For many years I thought I understood what lived inside my starter.

Like most bakers, I knew about lactic acid bacteria, often called LAB. They are the organisms responsible for the pleasant sourness in sourdough bread. Bakers talk about them often. Recipes and articles frequently mention the acids they produce and how those acids give sourdough its flavor.

But strangely, people rarely talk about the other major player in the jar.

The yeast.

After all, when we bake with sourdough, we are baking with wild yeast — yeast captured from nature rather than commercial yeast produced in factories. That wild yeast is what makes the bread rise.

Yet in most discussions about sourdough, the yeast itself is almost an afterthought.

Looking back now, I realize that I spent years paying attention mostly to the bacteria and almost none to the yeast.

And I thought that was normal.

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When I first built my own starter many years ago, I remember seeing something that frightened me. One day the starter collapsed into a runny mixture filled with tiny pinhole bubbles. It looked broken, almost spoiled.

At the time I assumed I had destroyed it.

That experience is actually what led me to order a mature starter from Breadtopia, which is how Daisy first came into my life.

Over the years I noticed that same runny state appear occasionally if I forgot to feed Daisy and she sat too long on my warm kitchen counter. Especially in a kitchen that often lives between 76°F and 85°F (24–29°C), things can change quickly.

When that happened, I simply fed her fresh flour several times and she seemed to recover. She would rise again, smell healthy, and produce good bread.

So I assumed the problem had been solved.

Only much later did I learn that removing excess acidity from a starter is not nearly as simple as it appears.

A starter can look healthy again long before the internal balance is truly restored.

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For seven years Daisy looked remarkably consistent.

She rose easily — often two and a half to three times her original height. She smelled pleasant. She produced bread that was often very good.

So I never questioned her health.

If something went wrong with a loaf, I assumed the problem must be my technique.

Perhaps my fermentation timing was wrong.

Perhaps my shaping was too aggressive.

Perhaps I had misjudged the dough.

So I worked harder on the craft of baking.

What I never suspected was that the problem might be inside Daisy herself.

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The first real clue arrived when Daisy became Daisy Madre.

Seeing that transformation made something immediately obvious.

Something scientific had changed.

The starter I had known for years had always looked roughly the same: a textured surface, a gentle dome, and bubbles trapped beneath the top layer. It rose beautifully, but the surface itself rarely broke open.

When Daisy Madre appeared, everything about that surface changed.

The texture became smooth and creamy.

The dome disappeared.

Large bubbles rose all the way to the surface and pushed through the top membrane like tiny volcanoes.

And the gluten webbing inside the starter became astonishingly strong.

The difference was so dramatic that I immediately knew something deeper was happening.

I didn’t yet know what.

But I knew there was a biological explanation.

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Later, as I began investigating what had happened, I started to understand that a sourdough starter is governed by three invisible forces.

Yeast.

Lactic acid bacteria.

And enzymes.

These three forces interact constantly inside the jar, shaping the behavior of the culture in ways we cannot see directly.

Yeast produce gas and drive fermentation.

Lactic acid bacteria produce acids that flavor the bread and control microbial balance.

And enzymes — particularly proteases — slowly break down proteins inside the flour.

Those enzymes are responsible for a process called proteolysis, which weakens the gluten network over time.

For years I had been seeing the signs of this without fully understanding them.

When Daisy sat too long in my warm kitchen, I noticed that the starter would become weaker and more fluid. If I tipped the jar, the starter would pour out more easily.

That never happened when Daisy had been kept cooler.

At the time I didn’t know the name for this process.

But I could feel that something was happening to the gluten structure.

Now I know that what I was seeing was the effect of enzymes working alongside the acids produced by bacteria.

Together they slowly weaken the gluten network if conditions allow them to act too aggressively.

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Looking back over seven years with Daisy, I can now see many signs that the starter was likely LAB-dominant much of the time.

The bubbles often formed underneath the surface rather than breaking through it.

The top of the starter had a slightly rough texture — almost like linen fabric — rather than the creamy smooth surface that Daisy Madre later displayed.