How to Make Sourdough Starter from Scratch: 7-Day Beginner Guide

How to make sourdough starter is one of those things that sounds complicated until someone explains it properly. Two ingredients. Seven days. Five minutes a day.

That’s genuinely all it takes.

But here’s where most guides let you down: they assume you already know what “active” looks like, what “ready to bake” smells like Why your starter smelled like nail polish remover on day 4 and whether that’s fine (it’s). They skip the part where your kitchen is 65°F and the timeline needs to shift. They use words like “hydration ratio” without explaining what that means for a first-timer.

I’ve baked 2,973+ loaves of sourdough bread. I’ve taught thousands of home bakers. And my first starter almost didn’t make it because no one told me that the weird acetone smell on day 4 was completely normal yeast activity, not evidence that I’d destroyed something.

This guide is the one I wish I’d had. No assumed knowledge. No skipped steps. Let’s build your starter.

What You Need

You don’t need much. That’s one of the things I love about sourdough.

Equipment:

• A jar (a quart-size mason jar works great, or any clean glass container)
• A kitchen scale (this matters more than you think — eyeballing flour and water will slow down your progress)
• A rubber band or tape to mark the level after each feeding
• A kitchen towel or loose lid (not airtight — your starter needs to breathe)
• A spoon or spatula for mixing

Ingredients:

• All-purpose flour or whole wheat flour
• Water (filtered or left out overnight if your tap water is heavily chlorinated)

That’s it. No fancy starter cultures. No special equipment.

A note on flour: Whole wheat flour works faster because it has more wild yeast and bacteria naturally living in it. All-purpose is fine, expect day 1 through 3 to be quieter. Some people do a mix: whole wheat for the first 2 days, then all-purpose after that.

How a Sourdough Starter Works (The Short Version)

Wild yeast and beneficial bacteria exist on flour and in the air around you. When you mix flour and water and leave it out, those microorganisms start feeding on the starches in the flour. They produce carbon dioxide (which makes your bread rise) and lactic acid (which gives sourdough its flavor).

Feeding your starter means: removing some of it (the discard), adding fresh flour and water, and giving the microorganisms more food to work with.

Here’s the thing: your starter is a living thing. It needs consistent care for the first week. After that, it’s surprisingly forgiving.

The 7-Day Guide

Starting ratio: 1:1 flour to water by weight (50g flour : 50g water) Feed ratio (Day 3 onward): 1:1:1 (50g starter : 50g flour : 50g water)

Day 1 — The First Mix

Weigh 50g of whole wheat flour (or all-purpose) and 50g of room-temperature water into your clean jar. Mix until no dry flour remains. You want something that looks like thick pancake batter.

Cover loosely. Leave it at room temperature — ideally somewhere between 70-78°F (21-26°C). Your kitchen counter is fine.

What to expect: Nothing dramatic. Maybe a few tiny bubbles by the end of the day. Possibly nothing at all. Both are normal.

Mark the level with a rubber band so you can track any movement.

Day 2 — Waiting and Watching

Don’t feed it yet. Check on it.

You might see some bubbles. It might look a little puffed up. It might look exactly the same as yesterday. All of this is fine.

The bacteria are doing work you can’t see yet. Trust the process.

If you see any liquid pooling on top, that’s called “hooch.” It’s a sign your starter is hungry. Stir it back in. This is normal and not a problem.

Day 3 — First Discard and Feed

Now we start feeding.

1. Remove (discard) half the starter. So if you have 100g, dump out 50g.
2. Add 50g fresh flour and 50g water.
3. Stir well until fully combined.
4. Mark the new level with your rubber band.
5. Cover loosely and leave at room temperature.

Where does the discard go? Down the sink for now. Once your starter is active and mature, sourdough discard is incredible in pancakes, crackers, and pizza dough. This week, discard it.

What to expect today: More bubbles than yesterday. Maybe some expansion above your rubber band mark. Your starter should start smelling noticeably different — probably slightly tangy or sour.

Day 4 — This Is the Weird Day

Day 4 is when things get unpredictable, and when most beginners start to panic.

Your starter might smell like cheese. Or nail polish remover. Or beer. Maybe a combination of all three.

Don’t panic. This is completely normal.

The acetone/nail polish smell comes from acetic acid production. It’s part of the fermentation process. It will mellow out as your starter matures.

Feed again today:

1. Discard down to 50g.
2. Add 50g flour and 50g water.
3. Stir, mark, cover.

Day 5 — Signs of Life

By day 5, most starters are showing real activity. you’ll see:

• Bubbles throughout the starter, not just on top
• Clear rise between feedings (check your rubber band mark — has it gone up since you fed it?)
• A more pleasant, yogurt-like sour smell replacing the harsher smell from day 4

Feed twice today if your starter is active. When it smells good and rises within 4-6 hours of feeding, it’s ready for twice-daily feedings.

