Sourdough FAQ

Sourdough starter is a natural culture of wild yeast and lactic acid bacteria that ferments flour and water. It’s used as a leavening agent (instead of commercial yeast) and adds flavour and strength to dough.

Feeding means discarding a portion of starter, then adding fresh flour and water. This refreshes the culture, gives it new food, and keeps it strong and balanced.

As the microbes consume sugars, they produce gas (CO₂) which inflates the starter. Once food runs low (or it becomes too acidic), it will peak and then collapse.

Doubling is helpful but not the only sign. Rise depends heavily on jar shape, flour type, hydration, and temperature. Look for consistent bubbling, a predictable peak time, and a pleasant sour aroma.

Dried starter is dormant and shelf-stable. It needs rehydration and several feeds to become strong. Active (wet) starter is already alive and usually gets baking-ready faster.

Commonly 3–7 days to see good activity, and sometimes 7–14 days to become fully strong and predictable (especially in cooler kitchens).

Early on, you’re mostly rehydrating and rebuilding population. Activity often ramps up after a few consistent feeds once the culture rebalances.

Use a small jar, keep it warmish and consistent, feed at the same time each day, and keep your starter at a workable thickness (not too runny). Small, regular feeds build strength quickly.

For feeding/bench activity, use a loose lid (or a lid resting on top) so gas can escape. For fridge storage, a tight lid is fine.

Not required, but it’s fine. Stirring can redistribute food and microbes and is helpful if you see liquid separating on top.

At room temperature, most starters do well with daily feeding. In warmer weather or if the starter peaks quickly, you may need 2 feeds per day (or a larger feed ratio).

A common starting ratio is 1:1:1 (starter:water:flour by weight). If your starter is peaking too fast, use a bigger feed like 1:2:2 or 1:3:3.

Yes (or use it in discard recipes). Without discarding, the jar grows endlessly and the starter can become overly acidic and sluggish.

Thicker starter traps gas better and often rises more. A good target is a very thick batter (like a stiff pancake batter), not a runny pourable mix.

Most starters love a mix of white bread flour and a little wholemeal/rye for extra nutrients. Rye often boosts activity.

Yes. Expect a short adjustment period (rise, smell, and timing can change). If you want the smoothest transition, change gradually over a few feeds.

Chlorine/chloramine can slow fermentation. Filtered, dechlorinated, or rested water is best. If your tap water is heavily treated, try filtered water.

Most starters are happiest around 21–27°C. Warmer = faster; cooler = slower. Consistency matters more than chasing the “perfect” number.

Use cooler water, feed at a higher ratio (e.g. 1:3:3), keep it in the coolest part of the house, or use the fridge to slow things down.

Give it more time between feeds, use slightly warmer water, and keep it somewhere stable (inside a cupboard, or near — not on — a gentle warmth source).

When it rises reliably after feeding, smells pleasant (tangy/yeasty), and hits a predictable peak. A strong starter should be able to raise dough consistently, not just bubble.

Not necessarily. The float test can be unreliable depending on hydration and flour. Consistent rise + timing + aroma are usually better indicators.

Typically at (or just before) peak activity — often 4–6 hours after feeding depending on temperature and feed ratio.

Usually yes. Feed, wait until it’s active/near peak, then build your dough. This gives you the most reliable fermentation and rise.

You can, but it’s less predictable. If your starter has been refrigerated, one room-temp feed before baking usually improves strength and timing.

Common causes: starter not fully mature, dough too cool, too much salt, or using starter past peak. Warmer proofing and using starter at peak helps.

Most home bakers only need a small “mother” starter (e.g. 20–50 g) and build up what they need for baking. Smaller starters are easier and waste less flour.

Discard can be used in pancakes, waffles, crackers, muffins, pizza bases, and more. If you don’t want to use it, you can compost it.

Yes. Use a larger feed ratio and give it time to peak. Build what you need in one or two steps rather than keeping a huge starter permanently.

Feed it, let it start fermenting for a short time at room temperature, then refrigerate with a tight lid. Many people refresh weekly (or before the next bake).

Often 1–2 weeks is fine. Longer is possible, but it may become more acidic and need a couple of feeds to bounce back.

Hooch is alcohol-like liquid produced when the starter runs out of food. It’s usually harmless. Pour it off (or stir in), then feed the starter.

Often it’s either too runny to trap gas, too warm/cold, or not strong yet. Make it thicker, keep temperature steady, and stick to consistent feeds for several days.

That usually means it’s peaking fast (warm conditions or small feed). Use a bigger feed ratio (1:2:2 or 1:3:3) or keep it slightly cooler.

That’s commonly from hunger/imbalance. Increase feed ratio, feed more regularly, and keep conditions steady. It often normalises within a few feeds.

Usually from airflow/drying. Use a better-fitting lid (still loose for bench), or stir down the sides and keep the jar out of direct drafts/sun.

Mould is fuzzy and often coloured (green/blue/black/pink) and may smell off. Dried flour is usually powdery and wipes away easily. If you’re unsure, it’s safest to discard and restart.

Some discoloration and liquid separation can happen with hunger. But if you see strong colours or fuzzy growth, discard.

No. Clean is enough. Avoid antibacterial residues and strong fragrances.

Keep a small starter, feed consistently, use good flour, and keep temperature steady. Consistency beats perfection.

Yes. A simple backup is to dry a small amount of starter or keep a “spare” jar in the fridge. Backups remove all stress if something goes wrong.

Weekly is a great habit, but if you bake less often, refresh before baking and again after. If it smells very acidic or has lots of hooch, give it 1–2 room-temp feeds.