How to make a sourdough starter from scratch: feeding, signs it's ready and storing it

TUREFF• •0

A sourdough starter is just flour and water that has been colonised by wild yeasts and lactic acid bacteria. They come from the flour, your hands and the air. Feed it regularly and they settle into a stable culture that raises bread without commercial yeast. It takes a week or two of small daily effort. Here is how.

What you need

Flour: wholemeal or rye flour is best for starting, because it carries more of the natural microbes and nutrients. You can switch to strong white flour once it is established.
Water: tap water is usually fine. If yours is heavily chlorinated, leave it out in a jug for a few hours or use filtered water.
A clean glass jar of around 1 litre with a loose lid.
Kitchen scales. Weighing is far more reliable than cups.
A rubber band or pen to mark the level after each feed, so you can see the rise.

Day 1

Mix 50g wholemeal or rye flour with 50g water in the jar until there are no dry bits. It should look like thick paste. Scrape down the sides, cover loosely and leave it at room temperature, ideally somewhere around 20 to 26°C.

Days 2 to 4

You may see bubbles and a sour or odd smell on day 2. Often this is early bacterial activity rather than the yeast you want, and it frequently goes quiet again on day 3 or 4. This is normal; do not give up. Each day:

Discard all but about 50g of the starter (throw it away or compost it).
Add 50g flour and 50g water and stir well.
Mark the level and cover loosely.

Day 5 onwards

Keep feeding the same way, once a day. If it starts rising and bubbling within a few hours of feeding, move to twice a day, about 12 hours apart. You can switch gradually to strong white flour, or a mix, at this stage. The smell should become pleasantly sour and yeasty, a little like yoghurt or beer.

Signs it is ready

A starter is ready to bake with when, for several days in a row, it:

roughly doubles in volume within about 4 to 8 hours of feeding
is full of bubbles throughout, not only on top
has a domed top at its peak, then starts to fall
smells pleasantly sour rather than like nail varnish or cheese

This commonly takes one to two weeks, sometimes longer in a cool kitchen. The float test (dropping a spoonful in water) is often mentioned, but it is unreliable; a predictable rise is the better sign.

Troubleshooting

No activity at all: move it somewhere warmer, use wholemeal or rye flour, and be patient.
A layer of grey or dark liquid on top: this is called hooch, a sign the starter is hungry. Pour it off or stir it in, and feed it, perhaps more often.
Smells strongly of acetone or nail varnish: also hunger. Feed more often or use a larger feed (for example, 1 part starter to 2 parts each of flour and water).
Rises then collapses quickly: it is very active and peaking fast. Use the starter at its peak, or feed it a bigger ratio to slow it down.
Thin and runny: use a little less water or more whole grain flour.
Mould: fuzzy patches, or pink, orange or red streaks, mean contamination. Throw the whole thing away and start again with a clean jar. Do not try to scrape it off.

Storing it

At room temperature, it needs feeding once or twice a day. Best if you bake often.
In the fridge, it slows right down and needs feeding about once a week. Take it out a day or so before baking and give it one or two feeds at room temperature to wake it up.
Going away? Feed it, then store it in the fridge. A neglected starter often recovers after a few feeds. You can also smear a thin layer on baking paper, dry it completely, crumble it and keep it in an airtight jar as a backup.

Using the discard

The starter you remove each day does not have to go to waste. It can go into pancakes, crumpets, crackers and waffles, usually together with baking powder or soda to help them rise. Keep notes on temperature and timing; it helps you understand your own starter. How is yours coming along? Ask questions or share your starter's name and progress in the comments.