Understanding Sourdough Starter Peak Timing

What is Peak?

Peak is the point when your starter has reached maximum fermentation activity. At this moment:

• Yeast population is at its highest
• CO2 production is maximum
• The starter has the most leavening power
• It's the ideal time to add to your dough

Visual Signs of Peak

Volume

• Doubled or tripled from original size
• At maximum height before falling
• May show stretch marks on sides of jar

Surface

• Domed or slightly domed top
• Active bubbles on surface
• Just beginning to flatten indicates you're at or just past peak

Texture

• Light and airy throughout
• Filled with bubbles of various sizes
• Stringy or web-like when stirred

The Peak Window

Peak isn't a single moment but a window of time:

• Early peak: Just reached maximum, dome still rising
• True peak: Maximum volume, dome at highest point
• Late peak: Dome flattening, still very active
• Past peak: Falling, starting to deflate

Usable Window

For most baking, your starter is usable from early peak through late peak. This window typically lasts:

• 1-2 hours at room temperature
• Longer in cooler conditions
• Shorter in warm conditions

Testing for Peak

Float Test

1. Fill a glass with room temperature water
2. Gently drop a small spoonful of starter on surface
3. If it floats, it's ready
4. If it sinks, wait longer or feed again

Visual Observation

Watch your starter after feeding:

• Note when it starts rising
• Mark the level with a rubber band
• Check every hour as it approaches expected peak
• Use when at or near maximum height

Factors Affecting Peak Time

Temperature

Feeding Ratio

• 1:1:1 - Peaks faster (4-6 hours typical)
• 1:2:2 - Medium timing (6-8 hours)
• 1:5:5 - Slower peak (10-14 hours)

Starter Strength

• Young starters peak slower and less predictably
• Mature starters have consistent, reliable timing
• Neglected starters may take multiple feeds to regain predictability

Planning Your Bake Around Peak

Backward Planning

Know when you want to mix your dough, then work backward:

1. Determine your mixing time (e.g., 9 AM)
2. Know your starter's typical peak time (e.g., 6 hours)
3. Feed your starter at the right time (3 AM for 9 AM use)

Evening Feed for Morning Bake

Most common schedule:

• Feed starter before bed (10 PM)
• Starter peaks while you sleep
• Use first thing in the morning (6-8 AM)

Morning Feed for Afternoon Bake

• Feed starter early morning (6-7 AM)
• Starter peaks midday
• Mix dough early afternoon

What If You Miss Peak?

Slightly Past Peak

Still usable but may result in:

• Slightly more sour flavor
• Potentially slower rise in dough
• Usually fine for most recipes

Significantly Past Peak

If starter has collapsed significantly:

• Feed again and wait for new peak
• Or use for discard recipes
• May still work but results less predictable

Common Peak Timing Mistakes

Using Too Early

• Starter hasn't developed full leavening power
• Dough may rise slowly or insufficiently
• Solution: Wait for proper doubling and float test

Using Too Late

• Yeast has consumed most food
• Acids are higher, flavor may be too sour
• Rising power diminished
• Solution: Feed more often or adjust timing

Inconsistent Timing

• Peak becomes unpredictable
• Hard to plan baking
• Solution: Feed at consistent times and temperatures