Sourdough

Levain Calculator

Enter your dough weight, levain percentage, hydration, and flour blend. Get exact starter, flour, and water amounts — plus peak timing at three temperatures.
3 flour blends white, wholemeal, rye 5–30% levain percentage Peak timing at 18°C, 24°C, 28°C
Sourdough levain in a glass jar at peak — domed top with bubbles

Auto-calculates as you type

Flour blend
Mature starter 12 g
Flour to add 55 g
Water to add 55 g
Total levain 121 g
Starter 12 g Flour 55 g Water 55 g
Mature starter Flour Water

Estimated peak time — All white flour

Cool (18°C / 64°F) 8–12h
Room temp (24°C / 75°F) 5–8h
Warm (28°C / 82°F) 3–5h

Based on 10% starter inoculation at 20% levain. Wholegrain flours ferment faster — adjust timings if your blend changes. Peak is when the levain has doubled and domes at its highest.

Total levain weight is approximated from your dough weight assuming ~65% overall dough hydration. Starter inoculation is fixed at 10% of total levain weight. Adjust to match your exact formula.

Levain % by bread style

Style Levain % Hydration Notes
Baguette 20–25% 60–65% Crisp crust, open crumb — higher % for faster ferment
Country loaf 15–20% 75–100% Versatile, most recipes use 100% hydration levain
Whole wheat loaf 10–15% 80–100% Lower % offset by faster fermentation from bran
Focaccia 20–25% 100% High water levain for open, airy crumb
Overnight cold proof 8–12% 80–100% Low % slows ferment for long retard in the fridge
Sandwich loaf 15–20% 75–85% Medium % and hydration for soft, even crumb

Levain % is of total flour weight. Higher % = faster fermentation; lower % = slower, more complex flavour development.

Levain guide

Build it to peak. Mix at the right moment.

A well-timed levain is the difference between a predictable bake and a disappointing one. This guide covers how to size your levain, choose your hydration, read peak indicators, and work the levain into any bake schedule.

Standard country loaf 15–20%

Of total flour weight. Peaks in 5–8h at room temp with all-white flour.

Overnight schedule 8–12%

Lower inoculation = slower peak. Build in the evening, mix in the morning.

Rye levain boost ~25% faster

Adding 20% rye flour to the levain cuts peak time significantly in cool kitchens.

Levain % rule Levain = Flour × L%

Where L% is your levain percentage of total flour. For 800g flour at 20%: levain = 800 × 0.20 = 160g. The starter inside the levain is 10% of that (16g); the remaining 144g is split between flour and water at your chosen hydration.

01

How to use this levain calculator

Enter your final dough weight — the total weight of all ingredients in your finished dough. Set the levain percentage (typically 15–20% of total flour), your levain hydration, and your flour blend. The calculator outputs the three amounts you need to build the levain: mature starter, flour to add, and water to add. The peak timing card shows how long to expect before the levain is ready at three common kitchen temperatures.

Work backwards from when you want to mix your final dough. If you plan to mix at 9am and your levain peaks in 6–8 hours at room temperature, build the levain at 1–3am or the evening before with a smaller inoculation and cooler temperature to slow the peak.

02

What is a levain — and why build one?

A levain is a pre-ferment built fresh for each bake from a small portion of your main starter. The word levain is French for leavening agent; it describes the same thing as a pre-ferment, young starter, or stiff starter build. The key distinction is that a levain is sized for a specific recipe, timed to peak at the moment you mix dough, and used in full — nothing is saved back.

Building a levain separately from your main starter gives you several practical advantages. It lets you adjust hydration independently of your main starter (a 65% hydration levain in a recipe that normally uses 100% hydration starter, for example). It lets you use a different flour blend — adding rye to the levain to accelerate fermentation without changing your starter's character. And it keeps your maintenance routine unaffected: you can feed your starter as normal and take a small amount off to build the levain at whatever time your bake schedule requires.

03

Levain percentage — how much to use

Levain percentage is the weight of your levain expressed as a percentage of your total flour weight. At 20%, a dough made with 800g flour uses 160g of levain. Higher percentages increase the amount of active yeast and bacteria entering the dough, which accelerates fermentation. Lower percentages slow it down.

