yeast and God's kingdom

This post is a part of my 2017 Lenten Bread Series. Click here to see the series in its entirety.


The kingdom of heaven is like yeast that a woman took and mixed into a large amount of flour until it worked all through the dough.

The yeasts that ferment, flavor, and leaven a loaf of dough are miraculous little things.

They exist silently and invisibly all around us until we offer them a home and a meal. Then they feast and grow and feast and grow.

Just a small amount of yeast can flavor a whole batch of dough provided the baker is patient enough to give it time to do its work.

But when not tended carefully, the leaven can soon get out of control. Though Jesus compared the kingdom of heaven to a small bit of yeast, a powerful invisible force that has the capacity to transform the world, not all of his references to yeast are positive. He warns against the yeast of the Pharisees and Sadducees, insidious teachings that spread quickly but break down the kingdom rather than building it up.

Sourdough starters contain both yeast and bacteria working together to ferment and flavor the dough. Both good and bad bacteria grow at the same temperature range, and so to ferment any food requires subjecting it to the same conditions that allow bad bacteria to take control.

So how can we know that our sourdough, or our yogurt, or our cheese, or our beer stays safe?

Because bad bacteria cannot survive in the presence of the good.

The best way to protect our starter from bad bacteria is to feed it regularly so that the good bacteria stays in control.

I love the rhythms of the liturgical calendar and the historic practices of spiritual disciplines, patterns of prayer and meditation within the security of strong community. These habits foster the necessary environment for the good yeast and bacteria to thrive. These practices strengthen and feed us to carry on the work of Christ in bringing the kingdom of heaven to earth.


By now your starter should be bubbling and happy. It smells a little bit yeasty but not too sour. It’s alive and almost ready to spread its life to others. But before we can bake our first loaf of bread, we must focus on maintaining a healthy starter.


Every time you feed the starter, it goes through a 24-hour eating process. After its meal, it’s dense and maybe a bit lumpy. Over the next few hours, the water, yeasts, and bacteria will begin unraveling the strands of starch and protein in the wheat, smoothing out the lumps and strengthening the dough. The yeasts will begin feeding on the available starches then burp up carbon dioxide, raising the starter until it is nice and billowy. At this billowy stage, 4-8 hours after feeding, it is perfect for baking.

Once the yeast has finished consuming all of the starches available, the starter will begin to fall. It will shrink back down leaving a little bit of liquid at the top. At this phase, 12-24 hours after feeding, the starter is getting hungry again! It’s ready for the next meal.

You can slow the entire process down by storing the starter in the fridge. The yeast and bacteria get sluggish in cooler temperatures, taking 3-7 days to get through the process. If you plan to bake less than 3 times per week, I recommend storing your starter in the fridge. The night before you want to mix your loaf, pull the starter out of the fridge and feed it. Leave it at room temperature and by the time you wake up it should be ready to mix. Measure out the portion that you need and store the rest in the fridge.

If you need to go longer than a week without baking, just be sure to pull the starter out and feed it 1-2 times per week.


Starter likes to eat four times its weight in flour and water, so 20 grams of starter needs 40 grams of water and 40 grams of flour. If you don’t have a scale, this is about 1 tablespoon of hungry starter, 2 tablespoons of water, and 1/4 cup of all-purpose flour.

You have two options when it comes to feeding your starter. You can weigh how much starter you have in your container and feed it accordingly. If you have 80 grams of starter (1/4 cup), you can go ahead and feed it 160 grams of water (1/2 cup) and 160 grams of flour (1 cup). But unless you are baking regularly, this can get out of hand pretty quickly!

The other option is to feed just a portion of the starter and discard the rest—add it to your favorite muffin or pancake recipe for a nice little tang, feed it to your chickens, or pour it on top of your compost pile. The yeasts definitely love a good compost pile!


Today and tomorrow, we will be feeding just a small portion of our starter. While it hurts to through the bulk of it away, it is necessary to foster a strong, healthy starter.

Measure out 2 tablespoons of starter, 1/4 cup of room temperature water, and 1/2 cup of all-purpose flour. Mix together the starter and water, then add in the flour. Cover and let sit at room temperature.

Watch the starter flow through its eating process over the next 24 hours. As you see it flow through the various phases, meditate on Matthew 13:31-34 and Matthew 16:5-12—two difference parables of yeast.

Pray that God will foster the growth of good bacteria in yourself and in your community, strengthening you to be the hands and feet of Christ in the world, equipping you to fight against injustice and oppression, and using you to bring the Kingdom of Heaven to earth. Pray that as you foster the growth of these good bacteria, you will be keenly aware of the yeasts that threaten to divide the body rather than to build it up.

Repeat the same process tomorrow so that on Wednesday we can mix our first loaf. 

Is your starter happy and healthy? Let me know if you have any questions in the comments below!