Sourdough starters can live for generations. Are some in the Puratos library 500 years old? There’s no way to prove it . . . but maybe.

Say your great-grandmother passed a bit of her sourdough starter on to her kids. Her kids fed it and passed a portion on to their kids. Eventually, a bit of it became yours. And guess what? Some of your great-grandma’s “bugs”—the bacteria that lived on her hands—might still hide inside it.

Cells make up the human body. But parts of you aren’t . . . you. You have just as many bacteria in your body as you have cells. Some bacteria types look like rods. Some look like spirals or spheres. Because of bacteria’s work, your body can absorb nutrients. Yeast and bacteria move through dough and make it rise. And while that happens, people’s bacteria and bacteria from the air move through too.

You might say we’re a bacteria zoo! And so was your great-grandma. Wouldn’t it be fun to pass down a you-nique sourdough starter to your own kids?

Start! Make your starter. Get help to sterilize a large glass bowl or jar by pouring boiling water over it. You’re becoming a bacteria farmer—but you don’t want to grow the baddies! If you let them in at the beginning, those bacteria will make your dough stink and grow mold. Follow these steps. In about a week, you'll have enough starter to share.

Day 1: All flour holds wild yeast. You just have to get it going. Mix ¾ cup plus two tablespoons of flour with ½ cup of pure water. Do this in a glass (not metal) container. Right now, your starter looks like a glob of paste. Let it sit somewhere with a temperature between 70 and 75 degrees—maybe the top of the fridge. Wait 24 hours.

Day 2: Check. See bubbles? If yes, that’s good. Wild yeast is at work eating the sugars in the flour. (No, you didn’t add any sugar. But all flour breaks down into sugar molecules.) The yeast lets out carbon dioxide and alcohol. The starter becomes more acidic, warning away harmful bacteria. No bubbles? No worries. Your starter just needs more time.

Feed your starter. Again, use ¾ cup plus 2 tablespoons of flour and ½ cup of water. And while you’re feeding your pet, go ahead and give it a name. I call mine Charlotte Brontë.

Day 3: Feed your starter again. It’s getting bigger. Stir with a spoon. Bubbles should pop, pop, pop!

Day 4: Feed again. Does your starter smell vinegary? Good! That’s why they call it sourdough.

Day 5: It’s go time! Well, probably. If your starter looks loose and bubble-covered and has doubled in size, you’re ready to use it in a recipe for sourdough waffles, buns, or bread. If not, keep feeding it for a few more days.

For the next 500 years . . . After using, get rid of half your starter. Feed the remainder again, cover tightly, and stick it in the fridge. Now you have to feed it less often than you feed your dog—just once a week.

He told them another parable. “The kingdom of heaven is like leaven that a woman took and hid in three measures of flour, till it was all leavened.” — Matthew 13:33