To begin, mix the whole wheat flour & spring water together in a glass container, until the flour is incorporated. It will look like a thick paste. Set the bowl, loosely covered, on the counter at room temperature (about 70F), for 24 hours.
If you have a drafty house your starter may need a little help staying at temperature. A heating pad or electric blanket (set to medium) is a great little cheat. Just place the starter bowl on top and let it nestle in. I have also done this using my oven with an iron oven ‘stone’. Just warm your oven to about 80F, and place the starter on a rack after you’ve switched the oven off. Keep an eye on the temperature using an oven thermometer - try to keep it consistently between 70-80 degrees.
After 24 hours, you may see some slight bubbling - or nothing at all (don’t worry, the bacteria and yeasts are in there!). Scoop out half the starter and throw it away. Add 1 cup of AP unbleached flour, and ½ cup of room temperature spring water to the bowl. Stir thoroughly and cover, place back on the counter/heating pad/whatever you’ve been using.
48 hours later, you’ll probably start to see some changes to the goop. The starter will have a slightly fruity aroma (like young wine), and there will be some bubbling and expansion. You’re now going to start feeding the young starter twicea day, 12 hours apart.
Scoop out half of the starter (about 4 ounces), and discard. Add 1 cup of AP unbleached flour and ½ cup room temperature spring water. Stir well, cover, and let sit in a warm spot. 12 hours later, repeat the procedure.
This is the point when variations in temperature or humidity can affect your starter growth. Just keep scooping/feeding/stirring/warming your starter - don’t give up if it looks more like a flour paste you might have eaten at craft time in kindergarden rather than beautiful natural leavening. My own batch took TWO WEEKS to get going, but it’s worth it. Trust me. As you wait for your newborn baby starter to find it’s legs, think of names for the flour paste, it helps. We named ours “Paul Riser”.
Day 5, 6, 7, etc., keep feeding and watching. Once you get rivulets & foamy bubbles, you’re almost there! If your starter suddenly bursts to life and blubs out of the container, you’ve hit the jackpot - The starter will smell sweet and a little acidic.
Discard all but 4 ounces of starter and give it one last feed / rest. You’ve now got a strong starter that can be stored in the fridge, and at this point you can change to feeding it 1 time per week.
When you want to use it for a recipe, scoop 4 ounces of starter into a plastic container with a lid, feed ½ cup AP flour and ¼ cup water, and let rest for about 3-4 hours, until foamy.
At the same time, the main starter (or “Mother”), should also be fed 1 cup AP flour and ½ cup spring water and let to rest until foamy. Then, you can store in the fridge once again.