Refreshment of the Starter
As it ferments, sometimes for several days, the volume of the starter is increased by periodic additions of flour and water, called “refreshments”. As long as this starter culture is fed flour and water regularly it will remain active. The ratio of fermented starter to fresh flour and water is critical in the development and maintenance of a starter.
Day to Day Use and Feed
Once your starter has risen and fallen, then it is active. If you plan to use the starter often, leave it covered at room temperature. When your starter is active, you can proceed by feeding it every day (24 hours) or once every 2nd to 3rd day. If you want to use your sourdough it must be fed between 10 – 12 hours before use. Whenever you use some of the starter, it must be fed. You should always have a 500g starter.
Refresh (Feed) your starter by feeding it:
Weight of Starter (250g)Feed it with flour (Starter Weight / 2) and water (Starter Weight /2)
Example250g Starter125g Flour125g Water
Cover and leave to ferment for 24 hours at room temperature. Discard the rest of the remaining starter or give it to a friend.
Refrigerate the Starter to Hibernate:
If you don’t use your starter often, you can keep it covered in a fridge so that the yeast can hibernate.It must be fed between 10 – 12 hours before refrigerating. It can be refrigerated for up to 3 months. To use a refrigerated starter, refresh it by following the guidelines
Day 1 (feed twice in 12-hour intervals):
Starter: 100gFeed: 50g Flour & 50g WaterCover and leave to ferment for 24 hours at room temperature. Discard the rest of the remaining starter.
Day 2 (feed twice in 12-hour intervals):
Starter: 250gFeed: 125g Flour & 125g WaterCover and leave to ferment for 24 hours at room temperature. Discard the rest of the remaining starter.
Day 3:Starter is ready to be used. Follow the day to day use guide to keep it active.
Changing Yeast Recipes to Sourdough Recipes. The amount of flour and water in your starter should always be taken into consideration when calculating your final hydration rate. I always recommend using a 100% hydration starter, because it makes the final formulation of your sourdough easier.100g of sourdough starter is approximately equal to 5 grams of instant/dried yeast. To get an 8 – 10-hour bulk fermentation rate you would need a starter weight that is 20% – 30% of the flour weight. eg: 20% of 500g Flour = 100g StarterWhen you convert, you must also decrease the correct amount of water/liquid and flour from your recipe that you have now added from your sourdough starter. The fermentation time has to be at least tripled compared to the original recipe.
Converting a basic white bread formula from below:
500g strong white bread flour (100%)350g water (70%)10g salt (2%)5g Instant Yeast (1%)
New White Bread Recipe Using Sourdough Starter:
100g Sourdough Starter (50g flour & 50g water)450g Flour (500g flour – 50g flour in starter)300g Water (350g water – 50g water in starter)10g Salt
Calculate Hydration Levels in a Recipe
Now that we know all about hydration levels of sourdough starter, we can calculate hydration levels of the sourdough bread we are making. Here’s a step by step breakdown of how to calculate the hydration level of a specific recipe
Step 1 – Calculate how much flour and water your starter contains and make a note.
Step 2 – Make note of how much flour and water you have in the recipe.
Step 3 – Add up the total amount of flour (i.e. the flour in your recipe, plus the flour in your starter). Do the same with the water. You now have 2 numbers. The total amount of water, and the total amount of flour.
Step 4 – The hydration calculation will be “Total amount of water” divided by “Total amount of flour”, and multiplied by 100. This number is the hydration level of your dough in percentage.
EXAMPLE RECIPE:100g sourdough starter500g strong white bread flour350g water10g salt
Let’s go through the steps for this particular recipe:
Step 1 – My starter is 100% hydration, therefore using 100g would mean 50g is flour and 50g is water.
Step 2 – the recipe contains 500g flour and 350g water.
Step 3 – Total amount of flour is 50g + 500g = 550g AND Total amount of water is 50g + 350g = 400gStep 4 – 400g (total water) divided by 550g (total flour) x 100 = 73% hydration