How to Activate Your Sourdough Starter
How to Activate Your Sourdough Starter: A Step by Step Beginner’s Guide
The Short Answer
To activate a sourdough starter, place it in a clean glass jar and feed it with equal parts flour and water by weight, a 1-1 ratio. Keep it at 18-22°C and feed once or twice daily until it is bubbly and doubling in size reliably. Most NutriBrew live starters show strong activity within 1-3 days of arrival. Once active, your starter is ready to bake with.
In This Activation Guide
Your NutriBrew sourdough starter has just arrived. It has been travelling, it is slightly dormant, and it needs a feed before it is ready to bake with. The good news is that activating a live wet starter is straightforward once you understand what the culture needs and why.
This guide walks you through every step, from the moment your starter arrives to the moment it is bubbly, active and ready to leaven your first loaf. We cover feeding ratios, temperature, storage, which flour to use for each variety, and what to do if things do not look quite right in the first few days.
Not sure what a sourdough starter actually is yet? Read our complete sourdough starter guide first, then come back here when you are ready to activate.
Important: Use Organic Flour Where Possible
Non organic flours can contain pesticide residues that stun or kill delicate wild yeast strains during the fragile activation phase. Organic flour gives your starter the cleanest possible environment to wake up and thrive. If organic flour is not available to you, unbleached non organic flour is the next best option. Avoid bleached flour entirely during activation.
Before You Start: What You Need
You do not need much to activate a sourdough starter. Keep it simple, especially in the first few days.
What You Need
- A clean glass jar, sterilised with boiling water and fully cooled before use
- Organic flour, the type depends on your starter variety, see the flour guide below
- Filtered or still mineral water, tap water can contain chlorine which may slow activation
- Kitchen scales, feeding by weight rather than volume gives consistent results
- A wooden or plastic spoon, avoid metal utensils as they can affect the culture
- A loose lid or breathable cloth, the starter needs air but not dust or flies
- A warm spot in your kitchen, ideally 18-22°C
NutriBrew Tip: Place a rubber band around your jar at the level of your starter after feeding. This makes it easy to see exactly how much it has risen without having to guess. When it has doubled or more above the band, it is at or near its peak.
Step by Step Sourdough Starter Activation
Follow this sequence within 48 hours of your starter arriving. The culture has been travelling and needs feeding as soon as possible to wake it up properly.
Activation Steps for an 80g Starter
Step 1: Prepare your jar
Sterilise a glass jar with boiling water and allow it to cool completely before use. Residual bacteria from an unwashed jar can compete with the sourdough culture for nutrients and weaken its activity.
Step 2: Add your starter
Empty your 80g starter into the clean jar. Scrape out as much as possible from the packaging.
Step 3: Feed with flour and water
Add 40g of organic flour and 40g of filtered water. This is a 1-1 ratio by weight, equal parts flour and water. Mix thoroughly until no dry flour remains. The 1-1 ratio wakes the yeast without overwhelming the colony with too much new material at once.
Step 4: Cover and keep warm
Cover loosely with a cloth or a lid that is not fully sealed and place in a warm spot at 18-22°C. Mark the level with a rubber band so you can track the rise.
Step 5: Feed once or twice daily
Repeat the feeding process once or twice every 24 hours. Each time you feed, discard half the starter first to prevent the jar from overflowing and to keep the culture well nourished. See the maintenance cycle section below for exactly how to do this.
Step 6: Watch for activity
Within 1-3 days you should see bubbles forming throughout the starter and it should begin to rise after feeding. Once it is reliably doubling in size within 4-8 hours of a feed and smells pleasantly tangy or yeasty, it is ready to bake with.
Activation Steps for a 160g Starter
The process is exactly the same as above. Scale your flour and water proportionally, keeping the 1-1 ratio. For a 160g starter add 80g flour and 80g filtered water per feed. The larger volume simply means more material to feed at each stage. Everything else, temperature, frequency, timing and signs of activity, remains the same.
Sourdough Starter Feeding Ratios Explained
Understanding feeding ratios takes the guesswork out of maintaining your starter. The ratio refers to the balance of starter, flour and water by weight at each feed.
| Ratio | For 80g Starter | When to Use |
|---|---|---|
| 1-1 ratio | 80g starter, 40g flour, 40g water. Half the weight of your starter in flour and water | Daily feeding at room temperature, standard maintenance |
| 1-1-1 ratio | 80g starter, 80g flour, 80g water. Equal weight of flour and water to match your starter | After fridge storage, after hooch appears, reviving a slow starter |
| 1-2-2 ratio | 80g starter, 160g flour, 160g water. Double the flour and water to slow the cycle down | Warm kitchens above 22°C where the starter moves through its cycle too fast |
| Skip discard | Keep all 80g starter, add 40g flour and 40g water without removing anything first | When you need more starter volume for a large recipe |
The Maintenance Cycle: Discarding and Feeding
Once your starter is active, the maintenance cycle keeps it healthy and prevents it from becoming overpowered by its own waste products. The most common beginner mistake is skipping the discard step.
If you do not remove some starter before feeding, the yeast population becomes too large to be sustained by small amounts of flour. The culture becomes overly acidic, weak and unreliable for baking.
The Daily Maintenance Routine
Discard: Remove 50% of your starter from the jar. Do not throw this away, sourdough discard is excellent in pancakes, crackers, flatbreads and pizza dough.
