Why Won't My Sourdough Starter Rise? (And What to Do When the Kitchen Gets Cold)

A starter that won't rise is almost always cold, hungry, or still young, and all three are fixable. Move the jar somewhere around 70 to 75°F, feed it fresh flour and water, and give it a few days of regular feedings. In my book I say a sluggish starter usually isn't getting enough nutrients or is struggling in its environment, and as the weather turns, that environment is usually your kitchen.

The usual causes, most likely first

When I first began, I had two starters and absolutely no idea what I was doing. My book even includes a picture of what kept happening to me. So I've stared at a flat jar more than once, and the causes below are the ones I'd check, in the order I'd check them.

Your kitchen is cold

Starters thrive in a warm spot around 70 to 75°F; on top of the fridge works. We keep our place pretty warm, usually around 76 degrees in the daytime and 70 at night. Once the heat comes down for the season, your counter may sit well under that range, and a cold jar rises slowly or looks like it isn't rising at all.

So give it more time before you decide anything. If you feed it and it's slow, a warmer spot (the cold kitchen plan below) is the first thing to try.

It's hungry

A starter that has used up its food gets sluggish. Two signs I look for are grey liquid on top (hooch) and a smell like nail polish remover. My book says that smell means your starter is starving and producing too much acid, so feed it more often, try twice a day for a while, and discard some starter before each feeding. If you want the full picture of what each smell and layer means, the is my sourdough starter dead? post walks through them.

If your starter lives in the fridge like mine does, a flat jar straight out of the cold may just need to warm up. Whether it needs a feed depends on when it went in, and the fridge storage post covers that.

It's still young

My book's starter schedule runs seven days, and the early days can look quiet. The schedule even tells you to feed every 24 hours at first and switch to every 12 once bubbles show up. If you're in your first week or two, you may be looking at a starter that's still getting going. I'll say it the way the book does: if you mess up, don't get discouraged, you can always start again.

Your water has chlorine

There are only two ingredients in a starter, so the water matters as much as the flour. Filtered water is best because it removes chlorine, which can slow down or stop your starter's activity. Tap water often contains chlorine or chloramine. If tap is your only option, let it sit uncovered for 24 hours so the chlorine can dissipate.

Your flour needs a boost

Whole wheat and rye are both packed with nutrients that boost yeast activity. If your starter has been eating only white flour and has gone quiet, swapping in whole wheat or rye for a few feedings gives it a push. The rye flour starter post goes into why rye works so well.

A cold kitchen plan for November

Here's what I'd do the day the kitchen turns chilly.

First, try the oven. If you keep your home on the cooler side, my book suggests keeping your starter in the oven with the oven turned off. I've even turned the oven light on for just a little added heat. The most important part is to take the jar out BEFORE you turn the oven on. I've seen and heard many horror stories, and a sticky note on the oven door is an easy way to remember.

Second, use warmer water. The warmer the water, the faster the starter rises. 85 degrees is what my recipe uses while you're building a starter, and you shouldn't go over 90 to 100 degrees because that could scorch your flour. A thermometer takes the guessing out of it, and it's one of the tools I use in my own baking.

Third, give it time. Cold slows everything down, so a feeding that would have doubled in 6 to 8 hours in a warm kitchen may need longer. Check back before you worry.

A revival plan for the next few days

If your starter has gone flat and there's no mold, my revival steps are simple.

1. Discard most of the starter, keeping 15 to 30g.
2. Feed it 100g of room temperature water, 70g of bread flour and 30g of rye flour, stirred together with the starter.
3. Repeat every 12 hours for several days, until the starter doubles in size and smells tangy.

Use whole wheat or rye for a few of those feedings if it's really quiet, keep the jar somewhere warm, and be patient. The feeding post has the full routine once it's rising again. Starters can take a few days to bounce back. I've also kept a starter on the counter for close to a week without feeding it, and it was absolutely fine after a feeding or two. They're sturdier than they look.

How to tell it's working

Put a rubber band around the jar at the level of the starter right after you feed it. Then you can see the rise instead of guessing. Healthy looks like bubbles, a rise and fall that repeats, and a tangy, yeasty, slightly sour smell. Once your starter is bubbly and has doubled, usually 6 to 8 hours after a feeding depending on temperature and hydration, it's ready to bake with. My book also has a float test: drop a little in water, and if it floats, it's active.

When to start over

Mold is the only reason I'd throw a starter out. If you see it, toss the starter, wash and sanitize your jar thoroughly, and begin a fresh batch. Anything short of mold, keep feeding. I've killed several starters myself, and the lesson from my book still holds: you can ALWAYS start again.

Quick answers

How long does it take a starter to rise in a cold kitchen? It may take longer than the usual 6 to 8 hours, so check it a few hours later than you normally would before deciding it's stuck. A warmer spot speeds it up.

Can I put my starter in the oven to keep it warm? Yes, with the oven turned off. Turning the oven light on adds a little heat, and the jar must come out before you preheat.

Does my starter need rye or whole wheat flour? A few feedings of either can give a quiet starter a boost, since both are packed with nutrients.

How many days until I should worry? Give it a few days of feeding every 12 hours before you decide anything. Starters can take that long to bounce back.

Bake it anyway

Sourdough has taught me a heck of a lot about patience, grace, and laughing things off when they don't go as planned. A slow, sulky starter still makes bread once it wakes up, so give it warmth, food and a few days. Then bake it anyway.

If you'd like the whole thing on your fridge door, the "Is My Starter Okay?" cheat sheet is $5.99 in my Etsy shop (linked here), and it matches what your jar is doing to the cause and the fix without scrolling ten forums.