The Care and Feeding of Wild Leaven

By: Ellie Patton

We’re entering the final countdown towards the spring feasts, and many of us are finding ourselves cleaning out cabinets and freezers, searching for any remnants of leaven that may be in our houses that need to be used up before the night of Pesach and the days of Unleavened Bread following. We are commanded to eat only bread made without yeast, and no leaven is to be found in our homes. There are a lot of different trains of thought on what to throw out and what to keep, but it can be incredibly insightful to understand the nature of the leaven the Israelites used, and the intensive, time-consuming process that had to happen every day just to feed and nourish their families.

A few years ago, I started to explore the world of sourdough bread. I got in deeper than I bargained for, which is funny because of how short the ingredients list is. You probably even have everything you need on hand: flour, water, and salt. Typically, the thing that people lack is time, which is the most critical part of making a successful loaf. You see, before you can even make a small loaf of bread, you have to develop your sourdough starter. The starter is what causes the bread to rise- you might know it conventionally as “yeast” or “leaven.” Because our culture has become so strapped for time, you can go to the store and buy little packets of quick-rise yeast to make bread that can be mixed, kneaded, and baked in less than an hour- if you want to even put in that much effort to walk past the perfectly formed loaves in the bakery section of your local Walmart to find yeast. However, the Israelites did not have this commodity. Their yeast was wild, collected from the bacteria in the air, and it had to be tended and fed every day if they wanted results.

To collect yeast from the air, you have to create an environment that is hospitable for it to grow and thrive in. Flour and water will do the trick- but there are multiple factors that contribute to success. You’ll know when you’re successful when your paste begins to bubble and move. You may even see it “burping” as the starter takes in oxygen and releases carbon dioxide, which works its way to the top. If you can’t visibly see activity, it’s not ready and needs time. It will expand by twice its size, sometimes more, then shrink back slightly to a resting, yet active state.


Iron-enriched, bleached, all-purpose flour is extremely difficult to create an active, bubbly starter with. There are next to no nutrients in it- specifically protein. It will take weeks to collect enough wild yeast to make a fluffy loaf. You might even find yourself tending to it like a newborn baby, nursing it all hours of the day (and night). You must have a high-protein, nutrient dense flour for yeast to grow- not like the Wonderbread you grew up on, for sure. Personally, I have had the greatest success milling my own flour from its whole grain form. The Israelites would have only had this option available to them- and their method of milling would have been extremely different than my electric grain mill! 

Quite simply, the flour you buy already milled and bleached has no nutritional value. It’s empty, devoid. You may recall Yeshua referring to himself as the “bread of life.” Though the fluffy white rolls that are ready-made at the grocery store may be tasty- I doubt that’s what he was referring to. I won’t go on about barley, wheat, and other whole grains and the examples their growth cycles set for us in our spiritual walk, but there is something I believe the Father is trying to tell us about the satisfaction and nourishment this ancient food can give us when properly grown and cultivated, undefiled by man’s hand, and properly metabolized. Especially when his feasts are so beautifully designed around their harvest.


In order to host bacteria, you must have warmth and moisture- thus we need water. However, If the water is too cold, your yeast becomes sluggish, stagnant, and there is no growth. If the water is too hot (above 140*) you’ll kill the yeast entirely. There is a sweet, warm spot for optimal growth, activity, and development. 

Not only does the temperature of the water affect your starter, but the source of water can influence the outcome. In my experience, tap water (“enhanced” by man with additives such as chlorine, fluoride, or even contaminated with heavy metals) is not sufficient. Those harmful chemicals are not hospitable for growth. The results I had with tap water were extraordinary- the typical expansion that I saw reduced by half, and the rich brown color quickly turned to grey. When you get used to seeing the beautiful patterns created by the bubbles, you will be able to recognize when something is not right. When using tap water, I found that the arches and “caves” formed by the pockets of carbon dioxide seemed confused, with no rhyme or reason to them. As soon as I switched back to water that had been filtered of chemicals, the pockets began to come back into a recognizable pattern- beautiful in its own way. 


