Yeast is one of those pantry staples we never think much about. I never worried about not being able to replenish my yeast until one day I walked into the store to find the yeast section empty. There was no yeast in sight. That’s when I learned about wild yeast.
For the next few weeks, until the store could restock, I baked exclusively with wild yeast. I learned that wild yeast is easy to use in more than just artisan bread. Wild yeast makes a great leavener for pancakes, na’an, biscuits, and all sorts of baked goods.
Here are two methods for capturing the wild yeasts that are everywhere around us all the time.
What Is Yeast?
When I was young, we always had a packet or two of instant yeast in the refrigerator. Now that have a home of my own, I bake more often, and our yeast fills a pint jar in the fridge. Many of us also keep a jar of wild yeast handy.
For many of us, yeast is just an ingredient in bread, wine, or beer. It’s the leavening agent that causes bread to rise and bubbles to form in beer. It’s also a leavening agent in many other baked goods – like croissants and cakes, and in the case of wild yeast, it makes gluten more easily digestible.
Yeast is a living organism. It exists all around us – in every type of natural environment. In fact, each location is home to different varieties of yeast. Yeasts are single-cell organisms that live best in moist, carbohydrate-rich environments.
They feed on the carbohydrates around them – whether flour, pinecones, or even the sugars in the human body. That powdery stuff on the outside of juniper berries? Yeast.
Capturing wild yeast is as simple as providing a welcoming place for wild yeasts to gather.
The wild yeasts that we are trying to capture are those in the Brettanomyces and Saccharomyces genera. Other species of yeast are usually considered harmful to the foods we are trying to create because they cause spoilage.
The reason that we use commercial yeast is convenience and consistency. You always know what flavor you’ll get from commercial yeast. But wild yeast is wonderfully varied, and the flavor might change from one season to the next. That’s part of what makes it so wonderful.
Special Strains of Yeast
A bread instructor once told me that “the only real sourdough is in San Francisco and Alaska.” When I asked him why, he could only say that those two places originally shared a starter. It was the “real” sourdough starter, all others are “fakes.”
If you’ve heard something similar, put it right out of your mind. There are a lot of snobby attitudes about wild yeast, just as there are about pretty much everything.
In truth, wild yeast is wild yeast. Everyone’s sourdough starter or beer is going to be a little different, and every starter will change a bit throughout the year as different yeasts are absorbed from an ever-changing atmosphere.
Every region has its different flavors and the only important factor is whether it works to help you create the foods you want to create and whether you like the flavor.
All wild yeasts have a slightly different flavor, that’s one of the joys of working with wild yeast. Embrace the natural flavors your environment provides and use them to create truly unique baked goods.
In other words, don’t let the purists get you down.
It’s true that some starters are more “sour” than others. They have a stronger flavor because there is a stronger concentration of yeast in the starter. If your starter seems too weak or too strong, it’s just a matter of adjusting your feeding schedule.
Capturing Wild Yeast
So how do you go about collecting wild yeasts? It’s a simple process – just set up a cozy place for your local yeasts to thrive.
To start, get a clear, glass jar or a ceramic canister – something that is not plastic and about a pint or a quart in volume. I usually use a quart-sized jar to give the starter plenty of room for expansion. You’ll also want to grab a small piece of cheesecloth (or other, natural, loosely woven fabric) or a sealable lid.
For sourdough starter, I usually just use an old, cloth, napkin. It allows the tiny yeasts to pass through, into the jar, but it can keep out bugs, dust, and kitchen debris. If you’re using a canning jar, the ring of the lid is helpful in keeping the cloth secure on your jar. Otherwise, a rubber band is necessary.
This is a multi-day process. It takes time for the yeast to colonize. If you’re not used to fermentation, the first few days may seem a little strange, but be patient with your starter.
There are two simple methods that you can use. The first uses flour and water, which is ideal if you want to use your wild yeast to make baked goods. The second uses fruit and water, which is better if you just want to have wild yeast on hand for any purpose.
Whichever method you choose, don’t use city tap water (unless you live somewhere with lightly treated water, such as Portland, Oregon, Witchita, Kansas, or Honolulu, Hawaii).
If your tap water isn’t well water or spring water, don’t use it in your sourdough starter. The chemicals like chlorine and fluoride in tap water will kill the wild yeasts. Buy a jug of spring water or use a water filter to keep the water safe and welcoming.
Flour & Water Starter
Everyone with a sourdough starter will tell you “the right” flour to use. Everyone has a preference. Each flour will react with your wild yeast in a different way. Some people only feed their starter whole wheat, others prefer rye, and others will only use high-gluten bread flour.
I’ve fed my starters with all three types of flour. Ideally, I like to feed regularly with a quality, all-purpose white flour such as King Arthur or Bob’s Red Mill. But, early in the process, I like to give a new sourdough starter a few days of rye flour to support the yeast.
