Read the recipe instruction before you feed
| If the recipe says | What to do |
|---|---|
| “Add 100 g ripe starter” | Use an active portion at the required hydration and retain some culture for the next feed. |
| “Build the levain with starter, flour and water” | Mix those ingredients separately, then wait for the recipe’s ripeness cues before adding it to the dough. |
| “Refresh the starter, then use 120 g” | Check whether the refresh yields enough for the dough and a reserve. The recipe may be asking you to make the build in your usual jar. |
Recipes sometimes use starter and levain for the same ingredient. Look for a separate set of weights and a waiting step. Those instructions tell you whether the recipe expects a build even when the heading just says “starter”.
Follow 120 g from jar to mixing bowl
Suppose you have 50 g of refreshed mother starter and the recipe calls for 120 g of ripe levain. The recipe’s build is 20 g starter, 50 g flour and 50 g water.
| Stage | Where the grams go |
|---|---|
| Mother jar | Take 20 g for the build. Approximately 30 g stays in the mother jar. |
| Levain jar | Mix the 20 g seed with 50 g flour and 50 g water for 120 g before jar losses. |
| Mixing bowl | Add the ripe levain as directed. The mother jar remains available for the next feed. |
If you regularly leave starter on a spoon or inside the jar, plan a few extra grams while preserving the recipe’s build proportions. A clean spatula helps when you need to scrape out most of the build. Use the recipe’s readiness signs rather than assuming the levain is ready as soon as it reaches 120 g.
When a separate build is worth it
Quantity. A small mother jar may have only enough to seed a build. Growing a second jar for the bake lets you preserve the routine that has been working.
Flour. If your mother is fed white flour and the recipe calls for a whole-rye levain, feed the offshoot with the recipe’s flour. You can return to the usual white-flour feeds in the mother jar after the bake.
Timing. If you know how long the recipe’s build takes in your kitchen, you can feed it around the time you want to mix. Keep the mother on its usual schedule if the two feeds need different ratios. [1]
If the loaf needs a levain first thing in the morning, check when the recipe expects that build to be mixed. Write down the build time and the dough mixing time as two separate appointments. That leaves room to check ripeness before you commit the flour for the loaf.
Can I swap one for the other by weight?
Check flour blend, hydration and ripeness first. For example, a 100 g portion at 100% hydration contains 50 g each of flour and water. At 50% hydration, that same 100 g contains about 67 g flour and 33 g water. A straight swap would change what goes into the dough. If the recipe asks for a stiff build, follow its formula before experimenting with a substitution.
Crispy Crust’s planned bake timeline would place the mother feed and the levain build in separate steps. That makes it easier to see which jar needs checking and whether enough starter will remain after you mix.
If you’re unsure which to use, read the recipe from the mixing step backwards. Note the weight, the flour and water proportions, and what “ripe” looks like in that method. Then decide whether the jar on your counter already gives you what you need.
Use the starter feeding calculator to calculate the build you need while keeping a reserve.