The right percentage depends on your bake schedule, flour type, and ambient temperature. For a same-day bake at 24°C, 18–22% gives you a workable window of 4–6 hours of bulk fermentation. For an overnight cold proof, drop to 8–12% to keep the dough from over-fermenting in the fridge. Whole wheat and rye loaves ferment faster because the bran carries more microorganisms, so you can reduce levain percentage by 3–5 percentage points compared to an all-white loaf.

Levain % quick reference8–12% → slow, overnight cold proof (long, complex flavour)15–20% → standard country loaf at room temperature20–25% → baguette, focaccia, same-day bake25–30% → fast bake in cool kitchen or beginner schedule
04

Levain hydration and flour blend choices

Levain hydration can differ from your main starter's hydration and from your overall dough hydration. Most country loaf recipes call for a 100% hydration levain because it peaks quickly and incorporates easily into a wet dough. Stiff levains (50–65% hydration) develop more acetic acid, produce a more complex sour flavour, and peak more slowly — they are used in pain de campagne, some rye breads, and for bakers who want more tang.

Flour blend has a significant effect on fermentation speed. Adding even 10% rye to your levain flour accelerates peak time by roughly 20–30% because rye bran contains more native yeast and bacteria than white flour. A 20% rye blend brings the levain to peak roughly 25% faster than all-white. The calculator's peak timing card adjusts automatically based on your blend selection. Use rye in the levain if your kitchen runs cold or if you want to push the peak to an earlier time without increasing inoculation.

05

Building your levain — timing it to peak

Timing is everything with a levain. The goal is to have your levain peak at exactly the moment you want to mix your final dough. The peak is the window when yeast activity is at maximum and acidity is in an ideal range — use the levain here and you get the best combination of lift, flavour, and dough strength.

The simplest approach is to build the levain the evening before a morning bake. With a 10% inoculation and all-white flour at 20–22°C, the levain peaks in roughly 10–12 hours — perfect for building at 9pm and mixing at 7–8am. In a warmer kitchen (26–28°C), reduce inoculation to 5–8% to stretch the timing. If you need the levain to peak faster, increase inoculation, use wholegrain flour, or move the jar somewhere warmer. This calculator's peak card gives you the estimated range at three temperatures so you can plan accordingly.

06

Peak indicators — how to read your levain

A levain at peak has doubled (or more) in volume, shows a domed top covered in bubbles, and has a clean, yeasty, mildly tangy smell. It should feel airy when you drag a spoon through it — light and slightly foamy, not dense or heavy.

The most reliable method is to mark the container right after building with a rubber band or tape. When the levain reaches double the starting volume and the dome is at its highest, it is at peak. Do not rely on timing alone — temperature variation in your kitchen means the actual peak can arrive an hour or two earlier or later than the estimate.

VolumeDoubled or more from the marked level right after building.
SurfaceDomed top with small bubbles; sides show a web of bubble tracks.
SmellYeasty, mildly sweet and tangy — not sharp or alcoholic.
TextureLight and airy when stirred — webs of gluten visible if you stir slowly.
Float testA small spoonful dropped in water should float.
07

Troubleshooting a slow or overactive levain

If your levain is not rising as expected, check the temperature first. Below 18°C, fermentation slows dramatically — even a healthy levain may take 14–16 hours to peak. Move the jar somewhere warmer or increase your inoculation percentage. If it is rising but with large, coarse bubbles and an alcohol smell, the levain is moving too fast and developing excess acetic acid — reduce inoculation, cool the environment, or switch to a stiff levain (lower hydration).

Poor starter health is another cause. If your main starter is not reliably doubling within 6–8 hours of a 1:1:1 feeding at room temperature, it may not be active enough to drive a good levain build. Feed your starter twice daily for two or three days before your bake to bring it back to full activity. Using a small amount of whole wheat or rye in your starter feedings can also help accelerate recovery if the culture is sluggish.