The method of heating your water also influences activity. Many studies show that water is living and has memory- and it is very possible to “kill” water. There are several methods I have experimented with to get room temperature water warmed up to an optimal 110-120* temperature: a kettle on the stove, an electric tea kettle, and a microwave. I won’t go on about radiation and the effects of different frequencies, but adding water that was heated by a microwave (even to the “perfect” temperature) did something crazy to a beautiful and healthy leaven: there was absolutely no activity. The paste seemed to shrink back and pull away from the walls of its container. A breeding ground for healthy activity became a graveyard.

The electric kettle method had better results- there was some activity, but the leaven reached its peak when it expanded to only half of it’s typical size. It stopped, then shrank back. Its expansion happened very rapidly, as did the retraction. It seemed that it followed the pattern of the quickly heated water (the kettle only took about 20 seconds to heat the water to the desired temperature). There was no time to take advantage of the peak point of the leaven, mixing it into a dough to leaven the whole lump. The process happened far too rapidly to enjoy the fruits of my labor.

Slowly heating the water to the desired temperature on the stove gave the best results. It didn’t happen too quickly, and it wasn’t artificially inducted. This starter was healthy, bubbly, and consistent. Its peak activity lasted much longer, and allowed time to take a portion of it to mix into the dough to leaven your bread- if you don’t mix it into your dough at its peak, your bread won’t rise to what it is fully capable of.

Just as Yeshua is the “bread of life,” he also refers to himself as the “living water.” When you think of a pond, a lake, or any body of water that isn’t constantly moving, there’s a great possibility that bad things will start to grow in it. It becomes a stagnant cesspool- and there may be some things in there that aren’t necessarily meant for our consumption. 


Finding a place for your starter to live can be a challenge. Funny enough, it seems that many of the fellow believers I have the pleasure to know have had the experience of moving around quite a bit, just as the Hebrews did in the wilderness. When I am culturing wild yeast, my starter typically moves around my kitchen quite often- resting in different places that are all different temperatures, depending on how much bread I need to make that day (or fruit I need it to bear, if we’re going down that trail). Just as we’ve touched on before, wild yeast needs warm water to thrive. The problem many people encounter is that they will use water warmed to the perfect temperature and see excellent results… for a few hours. They will then place it in an environment that is too cold to foster growth. Bubbles may form, and you see activity and growth- then: nothing. It stalls in the middle of the time it should be “blooming” at its peak. 

Temperature doesn’t just stop with the water. Wild yeast just loves warmth, and another thing it seems to love is darkness. Direct sunlight is a powerful “sterilizing agent.” It has the capability to kill bacteria- but there’s some bacteria that we want in our starter that fights off the bad stuff. Unfortunately, I’ve thrown out more starters than I can count because I left it too long in the sun. The UV rays kill the good bacteria, encouraging mold growth- you might see fuzzy mold, or pinkish-red streaks through the starter.

If your kitchen is anything like mine, doors get left open, the oven is turned on and off, burners stay on for a while, or windows get cracked. Even the amount of people in the kitchen creating body heat influences the temperature- it’s rather impossible to regulate! Thus, my starter never stays in the same place. Some days it could be in a cabinet high out of reach, other days it will be next to the preheated oven just to stay alive. On summer days, it often goes into the refrigerator to stall the activity because I just can’t keep up with the demanding feeding schedule. The beauty of this is that it goes in seasons. I believe that this is part of the Father’s design. 

