How to Make a Sourdough Starter from Scratch
Just flour and water — no yeast, no special equipment, no discard drama. Here’s the simple 7-day method that turns a jar on your counter into a bubbly, living starter ready to bake real bread.
📌 Starting today? Pin this guide so you have the day-by-day feeding schedule right on your phone all week.
A living starter is easier than it looks
If you’ve been wanting to make a sourdough starter from scratch but the internet made it sound like a science experiment, take a breath. At its heart, a starter is nothing more than flour and water left to attract the wild yeast and friendly bacteria that are already floating around your kitchen.
Feed that mixture a little every day and within about a week you’ll have a bubbly, tangy culture strong enough to raise a loaf of bread — your very own sourdough bread starter, with no packet of commercial yeast required. This guide walks you through it one day at a time, tells you exactly what “ready” looks like, and points out the tiny mistakes that trip most people up on their first try.
Just 2 ingredients
Flour and water. That’s the entire shopping list for the starter itself.
About 7 days
Most starters wake up and get bake-ready in 7 to 14 days, depending on your kitchen’s warmth.
One clean jar
A wide-mouth mason jar and a spoon are all the equipment you truly need.
Low waste option
Prefer not to toss discard? We include a small-batch, low-discard rhythm below.
Pin the step-by-step
Tap the pin to save this sourdough starter guide to your baking board — the full 7-day method, right on your phone.
What you need to make a sourdough starter
You almost certainly have most of this already. The only two things worth getting right are a jar you can see through and a way to measure by weight — everything else is flexible.
- A wide-mouth glass jar (about 1 litre / 32 oz)Clear glass lets you watch the bubbles and see how much the starter has risen. A wide mouth makes daily stirring and scooping easy. Don’t seal it airtight — rest the lid on top or use a cloth and band.
- Unbleached flourAll-purpose works, but many bakers start with whole wheat or rye for the first couple of days because they ferment faster, then switch to all-purpose or bread flour.
- Filtered or de-chlorinated waterChlorine in tap water can slow the wild yeast. If your tap is heavily chlorinated, use filtered water or leave tap water out overnight before using.
- A digital kitchen scaleThe single biggest upgrade to your success rate. Sourdough is about ratios by weight, and a scale takes all the guesswork out. Cups of flour vary wildly; grams don’t.
- A spatula or spoon & a rubber bandFor mixing, and for marking the starter’s level on the jar so you can see it rise.
If you’d rather not hunt for pieces, a ready-made kit bundles the jar, scale, and tools together. See our picks in the best sourdough starter kits — handy if you’re gifting or just want to start today without a shopping trip.
Sourdough starter recipe (from scratch)
Here’s the core rhythm. You’ll mix once to begin, then repeat one simple feeding each day. Weights are given because they’re reliable — but I’ve added rough cup equivalents in case you’re mixing your very first batch before your scale arrives.
7-Day Sourdough Starter
A simple flour-and-water culture you can build on any kitchen counter.
Ingredients (per feeding)
- 50 g unbleached flour (about ⅓ cup) — whole wheat or rye for Days 1–2, then all-purpose or bread flour
- 50 g filtered water (about 3½ tbsp), room temperature
Method
- Day 1 — Mix. In your clean jar, stir together 50 g flour and 50 g water until no dry streaks remain. It’ll look like thick paste. Scrape down the sides, mark the level with a rubber band, and rest the lid on top. Leave it somewhere warm (around 21–26°C / 70–78°F).
- Day 2 — Watch. You may see a few bubbles or nothing at all — both are normal. Give it a stir. No feeding needed yet; you’re just letting the wild yeast wake up.
- Days 3–4 — Start feeding. Discard about half the starter, then feed with 50 g fresh flour and 50 g water. Stir, re-mark the level. You should start seeing more bubbles and a pleasant tangy or slightly sour smell.
- Days 5–6 — Feed daily. Keep discarding half and feeding once a day. The starter should begin rising and falling predictably between feedings and smell mildly sour, like yogurt or beer.
- Day 7 — Test for readiness. Your starter is ready when it reliably doubles in size within 4–8 hours of feeding and is full of bubbles. To confirm, drop a spoonful in water — if it floats, it’s ready to bake with.
- Keep it alive. Once active, feed daily if you keep it on the counter, or move it to the fridge and feed once a week (see Store & Revive below).
Many starters go quiet around Days 3–4 after an early burst of bubbles. This is normal — the first bubbles are often the wrong bacteria settling out. Keep feeding on schedule and the real yeast usually takes over within a day or two.
What to bake once it’s alive
The moment your starter passes the float test, these are the loaves to reach for first — all built around this exact starter:
The 7-day sourdough starter schedule
If you only save one thing from this page, make it this table. It shows exactly what to do each day and — just as important — what your starter should look and smell like so you know it’s on track.
| Day | What to do | What you’ll see |
|---|---|---|
| Day 1 | Mix 50 g flour + 50 g water. Rest, lid ajar. | Thick paste, no activity. Totally normal. |
| Day 2 | Just stir. No feeding. | A few bubbles, or none. Faint smell. |
| Day 3 | Discard half, feed 50 g + 50 g. | More bubbles, tangy or funky smell. |
| Day 4 | Discard half, feed once. | Often a lull — activity may dip. Keep going. |
| Day 5 | Discard half, feed once. | Rising visibly, sour-yogurt smell. |
| Day 6 | Discard half, feed once. | Predictable rise & fall, lots of bubbles. |
| Day 7 | Feed, then do the float test. | Doubles in 4–8 hrs, floats in water = ready! |
Seven days is the average, not a rule. A warm kitchen can produce a bake-ready starter in 5 days; a cool one can take 10–14. Trust the signs — doubling reliably and passing the float test — over the calendar.
