Sourdough starter and Passover

Question

Sourdough starter is a kind of pet. A pet yeast colony, if you want to be scientific about it. Owners give it a name, feed it (daily or weekly, depending on how often they bake bread), make sure it's neither too warm not too cold. The pet can live for years, and some famous colonies have been going for centuries.

Here's the problem: the pet is seriously not kosher-for-Passover.

I'm planning to start my own sourdough starter. But after going through all the trouble, I wouldn't want to kill the pet before Passover. Particularly since the flavours of the starter develop over years.

Is there any way I can keep my starter? Not going to use it, obviously, but can I keep it alive? Can I, for the sake of the argument, define it as a 'pet', rather than 'bread'? Is there some other loophole?

(I live in Israel, so finding a goy pet-sitter isn't really an option.)

Answer 1

The day before you sell, feed your starter. Cover it as you normally would and place that closed container in an opaque, sealed and knotted, plastic bag. Place that bag in a section of your refrigerator out of sight and include that sealed bag in your sale of chametz.

The starter will definitely keep and be healthy for over a week and will not be active in the cold, dark area of your refrigerator.

Answer 2

Following up on the selling idea, you could dry it out (there are instructions online) and put it right next to where you keep your whiskey or whatever you're selling. However, you need to check with whoever you're going to for halacha questions that sourdough starter does indeed fall into the "chesron kis" criterion (חסרון כיס), as that is the halachic basis for selling chametz.