How to Make Your Own Sourdough Starter.

You will need:

2 clean pint glasses (so you can swap between them each day)
Wholegrain rye flour
Strong white flour (added later)
Room-temperature water (around 25–30°C — warm, not hot)
Clingfilm or a loose cover

If your kitchen is cool, you can pop the glass somewhere warm and steady, like an airing cupboard, on top of the fridge, or near a radiator — just avoid direct heat.

Day 1 – The Beginning

Mix 50g rye flour with 50ml water in a pint glass until smooth, like a thick paste.
Cover loosely with clingfilm.
Leave it at room temperature (ideally 20–24°C) for 24 hours.
This is when the wild yeast and natural bacteria start to wake up and multiply.

Day 2 – The First Feed

After 24 hours, you may notice a few tiny bubbles or a slightly tangy smell — that’s a good sign.
Peel away any dry crust that’s formed on top.
Scoop out 50g of the starter (the middle part under the crust) and transfer it into your second pint glass.
Add 50g rye flour + 50ml water and mix well.
Cover again with clingfilm and leave at room temperature for another 24 hours.

(From now on, you’ll always move the starter into a clean pint glass each time you feed — it keeps things fresh and lets you see how much it rises.)

Day 3 – Keep Feeding

Repeat the same process:
- Take 50g of the starter, put it in the clean pint glass,
- Add 50g rye flour + 50ml water,
- Mix and cover loosely.
Keep it somewhere warm — an airing cupboard is perfect if your house is on the cool side.
By now you should start to see more bubbles forming and the starter might even rise a little.

Day 4 – The Double Feed Day

Give your starter two feeds today — one in the morning (around 9am) and one in the evening (around 9pm).
Each time, do exactly the same:
- Move 50g starter into the other pint glass,
- Add 50g rye flour + 50ml water,
- Mix, cover, and leave to rest in a warm spot.

This extra feed strengthens the yeast and bacteria, building up their activity so the starter becomes more reliable and consistent.

Day 5 – The Transition

Morning feed (9am):
- Take 50g starter and mix it with 25g rye flour, 25g strong white flour, and 50ml water.
- Stir until smooth and cover with clingfilm again.

Adding strong white flour now starts to replicate the flour you’ll actually be baking with. It trains the microbes in your starter to thrive on the same type of flour that will be in your bread dough.

Evening feed (9pm):
- Do exactly the same again:
  50g starter + 25g rye + 25g strong white + 50ml water.

When it rises this time, you might notice the bubbles are smaller — that’s perfectly normal. The strong white flour gives the starter a silkier texture, so the rise looks smoother and more even rather than frothy.

If it’s doubled in size within 12 hours, feed it again as above.
If it hasn’t quite doubled, leave it 24 hours before the next feed — but it almost certainly will.

Day 6 – Strength Building

Feed it again morning and evening, exactly as before:
50g starter + 25g rye + 25g strong white + 50ml water.

By this stage, your starter should be doubling between feeds — rising up the sides of the pint glass, full of tiny bubbles, and smelling cleanly sour (like yoghurt or fruity beer).

Day 7 – The Big Reveal

Give it one final feed in the morning (same quantities).
Leave it in a warm spot for 6–12 hours.

If it’s doubled again, congratulations — you now have your very own strong, active sourdough starter ready to make the freshest and best sourdough bread in the world.

It should:

Rise and fall predictably,
Smell pleasantly tangy,
Be full of tiny bubbles,
And leave streaks on the glass where it’s risen.

Tips for Success

Keep your clingfilm loose — you want to trap moisture, not pressure.
If it forms a crust, just peel it off before feeding.
Warmth speeds fermentation, cold slows it — the airing cupboard trick is your friend.
Always move your starter into the clean pint glass for each feed.

​How to Make Your Own Sourdough Starter.