100 Grams Sourdough Starter to Cups: Starter Conversion Chart

Sourdough starter is a live mix of flour, water, wild yeast and bacteria. When it is fed and active, it fills with gas bubbles, so a cup holds less weight. The King Arthur Baking sourdough guide notes that starter volume changes with its thickness and with how well it is stirred down.

Ripe Starter and Unfed Starter

King Arthur calls starter ripe when it has been fed and has risen until bubbly and doubled. Discard is the unripe starter left over after a regular feeding. Ripe starter is lighter per cup, while stirred down discard sits at the heavier end of the range.

Starter Hydration

Many home starters, including King Arthur’s, are fed equal weights of flour and water, which bakers call 100 percent hydration. That means 100 grams of starter holds about 50 grams of flour and 50 grams of water. A stiffer starter uses less water, so its flour and water split is different.

This chart turns gram amounts from bread recipes into cups. The first cups column is for ripe starter, and the second is for unfed starter. The last column gives the closest cups and spoons for ripe starter.

How Much Is 100 Grams of Sourdough Starter in Cups

How much is 100 grams of sourdough starter in cups? It is 0.44 cup of ripe starter, which you can measure as 1/4 cup plus 3 tablespoons. For unfed starter, 100 grams is about 0.41 cup. Either way, it is a little less than 1/2 cup.

150g Sourdough Starter to Cups

150g sourdough starter to cups is 0.66 cup, which is about 2/3 cup of ripe starter. For unfed starter, 150 grams is 0.62 cup, a bit under 2/3 cup. If the recipe gives grams, a scale is the most exact way to measure it.

50 Grams and 200 Grams of Starter in Cups

50 grams of starter is a scant 1/4 cup, the amount King Arthur keeps at each feeding. 200 grams is 0.88 cup, or 3/4 cup plus 2 tablespoons. 227 grams is exactly 1 cup of ripe starter.

Older recipes often list starter in cups. Multiply the cups by 227 for ripe starter, or by 241 for unfed starter. This chart does the math for you.

1/2 Cup and 1/4 Cup of Starter in Grams

Half a cup of ripe starter weighs about 114 grams. A quarter cup weighs about 57 grams. King Arthur lists 3 tablespoons of ripe starter at 44 grams, which matches this chart within 1 gram.

King Arthur Baking feeds its starter with equal weights of starter, flour and water, a 1:1:1 ratio. The King Arthur starter recipe keeps 50 grams of starter, then adds 50 grams of flour and 50 grams of water. That gives 150 grams of fresh starter, about 2/3 cup before it starts to rise.

When Starter Is Ready to Use

King Arthur says a healthy starter should at least double in about 6 to 8 hours after feeding. It should have lots of bubbles and a tangy smell. Use it near its peak for the best rise.

You only need one number for each kind of starter. Use 227 grams per cup for ripe starter and 241 grams per cup for unfed discard. Divide grams by that number to get cups, or multiply cups by it to get grams.

Grams to Cups

For 120 grams of ripe starter, 120 ÷ 227 = 0.53 cup, or about 1/2 cup. For 300 grams, 300 ÷ 227 = 1.32 cups, or about 1 1/3 cups. For unfed starter, divide by 241 instead.

Cups to Grams

For 3/4 cup of ripe starter, 0.75 × 227 = 170 grams. For 1/3 cup of unfed starter, 0.33 × 241 = 80 grams. For 1 1/2 cups of ripe starter, 1.5 × 227 = 341 grams.

Tips for Measuring Starter

Starter is sticky and full of air, so cups are less exact than a scale. King Arthur calls a digital scale one of the most important sourdough tools. These habits help when you must use cups.

• Weigh when you can. Set the bowl on a scale and spoon starter straight in.
• Stir before measuring. Stirring knocks out air, so the cup holds a steadier weight.
• Note ripe or unfed. Ripe starter is lighter per cup than discard.
• Wet the cup first. A damp cup helps sticky starter slide out.
• Keep the ratio by weight. Feed with equal grams of flour and water, not equal cups.