps your starter develop deeper flavor and greater resilience but it can also mean a slightly longer path to stability.
Stay the course with your daily rhythm: discard half, then feed with 50 grams of fresh flour and 50 grams of water. Add a splash more water if it seems stiff or dry; the texture should be soft, like thick batter.
Your starter is still finding its footing – but every feeding brings it closer to maturity.
Days 5:
By now, you may notice your starter rising and falling more predictably – perhaps even doubling in size a few hours after feeding. This is a strong sign that your wild yeast is active and well-fed.
The aroma should begin to shift, too – less sharp, more pleasantly tangy. And when you stir it, the texture may feel smoother and a bit stretchy, a hint of the structure it will give your bread.
Stick with your daily rhythm: discard half, feed with 50 grams of fresh flour and 50 grams of water, and add that extra splash (about 5 grams) if it needs help staying soft and hydrated.
Your starter is nearly ready. Just a little more consistency, and it will be strong enough to bake with.
Day 6:
At this stage, your starter should be bubbly, active, and noticeably improved in aroma. The smell will likely be pleasantly sour and bready, rather than sharp or off. If it’s doubling quickly and rising and falling within several hours, that’s your cue: it’s ready for more frequent feedings.
Starting today, shift to feeding every 12 hours – once in the morning and once in the evening. Continue with your 1:1:1 ratio: 50 grams of starter, 50 grams of freshly milled flour, and 50 grams of water. Add an extra 5 grams of water if it needs help staying soft and pliable.
If you catch a whiff of vinegar or something like nail polish remover, that’s a sign your starter is getting too hungry between feedings. The extra feeding will help keep it balanced and thriving.
You’re almost there.
Days 7 to 9:
Over the next few days, your starter will continue to grow stronger and more reliable. With twice-daily feedings, you’ll likely notice a steady rhythm emerge – rising, peaking, and gently falling between feedings, like a quiet breath.
The aroma should now be mild and pleasantly tangy, and you’ll see bubbles dispersed throughout the mixture, not just collecting at the top or bottom. When you stir it, the texture will feel light, airy, and a bit elastic – another sign that the yeast is active and well-fed.
Continue your 12-hour feeding schedule using the same flour. Avoid switching flours at this stage – consistency helps your culture stabilize and settle into its full strength.
Each feeding brings it closer to becoming a dependable part of your kitchen rhythm.
Day 10:
By day ten, your sourdough starter should be fully active and ready to use. It should rise predictably – doubling in size within hours of feeding – with bubbles visible throughout the jar, not just on the surface.
The smell should be clean and pleasantly sour, with a fresh, yeasty brightness that signals it’s ready for baking.
If you’ve come this far, you’ve cultivated something alive – something that can now rise loaves, nourish your family, and carry on for years with just a bit of ongoing care.
How to Know When Your Starter Is Ready
By day ten (sometimes a bit sooner, sometimes later), you should have a starter that’s strong, bubbly, and pleasant-smelling. Here are the main signs it’s ready to use:
- It doubles in size within 4 to 6 hours of feeding
- It has bubbles throughout, not just on the surface or bottom
- It smells clean and sour, like yogurt, citrus, or good sourdough bread
If you’re not seeing all these signs yet, keep feeding it every 12 hours for another day or two. Some starters just need a bit more time, especially depending on your kitchen temperature and flour type.
How to Maintain Your Starter After It’s Mature
Once your starter is strong and ready to bake with, you can shift into a maintenance routine. Here’s how to keep it happy, whether you’re baking every day or once a week:
- If baking daily: Keep your starter on the counter and continue feeding it every 12 to 24 hours, depending on how quickly it rises and falls. Stick with the 1:1:1 ratio by weight.
- If baking occasionally: Store your starter in the fridge. Feed it, let it sit at room temp for an hour, then refrigerate. You’ll only need to feed it once a week. Before baking, take it out, feed it twice a day for 1–2 days to wake it back up.
- Always discard before feeding. This keeps the starter strong, balanced, and not too acidic. You don’t have to throw the discard away – save it for recipes!
What to Do With Your Discard
Discard doesn’t mean waste! While you do need to remove a portion of the starter before feeding to keep the microbial balance in check, you can absolutely use that “discard” in recipes. Here are a few favorites:
- Pancakes or waffles
- Cookies or quick breads
- Crackers or flatbreads
- Sourdough pasta
- Compost (if you’ve really got too much to use)
Just make sure the discard isn’t too sour or neglected if you’re planning to eat it.
Common Questions & Troubleshooting
Sourdough is a living culture, and like anything alive, it doesn’t always follow a perfect script. Here are a few common concerns – and some gentle guidance to help you stay the course.
1. “My starter smells bad – like cheese or nail polish.”
This is very common in the early days. A strong or unusual smell usually means the bacteria are actively establishing themselves. As long as it’s not truly rotten or moldy, those sharp, sour, or even funky aromas are part of the process. With consistent feeding, the scent will mellow into something fresh and pleasantly tangy.
2. “There’s liquid on top. Is that bad?”
That liquid is called hooch, and it simply means your starter is hungry. It’s not harmful – just a sign it’s ready for its next meal. You can stir it back in or pour it off before feeding. If it happens often, consider feeding a little more frequently.
3. “It’s not bubbling much.”
Freshly milled flour starters can take a little longer to stabilize. Make sure you’re using warm (not cold) water, and keep the jar in a cozy spot – around 70–75°F is ideal. Stay consistent with your feedings. If you need a boost, a bit of rye flour can help wake things up.
4. “I forgot to feed it. Is it ruined?”
Likely not. Sourdough starters are more forgiving than they seem. If it’s been a day or two, just pick back up where you left off. If it’s been longer, give it a few regular feedings to rebuild strength. In most cases, it will bounce back.
Remember – this process is part science, part instinct. Trust your senses, stay steady, and don’t be afraid to start again if you need to.
Start Your Starter – And Stick With It
Making a sourdough starter from freshly milled flour takes a bit of patience, but it’s one of the most satisfying DIYs in the kitchen.
You’re growing something alive, something nourishing, and something you can use for years to come.
So don’t stress if it’s not perfect right away. Just keep feeding, keep observing, and give it time.
Before long, you’ll have a wild, living culture that smells amazing, bakes beautifully, and came from your own two hands and a jar of flour.
