Sourdough Resources

Rehydrating Sourdough Starter from Dried Flakes

Materials & Ingredients Required

8-16 oz glass or plastic jar (or other small, clear kitchen vessel, for housing your starter), along with a loosely fitting cover for the vessel
Digital kitchen scale
Kitchen table spoon or butter knife, for stirring
Wheat flour (any kind, such as whole wheat, all-purpose, or bread flour. Avoid enriched or bleached flours. Local and organic is recommended, whenever possible)
Room temp water (tap or filtered are fine)

Day 1:

Measure the mass (in grams) of your empty 8-16 oz container you have chosen, and write it down (sharpie on masking tape works well, and you can stick it right onto the vessel).
Tare (or zero) your container on a digital scale so it reads 0 (zero) g.
Add:

20g of your dehydrated starter (save the rest!)
40g of flour
40g of water (room temperature, or slightly warm)
(if you can, measure the temperature of the water so it is between 70-85 degrees.)

You should now have 100g of starter, flour and water total in your container.

Remove the container from your scale and mix well, either with your hands, or a tool (spoons, knives, spatulas all work well). Make sure you hydrate all of the flour with the water, leaving no dry spots (clear containers will help).
Allow to sit loosely covered for 12 hours in a warm spot.

After 12 hours, stir your starter. Then allow it to sit for another 12 hours.

Day 2:

The feeding process BEGINS! This is a very similar set of steps as Day 1, and will be repeated daily for the next 3-5 days:

Place your container with the previous day’s mixture onto the scale and tare it.
Discard 80g of the mixture, so you are left with 20g in the container. The 80g amount that is discarded is referred to as sourdough discard (or just discard) and you may choose to save it for use in certain recipes - more on this in the FAQ below!
Tare your container (with the 20g remaining) again until the scale reads zero, and add:

40g of flour
40g of water

Mix well, cover, and leave it again for 24 hours, giving it a good stir after 12 hours.

Day 3:

Repeat Day 2’s steps for about 5-7 days, until you start to see regular bubbling and rising activity in the container. Congrats, you are now on your way to having an established starter!

Frequently Asked Questions

How long can I keep my dehydrated starter before using it?

In theory, a dehydrated starter will last indefinitely when stored in a cool, dry space within an airtight container. Dried yeasts have been recovered from archeological sites and successfully rehydrated, and even used to bake bread...pretty cool stuff!

What ratios of starter, flour, and water should I follow to feed my starter?

A healthy starter (kept at 100% hydration) is fed in at least equal parts:

1 part flour - 1 part water - 1 part starter (in grams)

For example, 10g of starter should be fed with at least 10g flour and 10g water. It is common for home bakers to keep a small amount of starter on hand, and scale up as needed. If you are scaling up for a larger batch, you can certainly feed 10g of starter with 30g flour and 30g water, or at even higher ratios. It will take more time for the starter to work through this much food, and you can use this to your advantage in your feeding schedule.

Beyond this golden ratio, there is a whole world of starters that may be maintained at different ratios for different purposes. If you are interested in learning more, keep an eye out for an advanced sourdough class in the future that explores this multitude!

What about the "discard?"

When you need to feed your starter but are not going to bake with it, you must still remove some of the spent (or active) starter from the container - this is called discard. You can continue to add discard to the same container (as long as there is space) until you are ready to use it in other recipes. Or, you may add it into your compost pile. Discard should be kept refrigerated, and not be kept longer than one month in the fridge.

Why do we remove discard with every feeding?

If you keep to a consistent feeding schedule, but are not removing some starter to bake with every day, you are going to end up with an exponential amount of starter.

50g starter + 50g flour + 50g water = 150g new starter That means the next feeding will, at a minimum, have to include 150g flour and 150g water...then 450g...but by removing some starter every time and keeping the mother culture small, it requires less flour and water at each feeding, which will produce less starter for you to have to manage.

What is a 100% hydration sourdough starter?

A starter that is maintained with equal parts of flour and water is considered a 100% hydration starter, in reference to "baker's math," which calculates percentages in recipes based on the full amount of flour. For example, through baker's math, a starter that has 100g of flour and 100g of water has a 100% hydration level (hydration level = flour/water). A starter that has 100g of flour and only 75g of water would be at 75% hydration.

A one-to-one ratio of water and flour is the most common form of starter used in home sourdough baking in this part of the world. Most sourdough bread recipes you will find call for a 100% hydration starter. If a recipe does not specify at all (for example, just stating "sourdough starter") it is safe to assume that the recipe likely calls for a 100% hydration starter.