This is one of the most common sourdough frustrations because the fridge doesn't actually stop fermentation—it just slows it down. Whether your loaf continues to rise significantly in the fridge depends on several variables that can change from bake to bake.

Why some loaves rise in the fridge and others don't?

1. The dough temperature going into the fridge

This is usually the biggest factor.

• If the dough is warm (24–28°C) when it enters the fridge, fermentation continues for several hours before the dough cools down.
• If the dough is cool (20–22°C), fermentation slows much sooner and you may see almost no additional rise.

A loaf entering the fridge at 27°C can easily gain 20–50% more volume overnight compared with one entering at 21°C.

Correction: Measure dough temperature at the end of bulk fermentation and aim for consistency every bake.

2. How far bulk fermentation progressed

If you under-ferment bulk:

• The loaf may continue rising substantially in the fridge.

If you fully ferment bulk:

• The loaf may appear almost unchanged in the fridge because most of the gas production already occurred.

Many bakers accidentally use the fridge as part of bulk fermentation on some bakes and as purely a cold retard on others.

Correction: End bulk at a consistent level of expansion (for example 40–60% increase for many white sourdoughs, depending on dough strength and temperature).

3. Your fridge temperature varies

Many home fridges fluctuate between 2°C and 8°C depending on:

• Shelf location
• Door openings
• Load of food
• Defrost cycles

A dough at 7–8°C will continue fermenting much more than one at 3–4°C.

How to correct this:

• Place a thermometer where the dough sits.
• Aim for 3–5°C.
• Use the back of the fridge rather than the door.

4. Starter strength and inoculation percentage

If one dough contains:

• 15% starter

and another contains:

• 25% starter

the second will often keep fermenting more aggressively during the first hours of refrigeration.

Similarly, a very active starter can create more fridge rise than a sluggish one.

How to correct this: Keep inoculation and starter maturity consistent.

5. Dough composition

Higher:

• Hydration
• Whole grain content
• Rye percentage

usually means faster fermentation.

A 20% whole wheat loaf may continue rising in the fridge while a white loaf made with the same schedule barely moves.

How to decide what you actually want

If you want the loaf to rise noticeably in the fridge

• End bulk slightly earlier.
• Put the dough into the fridge a little warmer.
• Use a slightly higher levain percentage.
• Keep fridge temperature around 4–5°C.

If you want almost no rise in the fridge

• Complete bulk fermentation before shaping.
• Chill the dough quickly.
• Use a colder fridge (2–3°C).
• Avoid leaving shaped loaves on the counter before refrigeration.

A simple diagnostic

On your next bake, write down:

1. Dough temperature at end of bulk.
2. Percentage rise during bulk.
3. Fridge temperature.
4. How much the dough expands overnight.

After 2–3 bakes you'll usually find one variable is driving the inconsistency.

For example, many home bakers discover that a loaf that rises a lot in the fridge was actually shaped at 27°C after a long warm bulk, whereas the loaf that didn't rise was shaped at 22°C and cooled much faster.

Fingers crossed this sheds a bit of light for you all :)

Jan and Eric