Can I use a mason jar for sourdough starter?

Yes. Wide-mouth mason jars are ideal. Keep the lid loose or use a breathable cover so gas can escape.

How warm should my kitchen be for starter?

Aim for 70–75°F (21–24°C). Warmer speeds activity; cooler slows it down.

How do I know when the starter is ready?

It doubles in 4–6 hours after feeding, looks bubbly/airy, and smells pleasantly tangy. A float test can help but isn’t definitive.

What if I see gray liquid (hooch)?

That’s a sign of hunger. Stir it in or pour off and feed. Resume regular feedings.

When should I throw a starter away?

If you see mold or pink/orange streaks, discard and start again.

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Learn how to make a sourdough starter from scratch in just 7 days—bubbly and ready to bake. Step-by-step photos and tips included.

How to Make and Maintain a Sourdough Starter (Beginner’s Day-by-Day Guide)

Sourdough isn’t just bread—it’s a living, breathing kitchen companion. In just one week, you can create your starter from scratch using nothing more than flour, water, and a little patience.

I’ll guide you step-by-step, from that first mix to a bubbly, happy starter ready to bake the bread of your dreams. Along the way, you’ll learn how to keep it thriving for years, troubleshoot the tricky days, and even make delicious recipes from your starter’s discard. By the end, you won’t just have a jar of fermenting magic… you’ll have a new member of your kitchen family.

If you have kids or grandkids, starters make the perfect science experiment! They will see the effects of mixing flour and water and all the stages it goes through in order to create yeast. They can see it and smell it right as it is happening.

I started this journey in the summer of 2018. We visited San Francisco and fell in love with their sourdough bread and the local bakeries. My husband and I bought a few books and learned the process.

Our starter is now 7 years old, gets fed regularly, and makes the most delicious breads. Her name is Betty.

I recommend you find a name for yours—here are some vintage ideas: Rita, Doris, Audrey, Irene, Ruth, Ethel. To create this post, I started a new one, as you will see below. Her name is Mildred. Now I have a Betty and a Mildred.

What is a Sourdough Starter?

A sourdough starter is a natural leavening made by fermenting flour and water. Wild yeast and lactic acid bacteria develop in the mixture, creating the lift and tangy flavor that make sourdough special—no commercial yeast needed.

Active sourdough starter in a jar with visible bubbles — An active starter looks airy and bubbly and rises predictably after feedings.

Benefits of Sourdough Bread

Easier to digest: Long fermentation partially breaks down gluten and starches (not gluten-free).
Lower glycemic impact: Organic acids can slow carbohydrate absorption.
Better mineral absorption: Fermentation reduces phytic acid, improving availability of iron, magnesium, and zinc.
Beneficial compounds: Fermentation produces bioactive peptides and antioxidants.
Naturally longer shelf life: Organic acids help inhibit mold.
Great flavor & texture: Tangy, complex taste with a chewy, moist crumb.
May be more tolerable for some: Long-fermented sourdough can be easier for some with mild sensitivities (not suitable for celiac). My mom, for example, can’t usually tolerate regular bread—only homemade sourdough.

Ingredients

Unbleached all-purpose or bread flour (whole wheat or rye can boost early activity)
Room-temperature water (filtered/dechlorinated if possible)

Equipment

Sourdough starter tools on counter: jar, scale, spatula

Glass mason jar (start with 16 oz; move to 32 oz as activity grows)
Kitchen scale (best accuracy)
Spoon or spatula
Rubber band or tape to mark the rise level

Jar on digital scale showing empty jar weight

Pro tip: Weigh your empty jar and write that number down. When it’s time to discard half, subtract the jar’s weight from the total to know exactly how much starter to remove—no guesswork. Mine is 763 grams.

Can I use a mason jar? Yes! Wide-mouth mason jars are ideal: clear, sturdy, and easy to clean. Just don’t seal it airtight. You can also use these plastic containers from Amazon.

Day-by-Day Sourdough Starter Instructions

Use equal weights of flour and water for feedings (a 1:1:1 ratio of starter:water:flour by weight during the build). Keep the jar at 70–75°F (21–24°C). Mark the level with a rubber band after each feeding.

Day 1: freshly mixed flour and water in a jar — **Day 1 — Mix & Rest:** Freshly mixed starter—no bubbles yet (normal).

Day 1 — Mix & Rest

In the jar, mix 60 g flour + 60 g water until no dry bits remain.
Scrape sides clean, cover loosely, and rest 24 hours at room temperature.

Day 2 starter with a few bubbles near surface — **Day 2 — Tiny Signs of Life:** A few bubbles and a mild sweet/earthy smell. The wild yeast is waking up.

Day 2 — First Feeding

Discard half of the mixture (save for discard recipes if you like). This is where weighing your empty jar helps: mine weighed 763 g. After Day 1, total was 883 g. Since I need to discard 60 g, my new weight (before feeding) should be 823 g (883–60).
Add 60 g flour and 60 g water. Stir well, cover, and rest 24 hours.

Day 3 starter with noticeable rise and bubbles — **Day 3 — First Big Rise:** More bubbles, lighter texture, and a faint tangy aroma (funky is okay).

Day 3 — First Big Rise

Many starters show a big rise today; it’s okay if yours takes longer.
Repeat: discard half, then feed 60 g flour + 60 g water.
If it rises and falls before 24 hours, switch to feedings every 12 hours.