Just as in our spiritual walk, there are times where we are so hungry and hyperactive that we devour every morsel that we see. In my experience, this hunger must often be tempered and filtered by wisdom and good counsel- we might get so hungry and develop such strong cravings that it’s very possible that some junk food or less-than-optimal influence gets mixed in.  Blessed are they which do hunger and thirst after righteousness: for they shall be filled.” (Matthew 5:6, KJV) It’s imperative that we seek after righteousness and keep our eyes fixed on things above us, and not of this world. This is why who and what we surround ourselves with is so critical. Is what we surround ourselves with creating a warm environment that is hospitable for the growth of love, joy, peace, patience… etc? Or are we so zealous and heated that we’re hosting the leaven that puffs up through negative influence, just as Paul warns in 1 Corinthians 4:18:

Now some are puffed up, as though I would not come to you.  But I will come to you shortly, if  the Lord will, and will know, not the speech of them which are puffed up, but the power.  For the  kingdom of God is not in word, but in power.”

Other times, we may be sluggish and complacent. Our environment just doesn’t have much of anything in it that excites or motivates us to bear good fruit- our love grows cold. While there may be times where it seems as if the Holy Spirit is just pouring out on us without much effort at all, there can also be dry spells where we must diligently seek him out every day, whether or not the results we desire are visible.

“ I know your deeds, that you are neither cold nor hot. I wish you were either one or the other! So, because you are lukewarm—neither hot nor cold—I am about to spit you out of my mouth.” –Revelation 3:15-16

I truly do not wish to be spit out of Yah’s mouth. Regulating the temperature of our spiritual walk has a lot, if not everything to do with us.

“And ye shall seek me, and find me, when ye shall search for me with all your heart.” -Jeremiah 29:13 


It takes a bit of time to collect enough yeast to leaven a whole loaf. Typically, it will be about a week from when you first mix your starter before you can use it to successfully bake bread. Depending on how “yeasty” your environment is, it could be sooner than that, or later. However, you can’t just mix your flour and water and leave it be for a week. It has to be fed, or else, just like us, it will starve. Every day, a portion of it must be removed, till just about a tablespoon is remaining, then new flour and water must be mixed in. This remaining portion of yeast basically “eats” the new portion, until all that remains is wild yeast. If you let your starter sit without feeding it, it quite literally will starve. The first signs are decreased activity and bubbling, but it might also begin to produce a new substance called “hooch.” As you might have guessed, sourdough is a fermenting process. Hooch is alcohol- and it’s basically the byproducts of the fermenting/digesting process of hungry yeast. It’s harmless enough- but it is a signal that it needs to be fed. If you leave it for much longer without feeding it, the “metabolism” of your starter will tank, and it will die. It’s something that must be kept up with daily. I have known some enthusiasts to feed their yeast every 3-4 hours, tending to it like a newborn baby.

When you feed it, if you continue to just add more flour and water into your growing culture, you’ll end up with a situation that could be compared to breeding rabbits. You will quite literally be knee-deep in sticky leaven. The problem is that quantity is not equal to quality. In 1 Corinthians 5:6, Paul is well acquainted with the leavening process:

“Do you not know that a little leaven leavens the whole lump?” 

It really only takes a tiny bit. In my experience, when I have decided that I wanted an extra fluffy loaf and consequently added more sourdough starter, the fermenting process simply gobbles up your bread dough, and you’re left with a sticky, gooey mess that won’t hold up or have any shape. It’s weak and is forced to conform to the shape of the vessel it’s baked in, often clinging to the bottom and sides in a burnt mess, rather than holding the shape that the ‘maker’ intended it to be in. This is one of my favorite parts of the breadmaking process because of how obvious the symbolism becomes once you experience it firsthand! This is just one reason it is so important to watch carefully where our influence is coming from, lest we conform. Thankfully, this is the season to be transformed, making room for the good, acceptable, and perfect. 

