How to keep your starter culture active and healthy
When do I need to feed my starter?
You can keep your starter in a container on your counter and feed it at least once per day. You can feed it as often as every four hours, and the more often you feed it, the more active it will be.
You can also keep your starter in your refrigerator. Being refrigerated slows down the starter’s growth, so it only needs to be fed every week or so.
You can tell if your starter is active enough to bake with when you can put a spoonful of it in water and it floats. My starters are most active about four hours after feeding, so if they don’t pass the float test I feed them and then check again in four hours.
You should plan ahead and feed your starter several times 4-12 hours apart before you bake to make sure it will be active enough, and to make sure that you will have enough starter for the recipe you’re planning to make.
Oh no, I forgot to feed my starter!
Don’t worry! Sourdough starter is made of yeast and bacteria that manage to survive in the wild without being fed every day. They’ll be fine for a long time without being fed, it just might take a couple of feedings before they’re active enough to bake with. Yeast and bacteria can go dormant when lacking food, and yeast has been known to survive in this state for over 250 million years – so you’ll have to miss quite a few feedings to kill your sourdough starter.
If you don’t feed your starter for a while it will make a layer of brown liquid, called “hooch”. If there’s a lot of it you should pour it off before feeding again.
How do I feed my starter?
“Feeding” a sourdough starter means adding flour and water to it to provide food for the yeast and bacteria living in it. Make sure to use chlorine-free water to avoid harming your starter. I use regular all-purpose flour for my starters. You can experiment with feeding them other types of flour as well, which might cause them to develop different flavors.
Some recipes will specify a certain volume of starter (like 1 cup), while some specify a certain weight (usually in grams).
Because your starter will be bubbly, it’s usually better to measure by weight. In my experience, 1 cup of well-fed starter weighs anywhere from 120g to 220g, but many recipes will specify a different weight. If possible, always follow the weight specified on the recipe.
With that in mind, it’s best to feed your sourdough starter by weight, but if you can’t, you can still do it by volume.
Feeding by weight
Always add equal parts by weight of water and flour to your starter, then mix it thoroughly.
If you’re feeding to maintain your starter, or growing it so that you can use it in a recipe, it’s best to do equal parts sourdough starter, water, and flour. For example, if you have 30g of sourdough starter, you should add 30g of flour and 30g of water. Every time you feed your starter like this, its weight triples.
If you’re feeding your starter up to make a recipe and you don’t need to triple it, you can feed it less. If you had 500g of starter and needed 1000g, instead of feeding with 500g of flour and 500g of water you could feed with 250g of flour and 250g of water instead – but always make sure to feed equal parts flour and water!
Feeding by volume
When feeding by volume, always add two parts flour for every one part water, then mix it thoroughly.
If you’re feeding to maintain your starter, or growing it so that you can use it in a recipe, it’s best to do one part sourdough starter, one part water, and two parts flour. For example, if you have 1 cup of sourdough starter, you should add 1 cup of water and two cups of flour. Every time you feed your starter like this, its volume triples.
If you’re feeding your starter up to make a recipe and you don’t need to triple it, you can feed it less. If you had 1 cup of starter and needed 2 cups, instead of feeding with 2 cups of flour and 1 cup of water you could feed with 1 cup of flour and 1/2 cup of water instead. Just make sure that you’re feeding your starter two parts flour and one part water.
Discarding starter
Since your starter grows every time you feed it, it’s necessary to discard some of it. If you started with one cup of starter and fed it daily without discarding any for two weeks, you would end up with enough starter to fill up an Olympic-sized swimming pool!
If you’re just maintaining your starter, you can keep a set amount and discard the rest. I discard all but 30g (about 2 tablespoons) of starter and then feed it.
If you don’t like wasting starter when you discarding it, there’s lots of great recipes that can use your discarded starter!
Re-hydrating dried starter
If you’ve received some dried sourdough starter, you’ll need to re-hydrate it before you start feeding it.
Re-hydrating sourdough starter is easy. Start by putting some dried starter in a container of your choosing, then add enough water to cover the dried starter. Stir this occasionally until it’s all dissolved (This usually takes an hour or two). Once it’s dissolved, you can start feeding it. It will probably take a few feedings before it’s active enough to bake with.
Sourdough starter tips
- If you’re not planning on baking with it, keep a small amount of starter (a few tablespoons, or ~30 grams) so that you don’t waste too much flour while feeding it.
- The warmer it is, the faster your starter will grow. The ideal temperature is about 70-80°F (20-25°C). If you get your starter too hot (more than ~120°F/50°C) you risk killing the yeast growing in it.
- If you want to store your starter for a long time or send it in the mail, you can dry it out by spreading a thin layer on parchment paper.
- Keep your sourdough starter covered so that it doesn’t dry out.