Lately I’ve been doing a lot of “remote” sourdough starter troubleshooting. It began a few months ago, when I encouraged my distant friend Jess to start baking sourdough bread for the first time. She got her hands on a starter locally and began working with my no-knead pain au levain recipe. For reasons I cannot yet fully explain, the starter—which came from a wonderful bakery, famous for its crusty sourdough loaves—refused to behave for her like it clearly did for them.
Jess texted me pictures of compact, tight-crumbed loaves that did not look anything like mine. Over the past few months, I’ve been working with her to improve things, and we have definitely been making progress:
Going from the loaf on the left to the loaf on the right has come thanks to a number of adjustments, both to Jess’s starter itself, which we put through a rigorous and intense feeding routine, and to her approach to proofing and baking.
Meanwhile, another faraway friend—Ashleigh—texted to say that she was all of a sudden finding that her loaves were not proofing, after many months of otherwise gorgeous results. In her case, the solution was a little more straightforward: Up until recently, her balmy Mississippi kitchen had kept her doughs happy. But when the recent cold snap hit the Southern U.S., things slowed way down. Getting her back on track mostly involved just finding a warm spot to proof her levain, which in her case was an (off) microwave oven and some insulating kitchen towels:
Once her starters perked up, her breads did too.
All this starter troubleshooting made me realize that it would be a good idea to revisit the subject here, since it was clear that I hadn’t said all there was to say about how to keep your starter happy and healthy (or get it there if it isn’t now).
As it turns out, I have lots left to say on the subject.
A healthy starter, refreshed at a high inoculation rate—i.e., 25-100% starter relative to flour and water—should triple in volume and then collapse after 8 to 12 hours at 76˚F. The goal is always to use a levain (in a dough, or to make more levain) or slow it down (for long term storage) while it is on the way up, so that it has lots of upward momentum left in it, so to speak. Which means that you want to “catch it” when it has about doubled in volume. With a healthy starter, that should take between 4 to 6 hours at 76˚F.
Temperature and levain proofing
A levain is no different than a dough when it comes to its “preferred” temperature range. If you mix your levain using cold water and/or proof it at temperatures much below 75˚F, then it is going to slow down. And slow down significantly—the curve for microbial growth relative to both time and temperature is closer to exponential than linear, which means that a starter that doubles in volume in 4-6 hours at 75˚F might take twice as long to double at 65˚F. Ditto for higher temperatures: At 85˚F, it’s likely to double in just an hour or two.
Another consequence of that exponential growth curve is that things tend take a long time to get going, but they happen fast once they do. Which is why a starter (or loaf) can seem to just sit there for a long time, but expand rapidly once it shows signs of life. (I often get panicked messages from people who say their loaves are not rising. Usually I tell them just to wait a little longer, especially if the kitchen is cold, and most of the time that does the trick.)
Of course we use this fact to our advantage. It’s why a levain that has just about doubled in volume can be moved to the fridge and held in a state of suspended animation for at least a week without much loss in leavening potential. And it’s why you can mix and proof a levain for baking at 85˚F and have it ready for use in half the time it would take at 75˚F. (I don’t recommend doing the latter unless you know what you are doing, mind you.)
The bottom line is that you should do your best to pay attention to the temperature at which you mix and proof your levain if you want it to remain happy and behave appropriately. (If you need a refresher on Desired Dough Temperature and how to set it, see this post.) And, as always, remember to use your eyes above all: if your levain hasn’t at least doubled in volume, then don't move it along yet, or your bread is not going to rise.
As for how to control the temperature of your starter while it proofs: I use a temperature-controlled proofing box for my levain and for my doughs, because I have it. But since a levain doesn’t take up much room, you could get away with a simpler setup: Just mix it at the appropriate temperature and put it into a thermal lunch box or similar container, alongside a sealed deli container of warm (~80˚F) water to keep it there. (Or use your microwave like Ashleigh did.)
Reviving a flagging starter
This method is designed to restore a starter that has lost some of its vigor, for whatever reason. (This is a more formal approach to the one I recommended to Jess and Ashleigh.) The idea here is to do a rapid series of room temperature refreshments until the starter is back to full health, after which point it should make beautiful breads and can be cold-stored again.
Because this requires multiple refreshments, it can be done on a small scale to conserve flour. The goal of the schedule is to maximize feedings while keeping the timing reasonable (i.e., avoiding having to wake up in the middle of the night to tend to it), which means two “fast” refreshments during the day, and a “slow” one while you sleep. And it includes ~5% rye flour for a bump in nutrition.
Ideally you should be precise about the temperature at which you mix and proof the starter here, so that everything moves on the right schedule. At the very least, use water that is slightly above the DDT numbers listed below, which will get it close.
At each stage, the starter should at least double in volume before you move onto the next one. If it does not, let it go longer and skip to the next one. (Remember that exponential growth curve: It’s generally better to let a starter proof too long than to refresh it before it is ready, otherwise you risk diluting the bacteria and yeast you are trying to cultivate.) Hopefully you won’t need to keep up these thrice-daily refreshments for more than a few days.
