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beginner's guide to creating and maintaining sourdough starter

cranbo's picture

beginner's guide to creating and maintaining sourdough starter

There's quite a few good tutorials on this on TFL, but tons of lousy ones online, but I thought I would add my own. Mine is a bit different than others in that it focuses on maintaining warm temps throughout the starter creation process. I believe this is key to establishing good yeast and bacterial multiplication and a healthy starter ecosystem. It also focuses on just using flour, water, time and temperature to build a starter. No sugar, potatoes, honey, (heaven forbid) commercial yeast, other fancy stuff. Be patient, pay attention (look, smell, taste, and take good notes) and you will be rewarded with a strong, tasty starter. 

You'll need:

  • A quart-sized Ziploc bag (or other clear plastic or glass container)
  • A bowl (optional, to contain the Ziploc bag in case it leaks) 
  • An instant read thermometer (that provides accurate temperature between 60 - 110F) 
  • Whole wheat (or rye) flour (organic is nice but not required)

Day 1

To the Ziploc bag, add: 

  • 1/2c whole wheat (or rye) flour 
  • 1c very warm water (98F) 

Thermometer in starter

Get as much air as you can out, zip it up, and squish the mixture around. 

sourdough starter in ziploc bag with flour

Now put it in a very warm place (but not in direct sunlight!) between 85-99F...this is important. If your house isn't warm enough, you can place your starter in your oven with the oven light on. Or you can use a heating pad. Use your thermometer to check the ambient temperature where you are keeping it. You don't want it to get hotter than 100F, otherwise this has a negative impact on yeast and lactic acid bacteria development: any hotter and you risk killing them.

starter ziploc bag in ceramic bowl in oven with light on

Let the Ziploc rest in this warm place for 24 hours. Relax and congratulate've taken your first steps towards a healthy starter. 

Day 2

Your starter might look fizzy or foamy today. That's good; if it doesn't, don't worry about it. It's time for its first feed. Beware, it may smell vomit-like and be gag-worthy. Don't sweat it, this is normal; pinch your nose or breathe thru your mouth if it bothers you. 

sourdough starter day 2, foamy and smelly

To the Ziploc, add: 

  • 1/2c whole wheat (or rye) flour

day 2 sourdough temp reads 93.4F

Again, squeeze the air out, seal the bag, then squish the mixture around again. Let it again sit between 80-99F for 24 hours. 

Day 3

Give the bag 1-2 shakes to distribute mixture.  Check how it smells. Should be somewhat less vomit-like at this point. If you're lucky, it may start to smell a little vinegar-like, or like sharp cheese (like Parmigiano), or beer like. If it still smells vomit-y, don't worry about it. Over the next 2-3 days, with subsequent feedings, this smell will pass. 

day 3 sourdough starter, puffy and smelly

liquid separation on day 3 sourdough

The mixture might look separated, as in the above photo. That's OK, don't sweat it, just give the whole thing a couple of shakes to distribute the mixture again. Now reserve 2 tablespoons of the starter, and dump the rest out down the drain or in the trash.

To the emptied Ziploc, now add:

  • 2 tbsp of the reserved starter
  • 1/4c. warm water (98F)
  • 1/2c. whole wheat flour 

Seal the bag again, squish it around, let it sit at a comparatively cooler (but still warm) room temp (75-85F) for 24 hours. 

Day 4

Today your starter may be starting to show signs of life. This is when you start your regular feed cycle. It's also a good time to transfer your starter to a new container, like a large mason jar, or a plastic quart deli container, or other plastic container. Just don't seal the lid tight, it could pop! 

From here on our, you want to feed once or twice per day, as follows: 

  1. Toss all but 2 tbsp of your starter in the trash
  2. To your reserved starter, add 1/4 c. warm water (85-90F), and stir to combine
  3. Feed it 2/3c. whole wheat flour. 
  4. Store it at warm room temp (70-85F) 

Always try to feed your starter at the same time of day. For this and subsequent feedings, your starter will look pretty thick and pasty, like this:

Day 5, 6, 7: continue feed in the same way as described in Day 4 above.

This is what mine looked like on Day 7. Notice the nice air bubbles and pockets visible on the side and bottom of the container: this means your starter is active and ready to use. Don't worry if this doesn't happen for you on Day 7. Be patient, and keep going (as directed) through Day 11, and in that time you will have an active starter that looks like this. 


ready to use, bubbly sourdough starter

Day 8, 9, 10: feed in the same way as Day 4. Your starter should be pretty active by now. Start keeping track of how long it takes for the starter to double. Record the time you feed, and how much it rises. You are aiming to get it to double within 4-6 hours. When it does this, the starter is ready to use. 

Day 11: you can switch to feeding with all-purpose flour or a 50/50 combo of whole wheat and all-purpose flour, if desired. Whole wheat will give a more sour flavor to your starter.

