Top 5 Sourdough Questions:

1. Why do I have to discard some of the starter every time I feed it?

The answer is a mathematical one.

Because the amount of flour and water we feed the starter must always be at minimum equal to or greater than the starter itself, the starter would grow exponentially with each feeding if we did not discard a portion of it.

For example, if on Monday, we feed a 20 gram starter with 20 grams of flour and 20 grams of water, then on Tuesday, if we didn't discard, we'd be feeding a 60 gram starter with 60 grams of flour and 60 grams of water, and on Wednesday, a 180 gram starter with 180 grams of water and 180 grams of flour...you can see where this is going.

Things would very quickly get out of hand.

2. What can I do with the discard?

Now, I hate food waste as much as anyone, and I know that pouring off that discard can be painful.

I minimize the waste in a few ways:

First, I keep a very small starter. You don’t have comb the internet very long to find that sourdough starters can be large sloppy wet messes. These starters are likely being fed a ratio of 1:1:1. According to this ratio, a 50 gram starter, for example, would be fed 50 grams of flour and 50 grams of water. This method has works just fine, but I’ve been experimenting with and becoming more and more convinced of the dry starter method.

A dry starter is a very small starter, and it’s fed at a ratio of 1:5:5. For example, 10 grams of starter is fed with 50 grams of flour and 50 grams of water. This is a small, tidy, and manageable starter, and I love it!

When I want to bake, I use nearly all of this small starter to build the volume of leaven the recipe calls for (more on this below) and just make sure that there’s a tiny bit of starter left in my jar—a teaspoon will do—to feed and keep.

When I'm not planning to bake for a few days, I keep my starter in the fridge. This cuts the required feedings down from daily to once a week or so. Sometimes, when I want to bake just a loaf or two, I’ll pull the starter from the fridge, scoop out a teaspoon of starter to build up with a few feedings, and put the rest right back into the fridge. This saves me from needing to feed an entire jar of starter when all I really need is a tiny bit.

Now, when I am baking frequently, and I'm keeping my starter on the counter, refreshing and growing it regularly, I will have discard. Sometimes, when I’m really busy in the kitchen, I’ll have quite a bit of it.

When I have discard, I look for ways to use it rather than chuck it in the bin.

There are many many recipes that call for sourdough "discard," but my favorite thing to do with discard is to make a simple flatbread.

How to make a simple sourdough flatbread with discard:

For a savory flatbread, stir some salt, garlic powder, and maybe some dried herbs into the discard, OR, drizzle in some honey instead for a sweet and simple treat.

Pour the discard in a lightly greased hot cast iron skillet or onto a hot baking stone in the oven at 500°. Cook for 7+ minutes, until cooked through and lightly browned.

Grate some parmesan over the savory flatbread, or spread the sweet one with cream cheese and jam, or chocolate ganache and fruit, or, as seen here, with my niece’s cherry jam and crumbled feta. So, so good.

3. What is "ripe" starter?

As you're scouring the internet, looking for your next favorite sourdough recipe, you'll likely come across some terms that make you scratch your head and say, "huh?"

Here are a few you may wonder about:

"Ripe Starter"—Ripe starter is a starter that has been fed, has had some time to bubble up and double in size, and is at its peak. Ripe starter is ready to be used in a recipe. Starter usually peaks 6-8 hours after a feeding, depending on the ambient temperature of the room, though starters fed with whole grain or rye will probably ripen more quickly.

"Fed Starter"—This term means the same as "ripe starter." The starter has been fed, has peaked, and is ready for baking.

"Unfed Starter"—This refers to starter that has gone through its 12-24 hour process of feeding, peaking, and deflating. It's ready to be fed again. You can use "unfed starter" in any recipe that calls for "discard," and vice versa.

There is so much to learn about and do with sourdough, but understanding these few concepts will take you a long way. If you keep at it, you'll be baking every recipe you come across—even creating your own—before long.

Still gearing up to bake your first-ever sourdough loaf? You can find some tips for getting started and my favorite basic recipe here.

4. What does is mean to “build leaven”?

Sourdough recipes are written in two different ways.

Some recipes call for a particular amount of sourdough starter, perhaps 1 cup or so. While others ask you to “build leaven.”

The leaven is an intermediary step between the sourdough starter that you keep on your counter (or in your fridge) and the dough you will build to make your bread. “Building a leaven” is used more often in recipes that are more artisanal in nature.

Building a leaven allows to you to keep a small starter. It also allows you to control the starter-to-dough ratio, which gives you more control over the texture and tangy-ness of the bread. A leaven that calls for 30 grams of starter mixed with 85 grams of flour and 85 grams of water will yield a milder final product than a leaven made with equal parts starter, flour, and water. Make sense?

When your recipe calls for “sourdough starter” without the leaven-building step, you can assume you are to use a starter that has been fed 1:1:1 or 1:5:5, however you prefer to keep your starter. Most recipes call for roughly 1 cup/225 grams of ripe starter. If you don’t have that much starter, just build it up with feedings until you have the required amount.

5. What are some good resources for sourdough info and recipes?

I love a good cookbook, especially for guidance with artisanal sourdough techniques and recipes, as well as inspiration from beautiful images. You’ll never go wrong with Sourdough by Sarah Owens, Tartine Bread by Chad Robertson, and The Sourdough School by Vanessa Kimball.

Got other sourdough questions? Or a favorite recipe to share? Drop them in the comments below!