You will need: 2¼ ounces rye flour + 2¼ ounces waterUsing a wooden spoon, mix the rye flour and water in a mason jar or non-reactive bowl. Cover loosely and place in a dark place at 70°F for 24 hours. (I put mine up against the counter right next to my stove.)Your unfermented Starter will be the consistency of thick cook dough. It will loosen up over time.
Day 2
You will need: 2¼ ounces rye flour + 2¼ ounces waterAdd the rye flour and water to the starter. Mix with a clean wooden spoon for 30 seconds until the flour has been incorporated. Cover loosely and place in a dark place at 70°F for 24 hours.
Day 3
You will need: 1⅛ ounces rye flour + 1⅛ ounces waterAdd the rye flour and water to the starter. Mix with a clean wooden spoon for 30 seconds until the flour has been incorporated. Cover loosely and place in a dark place at 70°F for 24 hours.
Day 4
You will need: 1⅛ ounces rye flour + 1⅛ ounces waterIf bubbles have started to form and the flour has begun to ferment, discard ⅔ of the mixture in the jar. Add the flour and water to the remaining ⅓ and mix for 30 seconds until the flour is well incorporated. (If the mixture has not started to ferment repeat step 3.)
Day 5
The starter should be mature by this point and is ready to use. Use the starter as needed. After use, see feeding instructions.
If you want to convert your starter to a white flour or whole wheat Starter, you may begin feeding it with all-purpose flour from this point on.
Feeding Sourdough Starter
The amount you feed your sourdough starter depends on how much of it you have to start with. You want to approximately double your starter each time you feed it. For example, if you have 8 ounces of Starter, you will feed it 4 ounces of water and 4 ounces of flour.
If you have more starter on hand than you anticipate using for baking, you can toss (or share!) a cup or more of Starter and then double what remains. You always want to have at least 8 ounces of Starter leftover after baking to keep the process going.
Healthy Starter can be refrigerated for up to a week between feedings; however, most sourdough experts recommend feeding Sourdough Starter at least twice a week for best results. (Honestly, I often leave it FAR longer with no problems.)
Read Sourdough Starter: Care & Feeding for tips and advice for the care and feeding of a sourdough starter, including how to maintain it, and how to revive a neglected starter.
Notes
Never allow reactive metal to come in contact with your sourdough starter. Always use a wooden spoon to stir when you feed it. Starter should be stored in glass, plastic, or pottery containers. Always leave enough room in your Sourdough Jar for the Starter to triple in size. It usually only doubles, but you want to leave some wiggle room.Never cover your starter with an airtight lid.