By this point your starter should be quite active and ready to use in your recipes. It will be more active if you feed it 2x per day. It will be more active if you keep it at a warmer room temp (between 75-80F). If you only feed it once per day, it will generally take much longer to leaven your bread. 

Frequent Issues or Problems:

If you ever get black or fuzzy mold, scrape it off, and save a tablespoon or two of the clean starter. Then transfer it to a clean container and feed it. 

Don't store your starter in the fridge. You can if you have to (it is more convenient if you're not baking), but it will change the flavor. If you do, pull it out of the fridge 2 days before baking, and feed it at least 2x over those 2 days before baking. 

After Day 4, you can feed smaller amounts if you're concerned about waste. You can reserve 1 heaping tablespoon of starter, 2 tbsp water, and 1/2c. flour for your daily (or twice daily) feeds. 

Problems? Successes? Questions? Comments? Post them here. 


dabrownman's picture

is making the initial mix include 1 T of orange juice, a pinch of cumin and sub 1/8th C of rye for the WW - all the grains should be fresh milled too.   82 F is best for yeast and the labs together.  Labs, while liking a higher temperature of 88 F,the yeast doesn't.  these changes  would just speed everything up and insure a successful starter.

Also the only things I have noticed about storing starters in the fridge after they are established is that they require much less maintenance, are not as wasteful and the sour is much better as labs reproduce 3 times faster at 36F then yeast does.  If you don't want sour, donlt mind the waste and enjoy feeding it all the time, then keep the starter at room temperature on the counter.    I've done it both ways for decades, both liquid and stiff, and I will never keep a starter on the counter except while feeding it and getting it ready for the fridge from now on.  Others don'l like sour so the fridge isn't for them.

Happy baking 

cranbo's picture

Thanks dabrownman. The juice and cumin are good suggestions. I haven't read enough about the cumin, I know it's another source to establish yeast & LAB, correct? Can you point me to an article? I don't disagree with the benefits of initial acidification (a la Debra Wink), but I don't think it's absolutely necessary (although it can't hurt, and that can be a benefit for beginners). 

I'm not sure I completely agree with the cold storage, although it's commonly expressed, I wonder in practice how much difference it makes. The sour I was able to achieve with this method was significantly more sour stored at room temp then in the fridge. As soon as I stored it in the fridge, even just 12 hours, it changed significantly, and took a while at room temp feedings to spring back. 

Here's some research to back up warm weather storage, and a short synopsis of the results: 

2 strains of Lactobacillus sanfranciscensis have optimum growth rate at 32-33C (89.6F - 91.4F)

Optimum growth rate for C. milleri yeast was 27°C (80.6F) 

So if you are trying to build more LABs, warmer temps might do the trick as well. And starting a new starter at really warm temps should help LABs growth, which should help initial acidification & culture establishment: 

Would love to hear some more thoughts on this approach



dabrownman's picture

for reproductive rates of labs and yeast.  The optimum temperature for yeast is 82 F and the optimum for labs is 91 F.  You will also see that although the rates slow down considerably at 36 F for both labs and yeast the labs are reproducing 3 times faster than the yeast at that temperature.  The longer you hold your starter at 36 , within reason since yeast only live 7-8 day,  the more labs you will inoculate into your dough.  At 36 F You will produce the same amount of labs in 20 hours as you would 1 hour at 72 F but the yeast would need 60 hours to produce the same amount of yeast at 72 F in 1 hour.  So if you refrigerate your starter for 3 days, you will be inoculating your dough with roughly 3 times the amount of labs as yeast  than you would normally and your bread should be noticeably more sour.  My own baking experiments with starters and temperature seems to prove this out.

Additionally, if ypou proof at a high temperature say 86 F the yeast will also slow down as the Labs speed up to make an even more sour bread.  Long cold retards of starters levains and dough with a high temp final proof should always make for the most sour bread that your starter is capable of making using the flours and hydration of your choosing.

It's just science and luckily for us, yeast has been experimented on the most my scientists over the years, by a wide margin, so we know much more about yeast than any living thing.

Joe Ortiz uses a little cumin and milk along with whole wheat and water for his starter.  I have tried it several times and it always works for me and is the fastest to make bread - 4 days.  Not only does the cumin have wonderful natural yeast on the seeds you grind but the cumin supposedly has antiseptic qualities that reduce the bad bacteria  population allowing the good stuff a leg up and allowing them to cultivate faster.

Reproduction Rates of Labs and YeastL/Y 
T(°F)T (°C)L. SF IL. SF IIYeastRatio
     36        2 0.0190.0160.0053.787
     46        8 0.0470.0430.0212.222
     61      16 0.1440.1500.1141.265
     64      18 0.1870.1980.1631.145
     68      20 0.2390.2590.2251.064
     72      22 0.3010.3320.2951.021
     75      24 0.3740.4160.3651.024
     79 260.4530.5080.4141.094
     82      28 0.5350.5980.4171.284
     86      30 0.6090.6720.3461.760
     90      32 0.6580.7060.2023.255

Happy baking

cranbo's picture

Cool chart, thanks for sharing it! Where did you get it?

