How to Make Wild Yeast Water

• Heat the 500g water to 80-90F to help start the fermentation. Do not overheat.
• Pour the water into a clean jar and add the fruit of choice. Close with a lid*.
• Set the jar of water to ferment preferably at 75°F to 80°F. The oven with the light on can provide a warm temperature, but it must stay below 85F. Higher or lower temperature may prevent fermentation. My oven light heats the oven to 100F or more in about 3 hours which would damage the yeast.
  
• Twice a day, open and close (burp) the jar to oxygenate the water, then shake vigorously over the sink to catch any leakage. Burp the jar again and re-close. After 2-3 days, the water may become a little cloudy and should form bubbles on top that stay for a few minutes after shaking. At first the water will smell like fruit. As it starts to ferment you should notice a sharp kombucha or beer-like scent by the 6th or 7th day. If not, see #6 below.
• The water is ready when the fruit rises to the top and small bubbles are trailing up from the bottom before the jar is shaken. There should also be a release of gases when burping the jar.
  
• IF after 6 or 7 days there is little or no fermentation action, strain the fruit out and return the same water to the jar. Add 30 grams of new dried fruit, 30 grams of granulated sugar or honey, and about 350g of water or enough to fill the jar to the shoulder.
• Continue holding at 75°F-80°F, shaking twice a day until the fruit rises to the top and the water is bubbly. Look for a little sediment of yeast at the bottom of the jar. This should take 2-4 more days after the first fermentation, or this may happen without the second fermentation.
  
• The final test of fermentation is to mix a preferment or levain: To do this, stir together 100g yeast water, 50 grams whole wheat or rye flour, and 50 grams bread flour. I find a chopstick works well for stirring. This mixture will be thick enough to nearly hold the chopstick. straight up.
  
• Let stand covered at 75-80F until at least double in volume and the mixture has a domed top, or it might go all the way to the top of the jar.
  
• Sometimes my cherry water is double or more in 4-6 hours!
  
• The preferment is ideally used as soon as it reaches its doubled peak and is domed on top. However, I've refrigerated preferment for up to 24 hours and it worked fine along with additional yeast water per my recipes.

Maintaining your yeast water

• After baking with the water a couple times and there is about 1-1/2 inches of yeast water in the jar, it's time to re-build the yeast water. Never use it all up or you'll have to start over with the 7+ day process. Follow the steps below to refresh.
• Remove the dried fruit if you haven't already and discard or save for other uses.* Leave the YW in the jar along with any residue/yeast at the bottom of the jar. *The fermented dates keep nearly indefinitely in the refrigerator, so I sometimes mash them into banana bread or muffins. There isn’t much flavor but it adds moisture, fiber, and prevents waste. (Fruit discard recipes to come soon on this blog.)
• Add tap (or spring) water to the shoulder of the jar, which is about 400-500g water (~2 cups), add 30g (2 Tbsp) granulated sugar, 2 dried dates (Medjool) and scant ½ tsp Kosher salt (or ¼ tsp table salt). Salt modulates fermentation which could prevent explosion, and may reduce chance of mold that could occur while the sugary mixture is feeding on the yeast.
• Close the jar with the lid, shake to dissolve and disperse sugar and salt. Burp to release air gases.
• Leave the jar closed at room temperature 2-3 days. This fermentation is less sensitive to temperature so I leave on the kitchen counter which is usually around 62-72°F. Once a day burp to release gases and let fresh air in, then tighten the lid and shake jar to mix well. If a day is skipped it will be ok but the fermentation gases could build up, so for safety it’s best to open and release every day. An active water may look and smell ready in one day, but I usuallygive it 72 hours before using or refrigerating.
• That's it! Your water will wait in the refrigerator for weeks to months ready to use without feeding or discard. Now and then you can open and shake to give it some air.