Sourdough · Calculator

Sourdough Starter Manager

Log a feed, see when your starter should peak, record when it actually did, and the timing becomes your own.

Start calculating Read the guide
Two jars of sourdough starter marked with rubber bands at their fed and peak levels

How to use the starter manager

One feed at a time, in the order you do it at the bench.

  1. 1

    Log the feed. Pick the ratio, set the starter temperature, and log it when you feed. Put a rubber band at the level.

  2. 2

    Watch the clock, not the calendar. The jar and chart show where it should be now and when the peak window opens. Add the reminder to your calendar if you will be away.

  3. 3

    Record the peak. When the rise stalls and the dome starts to flatten, tap “It’s peaking now”, or enter when it did. Add how high it got if you marked it.

After two recorded peaks at a ratio, the expected time is your starter’s own.

3D · Your jar Drag to rotate · Scroll to zoom
Time elapsed0 h
Modeled rise0%
StageAfter feeding
0.0 h

Experiment with conditions

Feeding ratio (starter : flour : water)
78°F

Use the temperature of the starter itself when known. It may differ from room temperature.

Feeding your starter for real?

Log it with the ratio and temperature above, and the jar follows your feed live.

Need the grams? Feeding calculator
Important: This is an evidence-informed teaching model, not a prediction for your particular starter. A rise of 100% means twice the initial height. Different starters may rise more or less.

Your feeds

Log a real feed above. Each recorded peak shows up here and on the chart, so you can see how your starter behaves.

Your journal stays in this browser. When you save a peak, an anonymous copy (ratio, temperature, hours to peak and rise, with no notes, name or email) helps improve our timing estimates, as the privacy notice explains.

Starter tracking guide

Learn your starter, one feed at a time.

Every starter keeps its own clock. Log your feeds and peaks here and the expected time moves from our general estimate to your jar’s real timing.

How we calculate: Sourdough methods

Use these reference values to interpret your results

  • Log

    Each feed

    Ratio, starter temperature and the time you fed, saved in this browser and emailed to you when you ask.

  • Watch

    The window

    Where the rise should be now, and when to check the jar.

  • Learn

    Your timing

    After two recorded peaks, the expected time is your starter’s own.

Expected peak

your median, else the table

Until you have two recorded peaks at a ratio, the window comes from our starter timing table at your starter temperature. After that, it is the median of your own peaks.

Reading the jar

The chart’s curve is an illustration of that sequence, scaled to your expected peak. The real shape depends on flour, hydration and the jar, which is why the points you record matter more than the line.

After feedingFlat top, few new bubbles. Band at the level.
Activity buildsSmall bubbles on the glass and the first rise above the band.
RisingMore bubbles, clear height gain, a rounded top.
Near peakHigh, bubbly and domed, or just starting to level. Use it now.
After peakFlatter or sunken top, with a residue line above the level. Still alive; feed it again.

Why your own timing beats any table

Planning estimates for an established, healthy 100% hydration wheat starter, not one in its first two weeks. The 1:1:1 and 1:2:2 rows bracket what King Arthur Baking saw at about 78°F, checking every 4 hours; the other cells are our extrapolations. Doubling, the highest point and the first fall are separate moments, and your own starter will vary, so mark the jar and learn its timing. The source behind our table is King Arthur Baking, sourdough feeding ratio comparison (2025).

Two starters fed the same ratio in the same kitchen can peak hours apart. Recording a few feeds at a steady temperature tells you more about your jar than any chart, and it makes bake-day planning simple: feed at the time that puts the peak where you need it.

FAQ

Starter manager questions

How the expected peak is worked out, where your feeds are kept and how to keep a copy.

How does the starter manager work out when my starter will peak?
At first it uses our planning table, the same one every sourdough page on the site reads: for example 6–10 hours for a 1:2:2 feed at 75°F / 24°C. Once you have recorded two peaks at a ratio, it switches to the median of your own peaks, because your flour, jar and kitchen matter more than any table.
What counts as the peak?
The highest point the starter reaches before it stops rising and the dome starts to flatten. It is a practical cue for when to use the starter, not a measurement of the yeast. Doubling often comes earlier, and some healthy starters top out below double.
I missed the peak. What should I record?
If you saw it, choose “Earlier” and enter roughly when. If you only found it already falling, use the residue line on the glass and your best guess, or remove the feed so a guess does not skew your average.
Where are my feeds saved?
Your feed journal stays in this browser, on this device. Clearing your browser data or using a private window removes it, and it does not follow you to another device. When you save a peak, an anonymous copy (the ratio, starter temperature, hour you fed, hours to peak and rise, with no name, email or notes) is stored to improve our timing estimates, as the privacy notice explains.
Can I keep my log if I clear my browser?
Yes. Under your feeds, enter your first name and email and choose “Email me my log”: every feed and peak arrives as a printable PDF. If you also tick “Check in with me about my starter in a week”, we save your log, send you one email a week later using your own numbers, and add you to our marketing list. You can unsubscribe at any time.
Does temperature change the expected time?
Yes. A 1:1:1 feed is roughly 6–10 hours at 68°F / 20°C, 4–6 hours at 75°F / 24°C and 2–4 hours at 82°F / 28°C in our table. Between those columns the manager blends the two nearest estimates. There is no fixed rule per degree, so record the temperature with each feed and let your own peaks take over.
How do I get the amounts for a feed?
Use the sourdough feeding calculator for the grams of starter to keep, flour, water and discard. The manager tracks timing; the feeding calculator does the weighing.

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