Also, does it go higher than 90F? The data you shared appears to suggest that higher temp does speed replication while maintaining very similar L/Y ratios as with cold activity. I understand lactic acid bacteria (LAB) replication rates begin to drop after 91-92F. 

I guess my point is that for establishing a new starter, wouldn't we want the highest LAB and yeast activity we could achieve, to ensure that there are enough of both to establish a strong culture and outcompete any undesirable/nasty bacteria? IIRC yeasts prefer a neutral or acidic environment in which to grow, so by that measure starting out creating more LABs, and then bringing down the heat will acidify the environment to let yeast replication thrive. And as far as yeast replication goes, ~80F is the optimum temp (still much warmer than room temp for most people). 



dabrownman's picture

a Fresh Lofian Doc.Dough who took Ganzle's raw data on sourdough cultures of Labs and Yeast and built the spread sheet. There was another row for 93 F.  As you can see the yeast and labs reproductive rates fall off, the yeast more so,  over 91 F. but the 13 for the Lab to yeast ration is as high as it gets so 93 F final proof will give you a very sour bread and since the yeast reproductive rates fall off it will take longer to proof too which means more sour as well. 

Since you are trying to start both yeast and labs with a new starter the best temperature to establish one is 82 F which is the best for yeast but not bad for labs either.  Once established it is best to store starters in the fridge  for more sour and on the counter 68F-72F for the least amount of sour.  You also don't want to retard the dough or levain nor do a high temperature final proof (85 -90F) if you don't want sour.

There is some data out there that shows the labs may be supplying half the CO2 to raise the bread too! This would change the way we look a t SD cultures where we though yeast supplied the CO2  and the labs supplied the the acid for sour. 


     93 340.6569461690.6709831480.050047283



chris319's picture
Reproduction Rates of Labs and Yeast 
T(°F)T (°C)L. SF IL. SF IIYeastL/Y Ratio
36° F2° C0.0190.0160.0053.787
46° F8° C0.0470.0430.0212.222
61° F16° C0.1440.150.1141.265
64° F18° C0.1870.1980.1631.145
68° F20° C0.2390.2590.2251.064
72° F22° C0.3010.3320.2951.021
75° F24° C0.3740.4160.3651.024
79° F26° C0.4530.5080.4141.094
82° F28° C0.5350.5980.4171.284
86° F30° C0.6090.6720.3461.76
90° F32° C0.6580.7060.2023.255
93° F34° C0.6570.6710.05013.127
cranbo's picture

Thanks for sharing this. 

So this does, at least in part, confirm in my mind that if you want to build a starter that is high in LABs then starting your starter at high temperatures is the best way to go; of course this means that initially, this will be to the detriment of your yeast production, but on the up site, the acidification of the culture should create a better environment for yeast replication at lower temps.

dabrownman's picture

chart for over a year to make more or less sour.  I think you want to establish the SD at 82 F so that the labs and yeast are balanced.  Once you get it going well, stiffen it up, cut the amount down and put it in the fridge for storage as well as retarding dough overnight, the bread will be plenty sour. IF you want more sour you can retard the levain too like I do.   Once the culture is going it is pretty easy to make it as sour as you want.

chris319's picture

Note that Larraburu Brothers bakery in San Francisco proofed at 105 F, while an unidentified S.F. sourdough bakery proofed at 86 F. If I were to pick a temperature it would be no higher than 90 F due to the rapid fall-off of yeast production at 93 F.

cranbo's picture

Interesting. Makes sense that high temp proofing would have its place in certain baking schedules. Here again I wonder if these high temps help build that greater level of sour flavor (both examples you provided were for sourdough, weren't they?)

chris319's picture

Yes, sourdough. That was the only kind of bread these bakeries made. Back in the day, Larraburu was considered the gold standard.

When making the starter or "sponge", Larraburu fermented the sponge for 9 - 10 hours at 80 degrees F. The competing bakery let it ferment for 7 - 8 hours at 80 degrees F. Keep in mind that a portion of the previous day's sponge was used as an inoculum for each day's sponge. It's not as if they were making a new starter from scratch.

Here are the proofing times and temps:

Larraburu -- 4 hours at 105 degrees F

Competing bakery: 8 hours at 86 degrees F

In my very limited experience, of the two I suspect the longer, lower-temperature proof will give the better sour, but I could be wrong.

