On day 1, stir together 3 tablespoons whole wheat flour and ¼ cup pineapple juice in a sterilized glass jar until it forms a thick paste. Cover with a towel, or with plastic wrap with small holes poked into the top, and let stand at room temperature for 48 hours. Stir this mixture every 12 hours.

On day 3, add 3 tablespoons bread flour and ¼ cup unsweetened pineapple juice to the jar and mix well to combine with the previous mixture. Cover and let stand at room temperature for 48 hours. You will start to see some signs of fermentation by day 4 – small bubbles forming in the mixture and on the top and a pleasant yeasty smell. If you do not see any activity or if the mixture smells foul or sweet, you will need to throw the mixture out and start again at day 1.

On day 5, add to the mixture ⅓ cup bread flour and ¼ cup purified or spring water, at room temperature, and stir well. Cover and let stand for 24 hours. You should see the starter expand in the jar. A good way to track this is to use a rubber band – place it at the level of the freshly fed starter. You should see it rise over the rubber band as the starter becomes more active before it falls back to its starting height.

On day 6 (and for days beyond that), discard all but ½ cup of starter. Add ½ cup bread flour and ⅓ cup purified or filtered water, at room temperature, and stir vigorously. Repeat this process every 12-24 hours depending on how hungry your starter is.