Your Sourdough Starter

How to get one, keep it alive, and use it

What Is a Sourdough Starter?

A sourdough starter is a live culture of wild yeast and beneficial bacteria, kept alive in a simple mixture of flour and water. It's what makes sourdough bread rise and gives it that distinctive tangy flavour - no commercial yeast required.

Unlike a jar of dried yeast you keep in the back of a cupboard, a starter is a living thing. It needs feeding, a little attention, and a stable home. In return, it will reliably leaven your dough for years - even decades. The good news: once you understand the rhythm, it takes almost no effort to maintain.

How to Get Your Starter

There are three ways to get your hands on a sourdough starter. Any of them works - choose whichever suits you.

Option 1 - Get a Piece From a Friend

This is the fastest and most reliable way. If someone you know already bakes sourdough, ask them for a spoonful of their starter (around 20-30 g is plenty). Mature starters are robust, active, and predictable. You skip the two-week building process entirely and can be making dough within days.

Tip: Any healthy starter works regardless of what it was originally used for. Flour type and hydration can always be adjusted once it's in your hands.

Option 2 - Buy a Starter

Dried and live sourdough starters are widely available online and in some specialty food shops. Dried starters have an impressive shelf life and rehydrate easily - follow the seller's instructions, and within a few days of feeding you'll have an active culture ready to use.

This is a great option if you want a starter with a known history (there are sellers offering cultures that are decades or even a century old, which is admittedly a little exciting).

Option 3 - Build One From Scratch

Making your own starter from scratch takes about 7-14 days. It requires no special equipment - just flour, water, a jar, and patience. The wild yeast and bacteria come naturally from the flour and the air around you, which means every homemade starter ends up being slightly unique to where you live.

What You'll Need

• Unbleached flour (whole wheat or rye flour works best for the first few days as it contains more wild yeast; you can switch to all-purpose later)
• Non-chlorinated water (filtered or left to sit out overnight if you're on tap water)
• A clean glass jar (at least 500 ml capacity)
• A kitchen scale
• A rubber band or piece of tape to mark the level

Days 1-2: The First Mix

1. Combine 50 g flour and 50 g water in your jar. Stir vigorously until no dry flour remains.
2. Cover loosely (a cloth or lid resting on top - not sealed, it needs to breathe).
3. Leave at room temperature (ideally 21-24°C / 70-75°F). Mark the level with your rubber band.

Don't panic if nothing happens in the first 24 hours. It's normal.

Days 3-7: Daily Feeding

1. Once a day, discard all but 20-30 g of your starter.
2. Add 50 g flour and 50 g water. Stir well, cover, mark the level, and leave at room temperature.
3. Watch for bubbles and a rise in level - this is fermentation starting.

Why discard? You're not throwing away hard work - you're keeping the population in check. A small, well-fed starter is far more active than a large, underfed one.

Days 7-14: Signs It's Ready

Your starter is ready to use when it consistently:

• Doubles in size within 4-8 hours of a feeding
• Looks bubbly and airy throughout
• Smells pleasantly tangy or slightly yeasty (not like nail varnish or acetone, which means it needs more frequent feeding)
• Passes the float test: drop a small spoonful into water - if it floats, it's active enough to leaven dough

Note: Some starters take up to 14 days. Cooler kitchens slow things down. If yours seems sluggish, try a warmer spot or use lukewarm water for feedings.

How to Keep Your Starter Alive

Once your starter is active, maintaining it is straightforward. The method below is designed for home bakers who don't bake every single day - it uses the fridge as a pause button and keeps effort to a minimum.

Step 1 - Use It

When you're ready to bake, take your starter straight from the fridge. Use however much your recipe calls for. Don't wait for it to come to room temperature first - it goes straight into the dough mix.

Step 2 - Feed the Leftovers

After taking out what you need, you'll have some starter left in the jar - typically 20-40 g. That's your reserve. Feed it immediately:

1. Add 50 g flour to the jar
2. Add 50 g water
3. Stir well until fully combined

Step 3 - Let It Rise

Leave the jar out at room temperature for a few hours after feeding. You want to see it become bubbly and active before you put it away - this confirms the culture is healthy and has enough fuel to stay dormant in the fridge.

Timing tip: A few hours at room temperature is usually enough. You don't need to wait until it has fully peaked - just until it's clearly alive and moving.

Step 4 - Back in the Fridge

Once it's visibly active, place it on the top shelf of the fridge. The cold slows fermentation dramatically, essentially putting your starter to sleep. It will be happy there until next time.

Storage Tips

• Top shelf of the fridge is ideal - it's the most stable temperature zone, away from the door (which fluctuates) and the freezer section (too cold).
• Use a jar with a lid that sits loosely or has a small gap. The starter still produces small amounts of gas even in the fridge, so you want it to be able to breathe slightly.
• Label your jar with the date of the last feeding so you always know where you are.
• A healthy starter can survive in the fridge for over a month without feeding. That said, if you have a young starter (under a few months old), feeding it at least every couple of weeks is recommended to keep the culture strong and active.
• If you don't bake for more than a week, give it a quick feed before putting it back - just to top it up.

Troubleshooting

Dark liquid on top ("hooch"): A dark, watery layer sometimes appears on top after the starter has been sitting for a while. This is just alcohol - a sign the starter has run out of food. Pour it off, give the starter a good feed, and it will recover quickly.

It smells very sour or like alcohol: This is hunger. The starter has eaten through its food supply and the acid is building up. Feed it, let it rise at room temperature, and it should perk up within a few hours.

No activity after feeding: Check the temperature - cold kitchens slow everything down significantly. Try placing the jar somewhere warmer (on top of a fridge, near an oven, in an oven with just the light on). If there's still no activity after 24 hours, feed again and give it more time.

Pink, orange, or fuzzy growth: This is mould. Discard immediately and start fresh. Mould is rare if you keep your jar clean, but it can happen. Always feed into a clean jar if in doubt.

The Short Version

Keep your starter in the fridge. Take it out when you want to bake, use what you need, feed the leftovers (50 g flour + 50 g water), leave it out for a few hours to get active, then put it back. That's it. A healthy starter managed this way can last indefinitely with very little effort.

Ready to make dough? Head to the companion guide: The Sourdough Dough Guide - Pizza, Burger Buns & Pita Breads.