Day 4 quiet phase with fewer bubbles and possible hooch — **Day 4 — The Quiet Phase:** Fewer bubbles, little rise, maybe a thin layer of hooch. Normal!

Day 4 — The Quiet Phase (Don’t Panic!)

Today your starter might look less active fewer bubbles, little or no rise, and sometimes a thin layer of liquid (hooch) on top. This is normal. The first wave of microbes is giving way to wild yeast and lactic acid bacteria, building strength.

Pour off hooch for a milder flavor, or
Stir it in for a tangier taste.

Feed immediately and keep it warm. In the next few days, you’ll see it bounce back and rise more consistently.

Day 5 starter full of bubbles and rise — **Day 5 — Active & Hungry:** A thick web of bubbles, pleasant sour smell, noticeable rise after feeding.

Day 5–6 — Activity Returns

Bubbles become more evenly distributed.
Continue discarding and feeding once or twice daily as needed.
The starter should rise reliably after feeding.

Day 7 bubbly, bake-ready starter — **Day 7 — Bubbly & Bake-Ready:** Doubles in 4–6 hours and usually passes the float test.

Day 7 and Beyond — Ready to Bake

Feed once more. When it doubles in 4–6 hours and is very bubbly, it’s ready.
(Optional) Float test: a small spoonful should float in water (helpful but not definitive).
Move to maintenance: store in the fridge and feed weekly, or keep at room temp and feed daily. If refrigerated, still do a weekly feed/discard.

How to Know When Your Starter is Ready

Rises predictably and doubles within 4–6 hours after feeding
Looks airy and webby with lots of bubbles
Smells pleasantly tangy/yeasty (not harsh or rotten)
Holds shape briefly when spooned (not watery/runny)

Next step: Try your first loaf with my Beginner Sourdough Bread and this focaccia recipe.

Scaling Your Starter for Baking

Now that your starter is strong, choose how much to keep and feed depending on how often you bake. For once-a-week baking, keep a small jar with 50–100 g starter and feed just enough for your bake. If you bake frequently, you may prefer a larger “baker’s jar” like my long-time starter, Betty.

The “Betty Method” (Frequent Baking)

Keep 4 oz (113 g) starter in the jar.
Feed with 4 oz (113 g) water + 4 oz (113 g) flour.
Produces ~220 g discard per feed and leaves plenty of active starter for multiple loaves or discard recipes.

Loaves	Discard Amount	Starter to Keep	Water to Add	Flour to Add	Starter Produced
1 loaf	All but 50 g	50 g	50 g	50 g	150 g
2 loaves	All but 100 g	100 g	100 g	100 g	300 g
3 loaves	All but 150 g	150 g	150 g	150 g	450 g

How to use this: Keep the amount in the “Starter to Keep” column, then feed it equal parts water and flour.
That yields the “Starter Produced” total for your bake.

Feeding & Maintenance

At room temp: Feed every 12–24 hours.
In the fridge: Feed, rest 1 hour at room temp, then refrigerate. Feed weekly.
Keep 50–100 g starter; feed with equal weights of flour and water.
To refresh for baking after refrigeration: do 1–2 room-temp feedings until it doubles in 4–6 hours.

What to Do with Sourdough Discard

Don’t toss it!

Troubleshooting

No bubbles after a few days? Keep going; switch to a warmer spot; try a portion with 20–50% whole wheat/rye.
Gray liquid (“hooch”)? It’s hungry. Stir it in or pour off and feed.
Smells harsh/solventy? Give it a couple of timely feedings; keep at moderate temps. When I first started Betty, one day it smelled like rotten cheese + feet—be patient, feed, and it goes away.
Mold or pink/orange streaks? Discard and start over.

If you made this starter, tag me @livingsweetmoments so I can see your bubbly jars and meet their vintage names!

This post may contain affiliate links. If you purchase through these links, I may earn a small commission at no extra cost to you.

Frequently Asked Questions

How long does it take to make a sourdough starter?

On average, 5–7 days. Some starters are active in 4 days, others may need 10 depending on temperature, flour, and water quality.

Can I use whole wheat or rye flour instead of white flour?

Yes! Whole wheat and rye often kickstart fermentation faster. Many bakers start with a mix, then switch to all-purpose for regular feedings.

What if my starter develops liquid (hooch) on top?

That’s a sign it’s hungry. Stir it back in for tangier flavor or pour it off for milder—and feed as usual.

Why is my sourdough starter not bubbling?

Move it to a warmer spot (75–78°F / 24–26°C), feed on time, include some whole wheat/rye, and make sure you’re discarding enough before each feed.

Can I use tap water?

If your tap water is heavily chlorinated, it can slow fermentation. Use filtered water or let tap water sit out overnight.

How do I know when my starter is ready to bake with?

It doubles in 4–6 hours after feeding, looks bubbly throughout, smells pleasantly tangy, and usually passes a float test.

What can I do with the sourdough discard?

Pancakes, waffles, crackers, muffins, brownies, biscuits, or pizza dough—discard adds great flavor even when it can’t leaven by itself.

Can I store my starter in the fridge?

Yes. Once mature, refrigerate and feed weekly. Before baking, bring to room temp and refresh 1–2 times until it doubles in 4–6 hours.

Yum