I have to credit Kristen Dennis, aka Full Proof Baking, for this approach. She recommends this schedule for feeding a healthy levain to supercharge it for baking; while I don’t think that’s absolutely necessary with a healthy starter, at least using the recipes I do, it was easy to see how her method would be the perfect way to bring a less-than-vigorous starter back to life.
Note: 1.5g rye flour is about 1/2 teaspoon, and you don’t need to measure more accurately than that.
Morning (~7am, 1:1:1, 76˚F DDT): 25g bread flour/1.5g rye flour/25g water/25g starter
Afternoon, (~2pm, 1:1:1, 76˚F DDT) 25g bread flour/1.5g rye flour/25g water/25g starter
Overnight feeding (~9pm, 5:5:1, 70˚F DDT) 25g bread flour/1.5g rye flour/25g water/5g starter
Repeat this schedule until the starter seems to be picking up steam (i.e., doubling within the first 6-8 hours), which might take 2 or 3 days. Then move on to phase 2.
Morning (~7am, 2:2:1, 76˚F DDT): 25g bread flour/1.5g rye flour/25g water/12g starter
Afternoon, (~2pm, 2:2:1, 76˚F DDT): 25g bread flour/1.5g rye flour/25g water/12g starter
Overnight feeding (~9pm, 5:5:1, 70˚F DDT): 25g bread flour/1.5g rye flour/25g water/5g starter
Repeat this schedule daily until the starter clearly doubles in 4 to 6 hours time. At this point, you can refresh it one last time at a larger scale using the usual 2:2:1 ratio and store it in the fridge, as described below.
Refreshing a healthy levain for occasional use or cold storage (100% hydration)
This one should be second nature to most of you by now, but this is how I maintain my starter most of the time, since I only bake a few times a week, at most. It’s also how I prepare larger quantities of levain for baking; in those cases, I mix it into a dough rather than move it to the fridge once it has doubled in volume.
It’s scaled for a quart deli container or jar and to give me enough starter for my regular bakes. It can be scaled up or down if desired, of course.
Most of the time, do your best to get the levain temperature to 76˚F by adjusting the water temperature (remembering that the seed starter from the fridge is cold).
During times of temperature extremes, adjust the levain temp up or down. If your kitchen is above 85˚F, set it to 65˚F or so. If it’s well below 70˚F, aim for 85˚F or so.
You want to the levain to be covered well to prevent drying out, but still able to breathe. If using a mason jar, invert the lid; if using a deli container, poke a small hole in the lid with a thumbtack.
150g high-protein AP or bread flour
Combine flour, water, and starter (return remaining starter to fridge as a backup in case of disaster) in a bowl and stir until uniform. Transfer to a clean, tall, and straight-sided container and cover. Mark starting level with rubber band or marker. Proof at at 76˚F until doubled in volume, 4 to 6 hours.
Transfer to refrigerator and store for up to 14 days before refreshing again. (Cold-stored levain is generally best used for baking within 7-10 days.)
Refreshing a healthy levain overnight for use in bread the next morning
If I need some levain for a dough I want to mix in the morning, I’ll either make it as described above and put it into the fridge overnight, or—if it’s too late to do so before heading to bed—I’ll just make it in the evening using a 20:20:1 ratio (i.e., 100% flour, 100% water, and 5% levain) and leave it out at room temperature. If ambient temps are very warm, I’ll set the DDT to 65˚F or so.
Converting a liquid (100% hydration) starter to a stiff (50% hydration) starter
This one is for future reference. I’ve been doing a lot of work lately with a stiff, or low hydration, starter, because it is one key to reliably making sourdough breads that aren’t sour, something I consider essential for sweet, enriched breads like brioche and challah, along with the sourdough bagel recipe I shared with newsletter subscribers a few weeks ago. There’s much more to the technique that I will explain soon, but step one is reducing the amount of water in your starter.
I now keep both a stiff and liquid starter in the fridge, and feed both of them at least once a week. (In case you are wondering why I don’t just use a stiff starter for all my breads, there are a few reasons, but the simplest one is that mixing a stiff starter is work, precisely because it is stiff. You can’t just stir it together—it actually requires kneading to mix uniformly.)
Mix 100g bread flour, 37g water, and 50g 100% hydration starter in a bowl and stir until it starts to come together. Aim for a DDT of 76˚F.
Tip the contents of the bowl onto a lightly-floured countertop and knead by hand until it’s uniform, 30 to 60 seconds.
Transfer to a covered container and allow to proof at 76˚F until doubled, 4 to 6 hours, then use or refrigerate for up to 14 days.
Once you have a stiff starter, you can refresh it in the usual way, e.g.:
Mix 150g bread flour, 75g water, and 75g stiff starter (2:1:1) in a bowl, and then knead on a lightly-floured countertop until uniform. Aim for a DDT of 76˚F.
Transfer to a covered container and allow to proof at 76˚F until doubled, 4 to 6 hours, then use or refrigerate for up up to 14 days.
I’m sure that there’s more to say on the subject of starters and levains, but I’ll leave it there for now. Let me know if you have questions or want me to go into other aspects of this subject.