It smells like nail polish.

Too much acetic acid, often from long gaps or a cold room. Feed more often with white flour for a few days.

Can I use all-purpose only?

Yes, it just takes longer. A couple of rye or whole-wheat feeds at the start still help.

How to make my own

Sourdough Starter

Flour, water, a jar, and about a week of twice-daily feeds until it doubles on schedule.

howtomakemyown4.8(3.9k reviews)20 min total

Jump to Recipe

Project At-A-Glance

Difficulty: medium
Active Time: 11 min
Total Time: 20 min
Yield: 1 active starter jar

Materials & Tools

0/6

A clear 500 ml jar with a loose lid or cloth
Whole wheat or rye flour for the first two days (more microbes)
Plain white bread flour after that
Room-temperature water, not chlorinated if you can help it (leave tap water out overnight)
A rubber band to mark the height after each feed
A kitchen scale (grams beat cups here)

Starter is a wet flour culture you keep alive, not a packet of instant yeast. You are selecting wild yeast and bacteria that already live on grain and in your kitchen.

The only job for day one through seven is: mix, wait, discard, feed. Do not bake with it until it doubles in 4 to 8 hours after a feed and smells tangy, not like paint or vomit.

Step-by-step

Step 1: Day 1, morning: mix 50 g whole-grain flour and 50 g w…

Day 1, morning: mix 50 g whole-grain flour and 50 g water in the jar. Scrape the walls. Cover loosely. Leave at 22–26 °C if you can.

Step 2: Day 2, morning: it may look sleepy

Day 2, morning: it may look sleepy. Stir, then add 50 g flour and 50 g water. Mark the height with the band.

Step 3: Day 3 onward, morning and night: discard down to 50 g…

Day 3 onward, morning and night: discard down to 50 g of the mixture. Feed 50 g white flour and 50 g water. Stir until no dry pockets remain.

Step 4: If it hoists the band in 6 hours and is full of bubbl…

If it hoists the band in 6 hours and is full of bubbles, you are close. If it never rises, the room is cold — move it to the oven with the light on, door cracked.

Step 5: When it doubles predictably twice in a row, it is rea…

When it doubles predictably twice in a row, it is ready for a loaf. Use it at peak, not after it has collapsed.

Step 6: For the fridge: feed, let it rise 1 hour, then cold-s…

For the fridge: feed, let it rise 1 hour, then cold-store. Feed at least once a week. Bring it out and give two room-temperature feeds before baking.

Email me the checklist

Checklist email is coming soon — use Print / save PDF for now, or check the materials list above.

Notes

Pink, orange, or fuzzy growth is mold. Throw the jar contents out and start over. A dark hooch on top is hunger — pour it off and feed.
Discard is still flour paste. Cook it as pancakes; do not pour pounds of it down a slow drain.
Whole-grain at the start jump-starts activity. Switching to white later makes a milder, more predictable rise.

FAQ

Otherwise the jar becomes a sour ocean you cannot keep acidic enough. The remaining 50 g is plenty of culture.

Safety note: this is practical DIY guidance, not medical, chemical, or professional advice. Skip anything that feels unsafe for your setup.

kitchen Bread Fermentation Baking