Step 1: Find your container

Start by finding a jar or bottle that will hold at least 32 ounces, preferably more like 34 ounces (though 32 ounces will do in a pinch). I used a wide-mouth Ball jar that holds 8 cups.

Use a funnel to put water, granulated sugar, and dried fruit into the jar.

Step 2: Shake to dissolve sugar

Screw the cap on the jar and shake vigorously to dissolve the sugar. Loosen the cap a half-turn and put the bottle somewhere warm; 78.8°F is optimal.

Step 3: Shake the bottle

For the next 4 days, shake the bottle twice a day. Unscrew the cap to let out any pressure buildup, screw it back on, then shake it well.

After 24 hours you should see bubbles.

By the end of 4 days, the water should be frothy on top, and you should be able to smell the fruit fermenting: think a combination of orchard and barroom.

Step 4: Feed the yeast water

On day 5, add the following to the bottle:

• 2 dried figs or 1 dried date
• 5g (1 teaspoon) salt
• 20g (1 1/2 tablespoons) granulated sugar
• 400g (1 3/4 cups) water

This is where you might have trouble with a 32-ounce bottle. Adding 400g of water takes you up to about 31 3/4 ounces plus the space the dates take up. To leave a little head space at the top for bubbles and shaking, you’ll probably have to reduce the water a bit.

Shake the bottle vigorously to dissolve the sugar. Put it back in its warm spot, and shake twice a day, uncapping and recapping each time, for 4 more days.

After 8 days, you’re ready to build your final starter and make bread. Depending on the temperature in your kitchen, it may take less time. Mine was ready in five days, but I kept shaking it for a couple more days to be sure.

Step 5: Build the Starter

Build a starter by combining yeast water and flour in equal parts (by weight). I used the method from Piotr Lesnianski (one of the admins for the Fermenting and Baking with Wild Yeast and Waters FB Group)

In a separate, clean, and sterilized jar (a quart-size canning jar works well), take 75-100 grams of fig yeast water and mix it with 75-100 grams of whole wheat flour. I used red fife flour. Put a lid on the jar and let it rest at room temperature for 6-8 hours. Feed it again with a 50/50 mixture of whole wheat flour and water and let it rest for another 6-8 hours.

During this time, you should start to see fermentation. It will grow in volume and you should see lots of air bubbles. Piotr feeds his sourdough a 3rd time with a 50/50 mix of 150 grams of flour/water. My starter was ready to go after the 2^nd feeding.

Step 6: Make your favorite bread

Use the starter you built in step 5 to make your favorite sourdough bread.

Step 7: Maintaining the yeast water

Each bottle will make several loaves of bread, but, if you want to continue baking with this method, you will need to keep it going. Make sure to save 200 g of yeast water.

Combine the 200 g with 700 g of tap water (might be less because of the volume of the bottle), 35 g of sugar, 3.5 g of salt, and 2 dried dates.

Shake twice a day for 2 to 3 days, until the yeast water is foaming nicely. Strain out the dried fruit, and store water in the refrigerator.