How to Make Sourdough Starter: Feed, Wait, and Know It Is Ready

A sourdough starter is a living culture of wild yeast and lactic acid bacteria fed on flour and water. You do not need a packet of yeast from the store — just consistency, a jar, and about 5–10 days before the culture is strong enough to leaven bread. The process is mostly waiting and feeding, not advanced technique.

What You Need

Ingredients

• Whole wheat or rye flour (best for kick-starting microbes; you can switch later)
• All-purpose or bread flour (for maintenance feeds)
• Water — filtered or dechlorinated if your tap water is heavily chlorinated

Equipment

• Glass jar ( pint / 500 ml or larger)
• Loose lid, cloth cover, or jar lid left slightly open
• Spoon or spatula
• Kitchen scale (recommended) or measuring cups
• Rubber band to mark starter level (optional but helpful)

Day 1: Mix the Base

Combine in your jar:

• 50 g whole wheat or rye flour (1/3 cup approx.)
• 50 g water (1/4 cup approx.)

Stir to a thick paste. Scrape sides clean. Cover loosely. Keep at 70–78°F (21–26°C) — a warm kitchen counter works; cold slows everything.

Mark the level with a rubber band.

Days 2–3: First Feeds

You may see no activity or small bubbles — both normal. Some starters smell fruity or stinky early; that often mellows.

Feed once every 24 hours:

1. Discard half the starter (about 50 g — compost or trash; do not pour thick dough down the drain)

2. Add 50 g flour and 50 g water

3. Stir, mark level, cover

Using a scale keeps hydration consistent (100% hydration = equal weights flour and water).

Days 4–7: Increase Feeding

When bubbles appear and volume rises between feeds, move to twice-daily feeds if your kitchen is warm, or continue daily if cool.

Each feed:

1. Discard all but 25–50 g starter (keep a tablespoon-sized core)

2. Add 50 g flour + 50 g water (or 100 g each if you are building volume for baking)

Watch for predictable rise: starter should double within 4–8 hours after feeding at peak activity.

How to Know It Is Ready (Pass the Float Test)

At peak rise (domed top, lots of bubbles):

1. Drop a small spoonful of starter into a glass of water.

2. If it floats, it is likely strong enough to bake.

3. If it sinks, keep feeding 2–5 more days.

Also note pleasant tangy smell — not nail polish remover every day ( occasional sharp notes can happen mid-feed cycle).

Switching Flours

After the culture is stable, you can feed with bread flour or all-purpose for milder flavor. Whole grains ferment faster and add complexity.

Maintaining Your Starter

Daily (counter)

Feed every 12–24 hours if kept at room temperature — impractical for most people long term.

Weekly (fridge)

After a feed, refrigerate once doubled. Feed once a week: discard, refresh, let sit 1–2 hours at room temp, return to fridge.

Before baking

Pull starter out, feed 1–2 times at room temp to wake it up. Plan 4–12 hours lead time depending on strength.

What to Bake First

Once your starter passes the float test, try sourdough discard pancakes or crackers before a full loaf — less waste while you learn timing. For bread, many beginners start with a simple boule using roughly 200–250 g active starter, depending on the recipe.

Common Questions

Do I have to discard every feed? In home kitchens, yes — otherwise volume explodes and the culture skews acidic. Use discard in discard recipes rather than throwing it away when possible.

Can I use only all-purpose flour? Yes, after the culture is established. Whole grains help kick-start early fermentation.

My kitchen is cold — now what? Below 65°F (18°C), fermentation slows. Try a warmer microclimate (oven light, proofing box) or extend timelines without panic.

Troubleshooting

| Problem | Likely cause | Fix |

| --- | --- | --- |

| No bubbles after 5 days | Too cold, chlorinated water, or infrequent feeds | Warm spot; filtered water; feed twice daily |

| Gray liquid on top ("hooch") | Hungry starter | Pour off or stir in; feed immediately |

| Mold (fuzzy colors) | Contamination | Discard; sanitize jar; restart |

| Smells like acetone | Underfed at peak | Feed more often; discard larger portion before feed |

| Never passes float test | Weak culture or tested at wrong time | Feed 3+ days; test at maximum rise |

| Starter rises then collapses | Normal cycle | Feed at peak or just after collapse |

Food safety

Fermentation is generally safe with clean jars, regular feeds, and no mold. If you see pink, orange, or fuzzy growth, discard the starter. Wash hands before feeding. Do not consume raw starter in large amounts if you are immunocompromised without consulting a professional.

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*Sourdough involves living cultures and flour fermentation. This guide is for home baking education, not medical or dietary advice.*