Wild yeasts love rye flour. In fact, if you’ve noticed your sourdough starter is sluggish or if you’ve been neglecting your sourdough, feed it rye for a couple of days to get it back on track.
Whole wheat can give your sourdough a more complex, nuanced flavor. I prefer to add whole grain flours to the levain (the preferment, where I take some of the starter, mix it with more flour and water, and give it a day to ferment before using it to make bread dough.) But many sourdough bakers successfully feed their sourdough starters with whole grain flours.
While you can use whatever flour you have at hand, water is a bit more limited.
Be patient with this process. The starter will go from looking like wet flour, to looking kind of gross, to a full-fledged sourdough starter in a few days to a week and a half, depending on the wild yeasts in your area.
Mix 1 cup flour with 1 cup water. Use a fork or a chopstick to make sure the mixture is gently, but well, blended. Make sure that all the flour is hydrated. It’ll look like thick pancake batter. Then, cover it with the cloth and set it aside.
Keep your starter out of direct sunlight, in a place where you won’t forget to feed it.
Scoop out about half of the flour & water mixture, and dump it in the compost (or start a second starter to keep or give away). Add in a half cup of water, and mix it in. Then, add a half cup of flour and mix that in well. Recover the jar and put it back on the shelf.
Essentially, you’ve taken away some of the wild yeasts that have collected, and you’ve fed the ones that remain.
You’re going to do the same thing today that you did on day two. But today, your starter might look a little different. You may see tiny bubbles in the mix. You might also see a layer of water on top of the starter. All of this is very normal.
Your starter might also smell a little gross. It probably won’t smell like sourdough yet – this early smell is a lot less appealing. That’s normal too. The yeasts are settling in, but they haven’t created a stable community yet. The scent of your starter will improve as it stabilizes.
Days Four through Eight:
Continue feeding as you did the first few days. As you do, you’ll notice more and more bubbling on the surface of your starter. You’ll also notice the watery liquid on top of the starter. As your starter stabilizes, the scent will change to the yeast, beer-like scent of sourdough. Stabilization will also so in the increasing volume of the starter.
After feeding your wild yeasts will be strong enough to leaven the starter. This happens as the yeast feeds and produces carbon dioxide. All of these are signs that your starter is ready to use. But it will continue to need feeding throughout its life.
If you bake every day, you can leave the starter on your counter and feed it every day as you take out some starter to bake with. But, if you bake less often, you can store the starter in the refrigerator and feed it weekly.
Let the starter warm to room temperature before feeding, then give it an hour to work before putting back in the fridge.
Make sure to keep your starter at a sustainable, useable volume for your baking schedule. You don’t need a huge starter if you’re not baking a huge amount each week. In my house, because I bake a lot of small batches, one quart-sized starter is enough for me.
Remember, if you care for your starter well, it can last for years. If it gets sluggish, give it a boost with rye flour and feed it every 12 hours instead of every 24. This will wake it up within a week. But if a starter grows mold, or becomes infested with bugs, it’s ruined. Dump the dead sourdough and start gathering wild yeast again.
Fruit and Water Starter
To start with, you’ll need to get your hands on some organic dried fruit. Don’t use anything that has been treated with sulfur dioxide because the yeast doesn’t like it. Put as much fruit in your jar as you’d like and fill with water to an inch above the fruit.
Seal the jar with a lid and set it in a spot away from direct sunlight and any heat extremes. Gently agitate the water every day but don’t remove or add any water.
After the water starts to bubble, the yeast is ready. This can take up to a week. Strain out the solids and retain the liquid to use instead of liquid or dried commercial yeast.
Once the starter is ready, you’ll need to open the jar at least once a day to prevent pressure from building inside and causing a messy explosion.
You can also use fresh fruit to create a wild yeast starter, but keep in mind two things. The first is that the fruit needs to have a powdery coating on it, which is the yeast. Almost all fruits will have yeast on the skin, so look closely when you’re picking the fruit to select one that has more yeast than others. Never use fruit on the ground.
The second thing to keep in mind is that this type of yeast is usually “sour,” meaning it’s the type that produces lactic acid, such as Lactobacillus and Pediococcus. These types are great for making things like yogurt and bread.
This yeast mix won’t live long unless you are constantly adding new fruit or sugar to the jar. To make things easier, you can put the jar in the refrigerator to extend the life of the yeast. Open and agitate the jar once or twice a day to keep the yeast active and prevent an explosion.
When you’re ready to use the yeast water, add a teaspoon of sugar at least eight hours before you intend to cook or bake.
When it’s time to make some new starter, use half of the existing yeast water in the new batch.
By using some of the old yeast, you’ll speed up the starting process and you could have a new batch ready in as little as one day.