Until just a few years ago, Pioneer made excellent-tasting sourdough when their bakery in Venice, CA was operational. The bakery is now located in Santa Ana. The way I read their ingredient list, and judging from the taste of their product, I suspect they now add bakers' yeast, meaning it is no longer a type-1 sourdough. The flavor just isn't there. It's really not worth spending your money on. Pioneer has a much softer crust than the old S.F. sourdoughs.

chris319's picture

I made starter and kept it in my "incubation environment" at approximately 30 degrees C (86 F), then made a loaf with my modified S.F. SD technique, and damn if it's not awfully darn close to the tangy flavor of the Larraburu I grew up with. It has the tanginess which I imagine is supplied by the L.SanFran. Previous efforts have turned out plenty yeasty-tasting but with not enough tanginess.

My incubation environment consists of a 40-watt incandescent light bulb in a lamp holder with a spring clip and reflector and a conventional thermometer. No thermostat or switch, just a light bulb on all the time.

I still have to work out some hydration issues with the dough before I have a presentable loaf. My modified technique is to mix flour, water and starter, omitting the salt, and proofing for 10 or so hours, then add the salt and kneading.

My favorite starter flour is now KA first clear.

cranbo's picture

Thanks for testing it out chris319! 

Yep, I agree that when done exactly, this results in a very tangy starter. 

chris319's picture

I think I need to improve my very primitive incubation setup with better temperature control. I've ordered one of those yogurt-maker thermostats which should arrive any day now. It has some kind of thermal sensor which I could possibly stick right in the dough and measure the actual dough temperature rather than the temperature of the surrounding air.

My problem was that with a really long proofing time, the dough was turning to goo. I think I've cured this by dissolving the recipe's salt in water which just happens to be 31 degrees C, accomplishing two things: the salt gets dissolved and dispersed throughout the dough, and the warm water pre-warms the dough. The salt inhibits the proteolysis which turns the dough to goo. But I don't think the dough is actually getting up to 31 C.

Cranbo, was that your video I saw on youtube kneading dough in a KitchenAid and doing the window-pane test? It has a lovely musical bed. I modified the stock C-shaped dough hook on my KA after some experimentation and it's been working really well. I need to compose a post describing it.

chris319's picture

I am now using the DIY yogurt maker thermostat and it keeps the dough temperature exactly at 31 C, right where I want it. It is perfect for this application.

I've tried various proofing times but get the best results with a 12-hour proof. This seems kind of long to me, having read the manufacturing process used by Larraburu and a competing bakery. I'd like to get this proofing time down but the results are less satisfactory at less than 12 hours, even when the dough temperature is 41 C, the temp used by Larraburu for a 4-hour proof.

cranbo's picture

Yes this sounds about right, it's designed for a fairly long proof period. Haven't played around with it lately. That's always the trade off: how much (perceptible) flavor are you willing to sacrifice in order to accomodate a different production cycle. 

Good to hear the yogurt maker thermostat is working well. Can you share more info about it? 

chris319's picture

I am looking into some of the proofing times used by bakeries in the bay area, but first I must determine whether a given bakery is making authentic S.F. sourdough. There is one that claims a 24-hour proofing period.

This makes reference to a 24-hour refrigeration period at the Boudin bakery. Doesn't say how long the warm proof is.

chris319's picture

I tried making a loaf with a 24-hour proof at 31 C. Disaster! At that temperature the dough is partially done after 24 hours and you don't get a good rise. The crumb is too dense and the flavor isn't very good. 12 hours seems to be the sweet spot, or close to it.

A long cold proof would probably be different.

morahb's picture


I'm on day 2 of this starter. It is only at 70° how do I make it warmer??

Also, do you have tips on how yo maintain my starter once its active? Ie do I feed it right when use it or when I want to use it next? Warm water or room temp? Thanks!

cranbo's picture

Hi morahb, 

Thanks for trying it out. 

I've compiled a list of tips to keep your sourdough starter warm here:

Before you use it, you want to feed it and wait until it peaks (doubles in volume), as described in the directions for Day 8-11. Then you can use it in your recipe.

The feeding method described in Day 4 will yield about 135g of usable starter, with a little bit remaining so you can maintain it. You may need to build it up to get the right amount of starter. For example, if your recipe needs 300g of starter, it's best to build up to it over a day or two. dabrownman has a nice table for how to calculate builds, see the 2nd table in forum post here: 

Once it can consistently double in volume in 4-6 hours, it's ready to use. You have to watch it to find out how soon it will peak; this can vary anywhere from 3 hours to 12 hours. 

Water temp should be warm 85-90F, as described in Day 4. 

morahb's picture

Thanks so much!!

One more thing, I'm on day 6 and my starter is very thick. It is like a thick dough, not pasty at all. Should I be adding more water or its OK?

cranbo's picture

Yes, it should be very thick; as long as there are no dry pieces in the dough, you should be fine. If there are unmoistened bits of flour, feel free to add 1 tbsp more of water.