How to Rehydrate a Dehydrated Sourdough Starter (Step by Step)

So your dehydrated sourdough starter just arrived in the mail. Now what?

First off, congratulations. You're about to bring something really special back to life. Whether you picked up one of our heritage San Francisco starters, the 4,500-year-old Egyptian culture, or any other variety, the process is the same. You're going to take what looks like a little bag of dried flakes and turn it into a bubbling, alive sourdough starter that you can bake with for the rest of your life.

I've walked thousands of customers through this process, and I want to be upfront with you: it's not hard. It does take a little patience (about 5 days), but if you follow along here, you'll be just fine. And if anything goes sideways, you can always message me directly for help. I usually respond within minutes.

Let's get into it.

Before You Start: What You'll Need

Gather these up before Day 1 so you're not scrambling mid-process:

• A 16 oz glass jar (a Ball jar with a lid works great). You'll also want a larger 32-64 oz jar ready by Day 5 when things start to grow.
• Filtered tap water or spring water. This is important. Avoid distilled water, purified bottled water, and reverse osmosis water. These types have had the minerals stripped out, and your starter needs those minerals to thrive. Regular filtered tap water from a Brita or your fridge dispenser is perfect.
• Unbleached bread flour is my top recommendation. All-purpose flour works too. If you're going gluten-free, use the GF flour of your choice.
• A mixing utensil. Avoid metal if you can. A wooden spoon, silicone spatula, or one of our glass stir rods all work great.
• A kitchen scale. This isn't 100% required, but I really recommend one. Weighing your flour and water in grams is so much more accurate than measuring cups, and it makes a noticeable difference in consistency. You can grab a basic digital scale for about $10 on Amazon.

The #1 Mistake Beginners Make (Read This First)

Before we jump into the day-by-day process, I want to tell you about the single most common problem I see with new sourdough bakers. It comes up constantly, especially during the warmer months.

The mixture is too thin.

When your starter is too runny or watery, the bubbles that form just float up to the surface and pop. That means the gas escapes instead of getting trapped inside the starter. So it looks like nothing is happening, even though the yeast is actually active and doing its job. The starter just can't rise because it doesn't have enough structure to hold the bubbles in.

The fix is simple: add more flour. Your starter should have the consistency of a very thick paste after every feeding. Think thick enough that it's hard to stir, and it holds a blob shape on the spoon for a second before slowly falling off. If it pours like pancake batter, it needs more flour.

The second most common issue is temperature. In cold kitchens (especially in winter), the starter just doesn't have enough warmth to get going. I'll cover how to handle that below.

Day-by-Day Rehydration Guide

Try to start this process in the morning. Your starter will typically hit its most active point about 4 to 6 hours after a feeding, so morning starts mean you can watch the action happen during the day instead of missing it overnight.

Day 1: Wake Her Up

Empty the contents of one packet of dehydrated starter into your glass jar. Add 30 grams (about 2 tablespoons) of warm water and give it a stir. Let it sit for about an hour so the dried flakes can begin to soften and absorb the water.

After that hour, add 15 grams (about 2 tablespoons) of flour. It's totally fine if the dehydrated pieces haven't fully dissolved yet. They will over time. Just stir until all the flour is mixed in and there are no dry patches.

Cover the jar loosely (set the lid on top without screwing it down, or drape a clean cloth over it secured with a rubber band) and leave it at room temperature for 24 hours.

Not much will happen today, and that's completely normal. Your starter is just waking up.

Day 2: First Real Feeding

After 24 hours, it's time for the first proper feeding. Add 15 grams of flour and 15 grams of warm water. That's equal parts by weight.

Here's the key thing to remember from today forward: after every feeding, you want the consistency to be a very thick paste. It should be difficult to stir. It should hold a blob or ball shape after stirring, and then slowly settle into the jar over the next 30 minutes or so. If it seems runny or thin, just add a touch more flour until you get there.

Stir it well, cover loosely, and leave it for another 24 hours.

Day 3: Signs of Life

Add 30 grams of flour and 30 grams of warm water.

By now, you might start seeing the first signs of activity. Look for small bubbles forming in the mixture. Even just a few tiny bubbles means the wild yeast is waking up and starting to feed. That's exactly what we want.

If you don't see anything yet, don't panic. Some starters take a little longer depending on your environment, the temperature in your kitchen, and the flour you're using. Just keep going.

Stir, cover loosely, and wait another 24 hours.

Day 4: Things Are Getting Real

Today you might notice something cool. The starter may have risen up in the jar and then collapsed back down, leaving streaks or residue on the inside walls of the glass. That's a great sign. It means the yeast was active enough to make the mixture rise, it just ran out of food and fell.

Time for a bigger feeding. Add 60 grams of flour (about half a cup) and 60 grams of warm water (about a quarter cup). If the texture feels too thick, that's actually perfect, as long as there are no dry pockets of flour hiding in there. Environmental factors like humidity can slightly change how much water you need, so just use your judgment.

Stir thoroughly, cover loosely, and let it rest for another day. If your jar is getting full, go ahead and transfer the starter into a bigger container.

A note on twice-daily feedings: Some starters get really active around Day 4, especially if your kitchen is warm or you're using a lower-protein flour. If you notice the starter rising and falling within 8 to 12 hours, you can start feeding it twice a day (roughly every 12 hours) to keep it well-fed and happy.

