General Principles

• Sourdough starter is a LIVING culture which must breathe (don't keep it in an airtight container for long, unless in the fridge) and eat (must be fed).
• Starters may be kept in the fridge (with airtight seal) but should be taken out a day before you want to feed it again.
• Sourdough starter is either active (having been fed recently and having DOUBLED in size) or inactive (not recently fed).
• Active sourdough starter has lots of air bubbles and has DOUBLED in size. It floats in water. Use a (silicone) tablespoon full to check this if you need to be sure.

DO'S

• Keep inactive sourdough starter in an open glass container. Cover this with a moist (not wet) cotton or paper towel. Do not keep in metal container.
• Glass containers help you be able to see and assess the starter.
• Keep sealed air-tightly in fridge if you are not planning to use it in a few days otherwise, feed it regularly. About every 2-4 days.
• Use silicone or wood to handle the sourdough starter.
• Keep at least 120 g (⅓ cup) of starter after each baking project so that you can feed it for future use.

DON'TS

• Don't store in METAL bowls. Metal inhibits the culture growth.
• Don't store in plastic bowls. The acidic starter slowly absorbs plastic.
• Never use bleached flour (won't grow).

HOW MUCH STARTER DO I NEED?

• Some recipes may include instructions on how to feed your starter. In those cases, follow these.
• Some recipes may just list how much active sourdough starter you need. When you calculate how much starter you need to make, be sure to calculate that you have at least 120 g (⅓ cup) of starter left over at the end (for future use).

FEEDING THE STARTER 1:1:1

• There are different ways and ratios to do this. I find the easiest is the 1:1:1 feeding ratio.
• Take the same part inactive starter (in grams) and add in the same part of room temperature water (in grams). Combine with silicone spoon until milky. Add the same part (in grams) flour.

FEEDING THE STARTER 1:1:1 - concrete example

Ingredients

• 120 g inactive starter (= ⅓ cup)
• 120 g room temperature water (= ½ cup), 70℉-85℉
• 120 g unbleached flour (= ¾ cup) (all purpose or whole wheat)

Feeding

• In a tall glass container, combine the starter with the water until milky. Use silicone or wood.
• Fold the flour in and combine until even.
• Make sure there is enough room on top for the starter to double in size.
• With a whiteboard marker mark the height of the starter.
• Cover with a moist (not wet) cotton or paper towel and let rest at room temperature.
• Starter is active when it has doubled in size and you will see bubbles. This will take different amount of times depending on the health and activity level of your starter. If it is a sluggish starter, make sure to feed it a few days in a row and that the temperature of water and room are optimal.

Tip

• Feed starter then spread it out in a thin layer on a parchment paper covered cookie sheet. Let it dry out fully. Break into chips and place in a freezer bag with an oxygen absorber. Freeze for later use. If something happens to your starter you have this backup batch to rehydrate and restart. To rehydrate: place chips in a glass bowl / jar. Thaw. Cover with room temperature water. Soak over night. Mix and give it a feeding.
• I would also keep a sealed jar with backup starter in the fridge. Feed starter. Place in a glass jar and seal shut. No need to leave much space as it won't grow in the fridge. If a black layer of liquid builds up, this can be tossed before the next feeding. When using this fridge starter, give it some time to come to room temperature (1-2 hours) before feeding.