You can make your own wild yeast starter from scratch. The yeast is already on the grains you use in the starter. You just need to create the right conditions to wake them up! The pineapple juice may sound like a strange ingredient, but it is what makes this recipe work so well. The juice creates an acidic environment that prevents bad bacteria from taking over and causing spoilage during the fermentation period.
05DAY FOUR: Stir mixture and measure out 1/4 cup--discard the rest. To the 1/4 cup, stir in 1/4 cup unbleached AP flour and 1/4 cup water. Let sit 24 hours at room temperature.
06REPEAT Day Four until mixture expands to double its size and smells yeasty. Mixture may start to bubble after a couple of days and then go flat and look totally dead for a couple more days. If this happens, at about Day 6 add the 1/4 teaspoons vinegar with your daily feeding. This will lower the PH and wake up the yeast, which will then start to grow.
07Once the yeast starts growing, starter should be fed equal parts of flour and water in a quantity sufficient to make enough starter for your recipe. Store the starter in the refrigerator when you are not using it. It needs to be fed equal parts flour and water once a week to keep it alive. Either use or discard at least half of it when feeding--THIS IS VERY IMPORTANT to maintian a healthy starter! If you forget to feed it for a few weeks, it probably will be fine but may take several feedings to get it back up to par.