1. Morning feed: discard to 50g, add 50g flour + 50g water.
2. Evening feed (12 hours later): repeat.

If your starter is still slow and flat, stick to once a day and give it more time. A cold kitchen (below 68°F) will slow everything down. Move your jar to a warmer spot — on top of the refrigerator, or near your oven when it’s been on.

Day 6 — Building Consistency

By now you’ll be seeing consistent rise and fall between feedings. Your starter should:

• Rise to roughly double (or close to it) after each feeding
• Fall back down within 8-12 hours
• Smell pleasantly sour, like tangy yogurt or vinegar, not harsh or cheesy

Continue twice-daily feedings. Discard to 50g before each feed.

Day 7 — Is It Ready?

Here’s how to know your starter is ready to bake with:

The float test: Drop a small spoonful of starter into a glass of water. If it floats, it’s full of bubbles and ready to use. If it sinks, give it another day or two of feedings.

The rise test: Feed your starter and mark the level. Check every 2 hours. If it doubles within 4-8 hours and smells pleasantly sour, it’s ready.

The smell test: It should smell like tangy yogurt, light vinegar, or sourdough bread. Not harsh, not like chemicals.

If you’re not there yet on day 7, that’s okay. Some starters take 10-14 days, especially in cold kitchens or with all-purpose flour only. Keep feeding. It will get there.

Once Your Starter Is Ready

Your starter is now ready to bake with. Here’s what you do next:

• For baking: Feed your starter 4-8 hours before you plan to use it, so it’s at its peak activity.
• For maintenance: Keep it in the fridge and feed it once a week if you’re not baking. Take it out, let it come to room temp, feed, wait for peak activity, then put it back.
• For storage: Covered in the fridge, a healthy starter lasts months between feedings (though once a week is better for consistent performance).

Common Problems and What to Do

My starter isn’t bubbling at all after 3 days. Use warmer water (80-85°F). Move your jar somewhere warmer. Switch to whole wheat flour for 2-3 feedings, then switch back. Chlorinated tap water can slow things down — try filtered water or water left out overnight.

It smells really bad — like vomit or feet. This usually means the bacteria have overtaken the yeast. Discard all but a tablespoon, add fresh flour and water, and feed more frequently for 2 days. This usually resolves it.

There’s pink or orange streaks in my starter. Stop. Do not use this starter. Pink or orange coloring means contamination with unwanted bacteria. Clean your jar thoroughly, start over. This is rare, but it happens.

It doubles but then falls flat really fast. Your starter is probably overripe when you use it. Use it closer to peak — right when it’s domed on top and hasn’t started to fall yet. Time your feeding so peak hits when you need it.

My kitchen is cold. Will this even work? Yes, it’ll just take longer. A starter in a 65°F kitchen may take 10-12 days to become fully active. Be patient and consistent. You can speed things up by placing the jar in your oven with just the oven light on (not the oven itself — just the light) to get about 75-78°F.

The Part Nobody Wants to Tell You

Here’s the honest truth: some people’s starters take 14 days. Some take 7. Yours might be reliably doubling by day 5, or it might be sluggish through day 10.

None of that means you’re doing it wrong.

The variables are: your kitchen temperature, your flour, your water, and the specific wild yeasts in your local environment. That’s why every starter is different. Mine smelled completely terrible until day 8. Then it was perfect and I’ve been using the same starter for years.

Trust me: if you follow the steps above consistently, you’ll have a starter that works.

Want This Process Walked Through With You?

Building a starter from instructions is one thing. Having someone walk you through exactly what to look for, day by day, with video, is different.

That’s what Bread ASAP is.

I made Bread ASAP because most people making their first sourdough starter have questions at 9pm on day 4 when their starter smells weird and looks flat and they’re not sure if they should keep going. Written guides can’t answer those in real time. Video can.

Bread ASAP includes:

• Step-by-step video for every stage of starter building
• A daily checklist for each of the 7 days
• A troubleshooting section for every common problem (including the day 4 smell)
• The first loaf method — so you know exactly what to do once your starter is ready
• Access to the baker community for questions as they come up

This is the guided version of everything on this site. If you want to go through the process with support, rather than reading and hoping, Bread ASAP is the path.

You’ve already proven you’re serious by reading this far. The next step is just a click.

Get Bread ASAP — $47

If you’re not ready for that yet, that’s completely fine. Start with the 7-day guide above. It works. I’ve watched thousands of bakers use it.

And if you want to skip starter-building entirely — a completely valid choice — you can get a live, tested, ready-to-bake Proven Starter shipped to your door for $19.99. No building. No waiting. Add flour on day one.

More to Explore

• How to Know When Sourdough Starter Is Ready — Visual cues that your starter is bake-ready.
• Easy Sourdough Bread Recipe for Beginners — Your first loaf after your starter is ready.
• Sourdough Discard Pancakes — Put that day 3-6 discard to work.
• Sourdough Bread Baking Timeline — Plan your first bake around your real schedule.
• Bread ASAP ($47) — Guided video for your first starter + first loaf.

Drop a comment below — I read every one.

Happy baking — Roselle