Why Cold Weather Slows Your Starter

A sourdough starter is a living community of wild yeast and lactic acid bacteria. In summer, a warm kitchen can feel like a holiday for them. In a British winter, especially in older houses with draughty windows and north-facing kitchens, temperatures can drop to 14°C or lower overnight. At that point, yeast activity slows dramatically. You might see a few bubbles on the surface but no real rise, and the smell may turn sharp rather than pleasantly yeasty. That does not mean your starter is dead. It is simply cold and sluggish, waiting for better conditions.

The key is to work with the season rather than against it. You do not need a laboratory or expensive equipment, but you do need a thermometer, a little patience, and a feeding routine that matches your kitchen temperature. The following methods are used by home bakers across the UK to keep starters reliable from October through to March.

Find a Reliable Warm Spot — and Measure It

Before you change flour or ratios, check the actual temperature where your starter lives. A digital probe thermometer is one of the best small investments a baker can make. Aim for a consistent 22–26°C for an active, regularly fed starter. If your room is 16–18°C, your starter will still work, but it will need longer between feeds and more careful timing.

• Airing cupboard: Often 22–28°C, but can be too warm near a boiler. Check with a thermometer and move the jar to a shelf further away if needed.
• Top of the fridge: A gentle, steady warmth, often 20–24°C. Ideal for a jar that needs a little lift without overheating.
• Cool box with a hot water bottle: Place a jar of hot water beside your starter, close the lid, and you have a stable 22–25°C microclimate for hours.
• Microwave or oven with the door ajar: Put a mug of hot water inside, but only if the appliance is switched off. Never leave a starter in an oven that might be turned on.

Avoid direct radiators, sunny windowsills, and places where the temperature swings wildly. Steady warmth is more useful than a brief blast of heat.

Adjust Your Feeding Schedule for Winter

A standard 1:1:1 feed by weight, using white flour, might peak in four to six hours in summer. In a cold kitchen, the same feed can take ten to fourteen hours. You have two main options: move the starter somewhere warmer, or increase the feeding ratio so there is more food to sustain the yeast through a cool spell.

For most winter kitchens, try 1:2:2 or 1:3:3 — one part starter, two or three parts water, two or three parts flour. This gives the culture a larger buffer and slows the drop in acidity. Use water at 26–28°C. Cold tap water at 8°C will shock the starter and add hours to the rise. Warm it gently in a jug before mixing.

• Daily maintenance: At 18–20°C, feed once every 24 hours at 1:2:2. At 20–22°C and if you bake often, feed every 12 hours at 1:3:3.
• Weekly bake: Store the starter in the fridge, then take it out 24–36 hours before baking. Feed at 1:1:1, then switch to 1:2:2 every 12 hours until it bubbles and rises reliably.
• Very cold kitchen: Use 1:3:3 or 1:4:4 and a warm spot. Expect a peak in eight to twelve hours. If it peaks overnight, feed it later in the evening so it is ready when you are.

Use Wholegrains to Give Your Starter a Boost

Wholegrain flours are excellent winter allies. Wholemeal wheat, rye, spelt, and a little barley carry more minerals, enzymes, and bran than white flour, and wild yeast and bacteria love them. A spoonful of wholegrain rye in every feed can revive a sluggish starter within a day or two. It also brings a deeper flavour to your loaves, which suits hearty winter baking.

Try a winter blend: 70% strong white flour and 30% wholemeal or rye. If you use 100% wholegrain, expect faster fermentation and a thicker texture. Adjust the water to keep a thick batter or a 100% hydration starter, depending on your habit. Rye starters can be kept stiffer, around 80% hydration, and still perform beautifully. Wholegrain cookery and sourdough baking belong together in the colder months — the flour gives the starter energy, and the starter gives the grain a longer, more digestible rise.

Practical Winter Feeding Routines

• The 12-hour warm feed: Mix 20g starter, 40g warm water, and 40g wholegrain flour. Leave at 22–24°C. Feed morning and evening. It is ready when domed, bubbly, and slightly sour but not acetone-sharp.
• The 24-hour cold-kitchen feed: Mix 10g starter, 50g warm water, and 50g flour. Leave at 18–20°C. Use when it has risen by at least half and smells yeasty. This suits bakers who work long days and cannot feed twice daily.
• The fridge refresh: For occasional bakers, store the starter in the fridge. Once a week, discard all but 20g, feed 50g water and 50g wholegrain flour, leave at room temperature for four to six hours, then return to the fridge. Before baking, repeat two or three times every eight to twelve hours.

What to Do When It Still Looks Sluggish

If your starter shows no rise after 24 hours, do not panic and do not keep adding more flour. Check the temperature first. Move it to a warmer spot, stir it well, and feed with wholegrain rye or wholemeal. Use water at 27–28°C, but never above 30°C, as that can damage the culture. If a dark liquid appears on top — known as hooch — you can pour it off or stir it in. A sharp acetone smell means the starter is hungry and needs feeding more often. If you see pink, orange, or fuzzy mould, discard the starter and begin again with a clean jar.

With a thermometer, a warm corner, and a flexible feeding routine, your starter will bubble through the British winter. It may be slower than in July, but that is part of the rhythm of artisan baking. Feed it well, keep it warm, and it will reward you with reliable loaves and deeply flavoured wholegrain bread all season long.