08

Fitting the levain into your bake schedule

The levain is the anchor of your sourdough schedule. Everything else — autolyse, bulk fermentation, shaping, cold proof, and baking — follows from when the levain peaks. The most common approach is to work backwards: set your target baking time, subtract your cold proof (8–16 hours), subtract shaping and pre-shaping (1 hour), subtract bulk fermentation (4–6 hours), subtract autolyse (30–60 minutes), and that gives you when the levain needs to be ready. Then count back from that moment by the expected peak time to find when to build.

For less experienced bakers, the simplest reliable schedule is: build levain at 9pm → mix dough at 7am → bulk until 1pm → shape and cold proof → bake next morning. This spreads the work across two days with no early starts. This calculator gives you the peak window at three temperatures so you can decide whether to use a cooler or warmer spot to hit your target time.

Next Steps

Use these next

Use these next based on where you are in your bake right now.

Step 1 Sourdough Starter Calculator Work out exactly how much starter, flour, and water you need for any recipe or feeding ratio. Open calculator → Step 2 Sourdough Feeding Calculator Calculate your starter feeding ratio — 1:1:1, 1:5:5, or any custom ratio — for the exact amount you need. Open calculator → Step 3 Bulk Fermentation Calculator Enter your dough temperature, starter percentage, and flour type to estimate how long bulk fermentation will take — with a live timeline and temperature reference chart. Open calculator →

Guides for this calculator

How to feed your sourdough starter Practical feeding routine for daily and weekly bakers. Sourdough starter feeding ratios Pick the right ratio for schedule, strength, and flavor. Bulk fermentation guide Use dough signs, not just clock time.

FAQs

Frequently Asked Questions

Common questions about levain builds, hydration, timing, and flour choices.

What is a levain in sourdough bread?

A levain (also called a pre-ferment or young starter) is a separate batch of starter built specifically for one bake. Unlike your main starter jar, which you maintain indefinitely, a levain is mixed fresh, timed to peak at the moment you want to mix your dough, and then used in full. Building a levain separately from your main starter gives you precise control over inoculation rate, hydration, and timing — and keeps your main starter undisturbed.

How much levain should I use in sourdough bread?

Most country loaf recipes use 15–20% levain as a percentage of total flour weight. Higher percentages (20–25%) ferment faster and suit same-day bakes. Lower percentages (8–12%) ferment slowly and are better for long overnight cold-proof schedules. The style of bread matters too: baguettes tend to use 20–25%, whole wheat loaves use 10–15% to compensate for the faster fermentation from bran, and focaccia uses 20–25% for a quick open crumb.

What is the difference between levain and starter?

Your starter is the ongoing culture you feed and maintain. A levain is a portion of that starter mixed with fresh flour and water to create an active, peaked pre-ferment sized for a specific recipe. Think of the starter as a bank account and the levain as a withdrawal you make before each bake. The levain is built to peak at baking time and is added in full to the dough. The starter stays in the jar for next time.

How long does it take for levain to peak?

At room temperature (24°C / 75°F), a typical levain with 10% inoculation and all-white flour peaks in about 5–8 hours. At a cool 18°C it takes 8–12 hours; at a warm 28°C it peaks in 3–5 hours. Adding wholemeal or rye flour speeds fermentation because the bran carries additional native yeast and bacteria. The peak timing card in this calculator adjusts automatically based on your flour blend selection.

Can I use wholemeal or rye flour in my levain?

Yes — and many bakers do. A small amount of wholemeal or rye flour (10–20% of the levain flour) accelerates fermentation significantly because the bran and germ carry more native microorganisms than white flour. An 80/20 white-rye levain typically peaks 25–30% faster than an all-white levain at the same temperature. This is useful if your kitchen is cool or if you want to push the peak to an inconvenient time. This calculator adjusts peak estimates for all three flour blend options.

What happens if I use levain past its peak?

Past-peak levain has converted most of its available sugars and the yeast activity is declining. Using it in dough can produce a less active ferment, a flatter loaf, and more pronounced sour flavour because the acetic acid produced after peak continues to accumulate. It is not a disaster — especially if only slightly past peak — but for best results, mix your dough when the levain domes at its highest and begins to just show the first signs of sinking at the edges. Plan your build time backwards from when you want to mix.

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