Kensington Market Sourdough Starter (Hydration Guide)
A sourdough starter is at 100% hydration when it contains equal weights of flour and water. The name “Kensington Market” does not specify a unique hydration or feeding method, so weigh the starter and its ingredients rather than relying on a name or cup measures. This guide shows how to calculate, feed, ferment, store, and use a consistent 100%-hydration starter.
If you are trying to match a starter from a baker or recipe in Kensington Market, the key detail to ask for is its flour-to-water ratio by weight. A place name alone cannot tell you how wet the starter is or when it will peak. Once you know its hydration, you can make feeds more predictable and adjust recipes with less guesswork.
I often see bakers focus on the latest feed and overlook the starter already in the jar. That can skew the calculation. The method below accounts for the starter’s existing flour and water, then gives you a reliable baseline to maintain.
Starter Vessel, Flour, and Water Setup
A consistent starter begins with accurate weighing, clean tools, and a suitable container. Use a clean glass or food-grade plastic jar, or mix briefly in sound stainless steel. Avoid copper and unlined aluminum, which can react with an acidic starter. Choose a jar with room for the starter to rise.
Use a digital kitchen scale and potable water. Flour type affects how quickly a starter ferments and how it looks, so note what you use. You can maintain a 100%-hydration starter with many flours, but changing flour may change its speed, smell, and texture.
Choose a jar and mark the starting level
A jar should leave ample headroom after feeding. The starter may rise and then fall, so a mark at its starting level helps you track the change. A rubber band or washable marker can show the level just after feeding. Do not fill the jar to the top.
Keep the jar and utensils clean. A clean jar makes it easier to see activity and limits dried starter from building up along the sides. Wash with warm water and detergent when needed, then rinse well.
Choose flour and water by weight
For a 100%-hydration starter, weigh flour and water in equal amounts. For example, mix 50 g water with 50 g flour. Do not assume that equal cup measures weigh the same: flour can pack differently, and volume measures can shift the hydration.
Use potable water. If you change flour or water source, observe the starter over several feeds before changing the feeding schedule. Keep notes on the amounts, room temperature, and time it takes to rise. Next step: weigh every feed and mark the jar.
Hydration, Feeding, and Fermentation Execution
Hydration is the weight of water divided by the weight of flour, multiplied by 100. At 100% hydration, water and flour weigh the same. To calculate it correctly, include the flour and water already in the starter, not just the latest feed.
A 100 g portion of 100%-hydration starter contains 50 g flour and 50 g water. If you add 100 g water and 100 g flour, the total starter still has equal weights of flour and water. This accounting matters when adapting a recipe or correcting a starter that was fed by volume.
Calculate a feed by weight
A 1:2:2 feed means one part starter, two parts water, and two parts flour by weight. For a simple example, use:
- 20 g starter
- 40 g water
- 40 g flour
If the 20 g starter is at 100% hydration, it contains 10 g flour and 10 g water. After feeding, the total is 50 g flour and 50 g water, so the mixture remains at 100% hydration.
A 1:2:2 feed is a maintenance option, not a promise of a fixed rise time. A different feed ratio changes how much fresh flour and water the starter receives. Keep the ratio consistent when you want to compare activity from one feed to the next.
Mix and track activity
Add the weighed water and flour to the weighed starter, then mix thoroughly. Scrape down the sides and mark the starting level. Cover the jar loosely, or use a lid that is not sealed under pressure. An actively fermenting starter can produce gas, so it should not be kept in a pressure-tight container.
For predictable room-temperature activity, aim for about 24–26°C (75–79°F). This is a target, not a guarantee of a particular rise time. Starter strength, flour, and room conditions all affect how fast fermentation proceeds. Watch the starter rather than relying on a fixed number of hours.
A starter that has risen and shows bubbles is active, but the best time to use it depends on the recipe and the rise pattern you observe. Record when it rises and when it begins to fall. Next step: use your own rise pattern as the timing guide.
Diagnose a starter that seems too stiff or runny
A thick or loose starter does not always mean it is unhealthy. Hydration may be off because flour and water were measured by volume, or because the existing starter was not included in the calculation. Flour type and fermentation stage can also affect how the mixture looks.
| What you notice | Likely factor to check | Practical response |
|---|---|---|
| Very stiff after a feed | Water may have been under-measured | Weigh the next feed; check total flour and water |
| Much looser than expected | Water may have been over-measured | Calculate hydration across the whole starter |
| Rise timing changed after a flour switch | Flour may ferment or absorb water differently | Keep the feed ratio steady and track the new pattern |
| Starter rose, then sank | It may have passed its highest rise | Feed again and note the time to rise and fall |
Do not correct a starter by adding flour or water without weighing it. That makes the next hydration calculation harder. If the starter’s current ratio is unknown, weigh what you have and use a measured feed to bring it toward equal total flour and water.
Storage, Cleaning, and Starter Maintenance
Storage affects how often you need to feed a starter, but cold does not stop fermentation completely. Refrigeration at or below 4°C (40°F) slows activity; it does not sterilize the starter. Keep using clean tools and a suitable container, whether the starter is on the counter or in the fridge.
