A layer of liquid shows up on top of your culture. Here's what it actually is.

Hooch is mostly water - but water carrying the byproducts of fermentation: acid, alcohol, esters.* It's a natural byproduct of fermentation. It's not mold. It's not spoilage. It's not a sign your culture died. It's waste products and pollutants - toxic for your culture, but also doing something useful: it acts as a protective barrier, isolating your culture from foreign bacteria that could be bad for it.

Why It Develops

Fermentation needs food. Flour feeds the yeast and bacteria in your culture - water is what activates that process and flushes out the byproducts. Given enough time, the culture separates. Through time and neglect, the byproducts float up to the top as a thin liquid layer - grayish, brownish, sometimes almost clear.

This is exactly why the popular feeding requirement exists - feed the jar every day, and you never give the culture enough time to separate or to produce excessive waste byproducts.

Why It isn't a Problem with the Mother Dough Method

I don't feed my culture. I've never discarded. I use the mother dough method - no jar sitting on the counter, no daily feeding schedule to maintain. So the anxiety around hooch, the thing that drives so much of that feeding necessity, doesn't apply to how I maintain my culture.

That said, the biology doesn't change. If you set aside a piece of mother dough and let it sit too long without using it - especially for an extended stretch - it can develop that same liquid layer.

What To Do About It

Your best choice depends on what is most important.

• Stir the hooch back in - best for keeping the viscosity consistent.

• Do nothing - best for keeping things simple. As an added benefit, as the toxins increase, the culture slows, is inhibited, and goes dormant (although this won't guarantee you'll be able to reactivate your culture).

• Pour it off and replace it with a little clean water - the better option for a thriving, active culture, since it purifies your culture's environment.

Either way, how much this affects the culture underneath depends on the amount of culture, the microbial strength, and how much hooch built up.

To get it back to a usable condition, pour off the hooch, refresh its water, and feed flour. Repeat if necessary.

Until next time, let's give thanks for our daily bread…

John Durrant

Breaducation | The Sourdough Academy

*Also present in trace amounts: hexanal, nonanoic acid, acetoin.