Know Exactly When Your Starter Peaks

Stop guessing. Use science-backed estimates to catch your sourdough starter at its most active moment — every single time.

Predict My Peak

Peak Time Estimator

Enter your kitchen temperature and feeding ratio. We'll calculate the optimal window when your starter is bubbly, domed, and ready to leaven bread.

°C
Typical kitchen range: 18–28°C

How We Predict the Peak

Temperature Drives Activity

Yeast and bacteria in your starter are living organisms. Their metabolic rate doubles roughly every 8–10°C increase. A starter at 26°C can peak twice as fast as one at 18°C. Our model uses an exponential temperature curve calibrated from hundreds of baker observations.

Feeding Ratio Sets the Pace

A 1:1:1 feeding gives the starter a small meal — it peaks quickly, often in 3–5 hours. A 1:5:5 ratio provides a large food supply, stretching the rise to 10–14 hours. We adjust baseline times proportionally and factor in the lag phase before exponential growth begins.

Observable Signs Confirm It

The calculator gives you a target, but always double-check: look for a domed surface, bubbles throughout, a pleasant tangy aroma, and a sample that floats in water. These physical cues validate that your starter is at peak vigor and ready to lift your dough.

Pro Tips for Consistent Results

Use a Consistent Feeding Schedule

Feed your starter at the same time daily. A predictable routine builds a strong microbial community that behaves reliably. If you change feeding times, give the starter 2–3 days to adjust before expecting accurate peak predictions.

Measure Temperature at Starter Level

Your kitchen counter might be cooler than the room thermostat reads. Place a thermometer next to your starter jar for the most accurate input. Even a 2°C difference can shift the peak by 30–60 minutes.

Track and Adjust

Keep a simple log of temperature, feeding ratio, and actual peak time for a week. Use that data to fine-tune your expectations. Every starter has its own personality — this tool gives you a baseline, and your notes make it personal.

Frequently Asked Questions

What if my starter peaks earlier than predicted?
Warmer microclimates (near an oven, on top of a fridge) can accelerate activity. Measure temperature right at the jar. If your starter consistently peaks early, try reducing the input temperature by 1–2°C in the calculator to better match your actual conditions.
Can I use this for a stiff starter (low hydration)?
This predictor is calibrated for 100% hydration starters (equal weights flour and water). Stiff starters ferment more slowly. As a rough guide, add 20–30% to the predicted time for a 60–65% hydration levain.
Does flour type change the timing?
Yes. Whole-grain rye and whole wheat ferment faster than all-purpose white flour due to higher enzyme and nutrient content. If you feed with 100% whole grain, the peak may arrive 10–20% sooner than predicted.