Tips for making a sourdough starter that actually works
These are the small habits that separate a sluggish, sad jar from a starter that’s doubling like clockwork by the end of the week.
Variations & low-waste options
Once you understand the basic flour-plus-water rhythm, you can adjust the starter to fit your flour, your schedule, and how much discard you’re willing to deal with.
Whole wheat or rye starter
Feed with whole wheat or rye instead of all-purpose for a starter that’s faster, more active, and deeper in flavor. Many bakers keep a rye starter specifically for hearty loaves — it pairs beautifully with our sourdough rye bread.
Low-discard / small-batch starter
Hate throwing flour away? Build a smaller starter. Instead of 50 g feedings, keep just 20 g of starter and feed it 20 g flour + 20 g water. You’ll waste far less while it establishes, then scale up only when you’re ready to bake.
A gentler, less-sour starter
Prefer a milder, lower-tang loaf? Feed more often (twice a day) and use your starter at its peak, right after it’s doubled. A younger starter tastes mellow and slightly sweet rather than sharply sour — a nice option if you’re baking for a crowd that isn’t sold on tang yet.
The half you’d normally toss is perfect for pancakes, crackers, or a quick sourdough focaccia. Our sourdough focaccia recipe is the easiest way to use up discard while your main starter keeps growing.
Storing, caring for & reviving your starter
Caring for a sourdough starter is easier than making one. A healthy starter can last indefinitely — bakers pass them down for decades. How you store it just depends on how often you bake.
Baking often (a few times a week)
Keep it on the counter and feed it once a day. It stays lively and ready to use whenever you are.
Baking occasionally
Move it to the fridge. Feed it once, let it sit out for an hour, then refrigerate — it now only needs feeding about once a week. The cold slows the yeast right down.
Waking a sleepy fridge starter
Pull it out, discard down to a couple of spoonfuls, and feed 50 g flour + 50 g water. Leave it at room temperature. Within a feeding or two — usually a day — it’ll be bubbling and bake-ready again. A dark liquid on top (called “hooch”) just means it’s hungry; stir it in or pour it off and feed.
A well-fed starter survives 2–3 weeks in the fridge untouched. For longer breaks, spread a thin layer on parchment, let it dry completely, and store the flakes in an airtight jar — they rehydrate months later.
Sourdough starter troubleshooting
Almost every “help, my starter is broken” moment is normal and fixable. Here are the ones people worry about most.
Sourdough starter FAQ
How long does it take to make a sourdough starter?
Most sourdough starters are bake-ready in about 7 days, though it can take anywhere from 5 to 14 days depending on your kitchen’s temperature and the flour you use. Warmer kitchens are faster. Rather than counting days, watch for the starter reliably doubling within 4–8 hours of feeding and passing the float test.
Do I need a mason jar to make a sourdough starter?
Not specifically, but a wide-mouth glass jar (like a 32-oz mason jar) is ideal. Clear glass lets you watch the bubbles and the rise, and a wide mouth makes stirring and scooping easy. Any clean glass container of similar size works — just don’t seal it airtight.
What flour is best for starting a sourdough starter?
Whole wheat or rye flour is best for the first day or two because they ferment quickly and are packed with wild yeast. After that, you can switch to all-purpose or bread flour for regular feedings. Use unbleached flour when you can, since bleaching can inhibit fermentation.
Why does my starter smell sour or like alcohol?
A pleasant sour, tangy, or yeasty smell is exactly what you want. A sharp nail-polish or alcohol smell just means your starter is hungry — feed it, and consider feeding a little more often or with a bit more flour. Only pink or orange streaks and fuzzy mold are cause to throw it out.
How do I know when my sourdough starter is ready to bake with?
Your starter is ready when it reliably doubles in size within 4–8 hours of feeding and is full of bubbles. Confirm with the float test: drop a small spoonful into a glass of water — if it floats, it’s active enough to raise bread.
Do I have to discard part of my starter?
Discarding keeps the starter from growing huge and keeps the flour-to-starter ratio healthy. If you’d rather not waste flour, keep a smaller starter (feed just 20 g at a time) or use the discard in pancakes, crackers, or focaccia instead of throwing it away.
Can I make a sourdough starter without commercial yeast?
Yes — that’s the whole point. A sourdough starter captures the wild yeast and bacteria naturally present in flour and in the air of your kitchen. You never add packaged yeast; flour and water are all you need.
Start your jar today
Making a sourdough starter from scratch takes five minutes a day and a little patience — and at the end of the week you’ll have a living culture that can bake bread for years. Mix your first jar tonight, and by next weekend you’ll be pulling a real loaf from the oven.
📌 Save this guide to Pinterest so the day-by-day schedule is with you all week — then come back and tell us how your first bake turned out.
See the starter kits we recommend →