For room-temperature maintenance, feed by weight and observe the rise before the next feed. If you bake less often, refrigerating between uses can reduce how often you need to refresh it. When you take it out, feed it and allow it to become active before relying on it in a recipe.
Refrigerate between less-frequent bakes
Use a lid that protects the starter while avoiding a pressure-tight seal during active fermentation. If you have just fed the starter, leave enough headroom for it to rise. Keep the jar cold at 4°C (40°F) or below.
The time needed for a refrigerated starter to become active again varies. Check for visible rise and bubbles after feeding rather than assuming it is ready after a set interval. If you need a predictable schedule, plan a room-temperature feed and track how long your starter takes to rise under those conditions.
Clean and refresh the container
When you refresh the starter, retain a measured portion and feed it again. Wash the container with warm water and detergent as needed. Avoid sudden hot-to-cold temperature changes with glass, since abrupt temperature shifts can damage it.
Discard starter that shows fuzzy mold or pink or orange discoloration. Do not try to remove only the visible patch and keep the rest. A sour smell alone is not the same visual warning, but if you see mold or pink/orange color, discard it and clean the container before starting again.
Next step: choose either a tracked room-temperature routine or a cold-storage routine, then keep the feed ratio and notes consistent.
Using the Starter and Presenting the Finished Bread
Use the starter when it is active and at the stage your recipe calls for. A recipe may expect a recently fed starter or one near its highest rise, so follow its timing cues when provided. Hydration helps you understand the mixture; it does not, by itself, tell you whether fermentation is complete.
A common source of confusion is treating starter weight as all flour. For example, 100 g of 100%-hydration starter contributes 50 g flour and 50 g water to a dough. If a formula needs precise dough hydration, include those amounts in the total flour and water.
Adjust a recipe with starter contributions
If a recipe uses 100 g of 100%-hydration starter, count 50 g flour and 50 g water from that starter. If the recipe calls for a different starter hydration, calculate its flour and water before changing the dough ingredients. This prevents hidden extra water or flour from shifting the dough.
Do not assume a starter from a particular neighborhood, bakery, or household has a known hydration. Ask for its feeding weights or measure and calculate the ratio. If no feeding details are available, treat its hydration as unknown until you can establish it through weighed ingredients.
Practical troubleshooting scenarios
These are common situations to use as checks, not claims about a specific bakery or named starter:
- You inherited a jar with no feeding notes. Weigh the starter and ask how it was fed, if possible. A sample’s total hydration cannot be known from its appearance alone.
- Your starter turned runny after a cup-based feed. Switch to grams and calculate the water and flour already present. Avoid adding flour by eye.
- Your starter behaves differently after moving to a warmer kitchen. Keep the feed ratio steady, note the new temperature, and observe its rise. Activity may speed up in warmer conditions.
- You bake only now and then. Store the starter at or below 4°C (40°F) between uses, then feed and wait for visible activity before baking.
A steady process is more useful than trying to force every starter to look identical. Key takeaway: weigh the starter and every feed, then let visible activity guide when you use it.
Conclusion
A dependable 100%-hydration starter comes from a simple habit: track the flour and water in the whole mixture. Use a 1:2:2 feed by weight when it suits your schedule, keep the starter in a clean, nonreactive container, and observe how it rises at your room temperature.
If “Kensington Market” refers to a specific starter, ask its baker for the feeding ratio and flour details. The name cannot establish hydration. Once you know the weights, you can maintain the starter and account for it in bread recipes.
Frequently Asked Questions
These quick answers cover the main hydration and care questions. When a starter’s flour, feed history, or temperature is unknown, use weighed ingredients and observed activity rather than guessing. The same approach helps you compare feeds and make sensible adjustments.
What does 100% starter hydration mean?
It means the starter contains equal weights of water and flour. A starter with 100 g flour and 100 g water is at 100% hydration.
How do I calculate sourdough starter hydration?
Divide the total water weight by the total flour weight and multiply by 100. Include the water and flour already inside the starter.
How much flour and water are in 100 g of 100%-hydration starter?
It contains 50 g flour and 50 g water. That assumes the starter is truly at 100% hydration.
What is a 1:2:2 starter feed?
It is one part starter, two parts water, and two parts flour by weight. With a 100%-hydration starter, equal water and flour additions preserve 100% hydration.
Can I feed sourdough starter with cups?
For consistent hydration, weigh the ingredients instead. Cup measures can vary in weight, which may make the starter too stiff or too loose.
What temperature should I use for room-temperature fermentation?
About 24–26°C (75–79°F) is a useful target for predictable activity. The time to rise still varies with starter strength, flour, and room conditions.
Can I refrigerate my starter?
Yes. Refrigeration at or below 4°C (40°F) slows activity and can suit less-frequent baking. It does not sterilize the starter.
Should I seal an active starter in an airtight jar?
No. Use a loose cover or a lid that is not sealed under pressure. Fermentation produces gas, and an actively fermenting starter should not be pressure-tight.
When is my starter ready to use?
Use it when it is active and fits the timing cues in your recipe. A visible rise and bubbles are useful signs, but rise time varies, so track your starter.
When should I discard a starter?
Discard it if you see fuzzy mold or pink or orange discoloration. Clean the container before starting again.
(This article was written by one of our staff writers, Andrew P. Morrison. Visit our Meet the Team page.)