“And be not conformed to this world: but be ye transformed by the renewing of your mind, that ye may prove what is that good, and acceptable, and perfect, will of God.” -Romans 12:2 

Other environmental factors

Like I said, my starter often moves around my kitchen. Sometimes, it’s not me who moves it- often it will be placed elsewhere to make room for other things. My favorite spot to put it is in a corner cabinet, right next to my oven. It’s dark, warm, and out of the way where it will get knocked around and disturbed. However, that cabinet is the home to many other dry goods. Once, my starter got put on the very top shelf, the place where we typically keep things we don’t use very often. When I pulled it out to feed it and make a loaf of sourdough, it had an odd smell to it. I didn’t think too much of it- it looked healthy enough and it seemed like it was doing its job. When I pulled the bread I had made out of the oven and we cut into it later that day, there was a peculiar taste to it that I had never experienced before. It wasn’t bad, just different. I realized that my starter had been put on the shelf that also housed molasses and sorghum. Somehow, as it was feeding off of the wild yeast, it took on the flavor of these two sticky syrups. This led me to conduct an experiment with a couple more loaves of bread. I moved the starter to the next shelf down. I was anxious to see if it would happen again and what it would taste like next, since there are a variety of things stored there. Surprisingly, the loaf tasted like peanut butter! Again, not bad- just unusual. The last shelf I stored it on contained a variety of vinegars: balsamic, white and red wine, rice, apple cider, etc. However, I didn’t get the result I really wanted. Though some people will actually add vinegar to their sourdough starter to enhance that signature “tang,” the variety and abundance of vinegar seemed to confuse the starter. Yes, it was a sour dough- but the acid influenced the flavor so much that it was just… funky. Not very enjoyable. 

I’ve gotten the question before- “why didn’t you just put a lid on your starter so those things don’t affect the taste?”

Well, here’s the thing: yeast is living. It requires oxygen to thrive, and it actually produces carbon dioxide, just like we do as we breathe. When you have an especially active starter, a tightly sealed lid doesn’t allow the carbon dioxide to escape, creating pressure that forces the starter through any crevice it can find. You may wake up to find a gooey mess in your cabinet, an exploded gasket, and sourdough starter everywhere. And I mean, everywhere. A thin piece of cheesecloth does the trick to keep it clean and covered- but the taste is still affected when the yeast feeds off of the other, smaller particles in the air. You pick your battles.

Do we shelter it and shield it from every impure influence that surrounds it, so that we have a perfectly pure starter, undefiled from the unwanted flavors of vinegar or peanut butter? A drastic and possibly outlandish analogy, but thankfully, we have a little more choice into what we “digest,” unlike wild yeast. If we isolate to keep ourselves from the world, we also lose our capability to minister to it, and spread Yah’s truth and light. He also very helpfully gives us just a couple of guidelines for some things to stay away from, as well as some areas we are to proceed with caution in. 

As we enter the feast of Unleavened Bread, my observations are that leaven and yeast are not necessarily bad things. There is a key word that I hope has stuck out that I believe can give perspective on leaven: “influence.” Good or bad, it can be impacted by a variety of factors, and  there are some incredible lessons we can learn from watching its life cycle. We even countdown 50 days from Firstfruits to Shavuot, culturing a new starter that will leaven 2 giant loaves to be presented on Shavuot- yeasty, fluffy, and risen bread (But that’s another topic)! However, I believe that the Father, in his perfect design, wishes us to reevaluate and examine our hearts each year and start fresh. Are we becoming puffed up with false doctrine and getting stuck in our old ways and traditions? What do we need to throw out that is doing us more harm than good? What is the nature of the leaven that we are using to nourish our families and stimulate activity? Do we nourish it, feed it with the proper ingredients, and stay vigilant about what goes into it so that its growth is visibly active and healthy? There are so many analogies, parables, and questions that we could glean from leaven alone. I think that Yeshua summarizes this beautifully in Matthew 13:

He told them still another parable: “The kingdom of heaven is like yeast that a woman took and mixed into about sixty pounds of flour until it worked all through the dough.”

Jesus spoke all these things to the crowd in parables; he did not say anything to them without using a parable. So was fulfilled what was spoken through the prophet:

“I will open my mouth in parables, I will utter things hidden since the creation of the world.” Matthew 13:33-35

I hope that this has blessed you.

Ellie Patton

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