Feed: Add equal parts flour and water to what remains. If you kept 40g of starter, add 40g flour and 40g water.
Mix: Stir thoroughly until fully combined and no dry flour remains.
Observe: Mark the level and watch for doubling. A healthy active starter is ready to bake with when it doubles within 4-8 hours of feeding.
NutriBrew Tip: Keep your discard in a separate jar in the fridge. It builds up quickly and can be used in a wide range of recipes. You will never need to throw away a single gram of your starter once you get into the habit.
How to Store Your Sourdough Starter in the Fridge
If you are not baking every day, the fridge is the best place to keep your starter between bakes. Cold temperatures slow the fermentation cycle right down, meaning you only need to feed it once a week to keep it alive and healthy.
Fridge Storage Routine
Storing: Feed your starter, leave at room temperature for 1 hour to get the yeast working, then seal tightly and place in the fridge.
Weekly maintenance: Feed once a week to keep the culture alive. You do not need to bring it fully to room temperature first, just feed it and return it to the fridge.
Before baking: Remove from the fridge 1-2 days before you want to bake. Feed once or twice daily at room temperature to bring it back to full activity before using in a recipe.
Heirloom strength: A sourdough starter gets stronger and more characterful with age. A NutriBrew starter that has been fed and baked with for 6 months will be significantly more resilient and flavourful than a 1 week old culture.
💧 What is the Dark Liquid on Top of My Starter?
This is called hooch. It is alcohol produced by hungry yeast and it looks alarming but is completely harmless. Simply pour it off, then feed your 80g starter on a 1-1-1 ratio (80g starter, 80g flour, 80g water) for 2-3 days to bring it back to full strength before baking.
Which Flour to Use for Each Sourdough Starter Variety
Feeding your starter with the right flour keeps it at its most active and consistent. Each of our heirloom varieties performs best with a specific flour type.
| Starter Variety | Best Flour for Feeding | Notes |
|---|---|---|
| San Francisco | Strong white bread flour | High vigor, needs headroom in the jar |
| Alaskan | Strong white bread flour | Cold resilient, performs well in cooler kitchens |
| Classic White | Strong white bread flour | The most versatile everyday starter |
| Old World Rye | White or wholemeal rye flour | Dense and fibrous on arrival, very active once awake |
| Colorado Brown | Wholemeal flour | Slower to peak due to bran content, worth the wait |
| Gluten Free | Brown rice flour or oat flour | Different texture and bubble pattern to wheat starters, both are normal |
Sourdough Starter Troubleshooting
Most issues with sourdough starters come down to temperature, feeding frequency or flour choice. Here are the most common problems and straightforward fixes.
| Problem | Likely Cause | Fix |
|---|---|---|
| No bubbles after 3 days | The starter is still recovering from its journey. This is completely normal. | If there is still no activity after 5 days, switch to 1-1-1 ratio, 80g starter, 80g flour, 80g water for the next 2-3 feeds. |
| Bread tastes too vinegary | Starter was exhausted or over proofed dough | Feed twice daily and use starter sooner after its last feed, at peak not past it |
| Starter smells of acetone or nail polish | Underfed or too warm | Increase feeding frequency and move to a cooler spot |
| Dark liquid on top | Hooch, starter is hungry | Pour off the liquid and resume a 1-1-1 feeding schedule for 2-3 days |
| Bread not rising properly | Starter not at peak activity when used | Feed daily for 2-3 days before baking and use at the peak of its rise, not after it falls |
| Pink, orange or fuzzy growth | Contamination or mould | Discard entirely and start fresh. Do not bake with a contaminated starter |
| Need more starter for a recipe | Not enough volume built up | Skip the discard step for 1-2 feeds to double the volume quickly |
Frequently Asked Questions About Activating a Sourdough Starter
How long does it take to activate a sourdough starter?
Every live culture needs time to settle after shipping. This is completely normal and not a sign that anything is wrong. Most NutriBrew starters show their first bubble activity within 3-5 days of arrival when kept at 18-22°C and fed once daily. Give it time to settle into it’s new environment, it will get there.
Can I use tap water to feed my sourdough starter?
Tap water can work but filtered or still mineral water gives better results, particularly during activation. Chlorine in tap water can slow down wild yeast activity. If tap water is all you have, leave it in an open container for a few hours before using to allow the chlorine to dissipate.
What temperature should my sourdough starter be kept at?
The ideal range is 18-22°C. Below 16°C the starter becomes very slow and may appear inactive. Above 25°C it moves through its feeding cycle too quickly and can become overly acidic. Temperature is the single biggest variable in how your starter behaves, so if things seem off, check your kitchen temperature first.
Is sourdough starter vegan?
Yes. Our sourdough cultures contain only flour, water and wild captured microorganisms. No animal byproducts are used at any stage.
How do I know when my starter is ready to bake with?
Your starter is ready when it doubles in size reliably within 4-8 hours of feeding, has bubbles throughout, smells pleasantly tangy or yeasty, and passes the float test where a small spoonful dropped in water floats. Use it at or just before its peak for the best rise and flavour in your bread.
Have more questions about your sourdough starter?
Visit our dedicated sourdough starter FAQ page for answers to every common question about feeding, storing, baking and troubleshooting your NutriBrew starter.
Everything You Need for Sourdough Success
From choosing your starter to baking your first loaf, our guides cover every step of the journey.