Day 5: Almost There

If you haven't already, now is the time to move your starter into a larger container, something in the 32 to 64 oz range. Here's a handy tip: weigh the empty jar and write that number on it with a marker. Later, when you need to discard before feeding, you'll be able to set the jar on your scale and know exactly how much starter is inside.

For today's feeding, add 60 grams of flour and 60 grams of room temperature or slightly warmer water. If it's too thick, slowly add water by the teaspoon until you get that familiar thick-paste consistency.

Keep the jar in a warm spot (ideally between 70 and 80°F, or 21 to 27°C). Within 4 to 6 hours, you should see some serious rising and bubbling.

The moment it doubles in size within that 4 to 6 hour window after feeding, your starter is officially ready to bake with. That's it. You did it.

Keeping Your Starter Alive: Ongoing Care

Now that your starter is active, here's how to keep it that way long term. You have two options depending on how often you bake.

If you bake often (daily or every couple of days): Keep your starter at room temperature and feed it once a day. Before each feeding, discard enough starter so only about a quarter of the jar remains. (Don't throw the discard away! Save it in a separate container for discard recipes like pancakes, crackers, and pizza dough.) Then feed with equal parts flour and water by weight to match the remaining starter. That's the classic 1:1:1 ratio (starter, flour, water).

If you bake less often: Store your starter in the refrigerator with the lid tightened. Feed it before putting it in the fridge, and then feed it again every 7 to 10 days to keep it healthy. When you're ready to bake, pull it out, discard, and feed it at room temperature for 1 to 2 days until it's doubling reliably within 4 to 6 hours again.

A healthy starter can hang out in the fridge for up to a month or more without feeding if needed. Every week is ideal, but these cultures are incredibly resilient. Don't assume yours is dead just because it's been sitting in the back of the fridge for a while. Feed it and give it a chance.

Troubleshooting: Common Issues and Quick Fixes

"My starter looks completely inactive."
It's probably just too cold. The ideal temperature range is 70 to 80°F. If your kitchen runs cool, try placing the jar on top of your refrigerator, near (not on) a heating vent, on top of an espresso machine, or in your oven with just the light turned on. You can also use a seedling heat mat. If any of these run too hot, stack a ceramic plate or two between the heat source and the jar to bring the temperature down.

Also, try to keep the jar elevated off granite countertops or stone surfaces. They pull heat away from the jar faster than you'd think.

"There's a layer of liquid on top."
That dark liquid is called "hooch," and it's totally normal. It's an alcohol byproduct of fermentation, and it's actually a sign that things are working. It just means your starter is hungry. Pour off about half of the hooch (or stir it back in) and give the starter a good feeding. It should bounce right back.

"The starter rose and fell and now it looks deflated and smells strong."
This is normal and actually a good thing! It means the starter was active, used up all its food, and is now waiting to be fed again. That strong, almost vinegary smell is what a hungry starter smells like. Feed it and it'll perk right back up.

"My starter is too thin and bubbly on top but not rising."
This is the #1 issue I mentioned at the top. The mixture doesn't have enough structure to trap the gas bubbles. Add more flour at your next feeding. Try a 1:3:2 ratio (1 part starter, 3 parts flour, 2 parts water) instead of the standard 1:1:1. That extra flour will give the starter the body it needs to rise.

"It's been 5 days and nothing is happening."
Don't give up. Some starters, especially in cold environments, can take 7 days or even a bit longer. Make sure you're using warm water (75 to 80°F is ideal) and keeping the jar in a warm spot. If you're still stuck, reach out to us. Seriously. We'll help you figure out what's going on.

A Few Things to Keep in Mind

Water matters. Chlorine in tap water can slow down or harm the microbes in your starter. Filtered tap water takes care of this. If your water smells like a swimming pool, definitely filter it first or let it sit out uncovered for a few hours so the chlorine evaporates.

Flour matters too. Unbleached bread flour gives the best results because it has a higher protein content, which gives your starter more to feed on. All-purpose works fine, but if your starter seems sluggish, switching to bread flour can make a real difference.

Temperature is everything. This is probably the single biggest variable that affects how fast your starter activates. A warm kitchen (75 to 80°F) will get you to baking day faster. A cool kitchen (below 68°F) will slow everything down. It doesn't mean anything is wrong, it just means you need to be a little more patient or find a warmer spot for the jar.

Your starter is tougher than you think. I cannot stress this enough. These cultures have survived for decades, centuries, and in some cases thousands of years. A few rough days in your kitchen are not going to kill them. If you ever think your starter is done for, please message us before you throw it away. We've revived starters that customers were sure were goners.

You're Ready to Bake

Once your starter is reliably doubling within 4 to 6 hours of feeding, the world of sourdough is wide open. Crusty artisan loaves, soft sandwich bread, tangy pizza dough, fluffy pancakes, and so much more.

Give your starter a name. It sounds silly, but it makes the whole process more fun. You're going to be feeding this thing for years to come, so it might as well have a personality.

For recipes, tips, videos, and ongoing support, visit us at grtgrandmas.com. And if you ever get stuck or have a question, no matter how small, reach out. That's what we're here for.

Happy baking.