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Mike's (more or less) Weekly Baking Tips Logo2021-02-28 A Deep(er) Dive Into Starter Maintenance

With a special look at feeding cycles and starter discard

Sometimes I wish I was a sourdough newbie all over again. Is it because I could again enjoy learning all about this wonderous process we all immerse ourselves in and revere? Well, yeah, there is that, but mostly I wish I could again be in that early stage where I thought I knew everything. Now when someone asks a question, I rarely have a clear cut answer. I waffle and start by saying something like, "It depends on what you want to do." Still, sometimes it seems that newbies are divided into two large groups (and a few smaller ones).

One large group is afraid of making a mistake and is looking for THE right way to do things. Bad news bread heads - there isn't ONE right way to do things! Also, you'll learn a lot more by experimenting and making a few batches of bad bread than you will if people tell you what to do. A bad batch of bread isn't a big deal. I don't think I've ever made a totally inedible batch of bread. Well, a few times I fell asleep and the bread burned, and one time my night baker didn't take my admonition to calibrate the thermometer seriously and she grievously under baked bread which cost us customers - they just didn't like goo oozing out their breads! Still, with most failed experiments, you can grind the bread into bread crumbs and season it, you can cube it and sell it as croutons or turn it into bread pudding. SO many options!

Another group thinks they know it all, any especially know the One True Way of doing things. In truth I spent some there, but had lots of baker friends who expanded my horizons and vision. (Or, brought me back down to Earth.) Fanaticism rarely survives contact with reality, but sometimes reality has to knock on your door really, really loudly for you to notice someone is at the door.

There are smaller groups of newbies and bakers who work hard to expand their horizons without being prodded.  I'm there - on my better days anyway - and I hope you will be there also.

Before we get into the real topic of this note, I'll share two thoughts. As Father Dominic, The Bread Monk, used to say, "It's only bread, it will forgive you!" Also, if you are happy with your bread, you're doing it right - no matter what someone on social media says.

What brings on this semi-philosophical opening? I've been getting lots of questions about feeding starters, hooch, and discarding starter lately. And everyone seems to think their way is the One True Way. In reality, a lot depends on what your goal is. We select our tools - and methods are tools - to meet our needs. As the old saying goes, "to a man with only a hammer, the whole world looks like a nail."

Today, the world wide trend is that we eat much less bread than we used to. This is true in the United States, France and Germany. Individual consumption was over 1 1/2 pounds per day in Germany and France, as bread was their main source of nutrition. In the late 1940's, Americans averaged about 5 slices of bread per day, which is small compared to Europe, but still more than today. Andrew Whitley in "Bread Matters"  commented that he knows of no industry that has so dramatically cheapened its product and then complained that consumers aren't buying it the way they used to. Yes, there are other headwinds facing bread, such as gluten issues and low carb diets, but a lot gets back to the fact commercial bread doesn't taste as good as it used to, and many people report digestive issues after eating commercial bread, even if they don't have gluten issues.

The reduction in bread consumption has an impact whether one is a home baker, a cottage food producer, a village baker or if one has a modest sized bakery. Somewhere on the site I joke about our romantic image of maw and the oldest daughter baking several times a day to keep themselves, paw, the other 12 kids, the ranch hands, the farm hands, the miners and the posse that drifted through fed. Baking is rarely a several time a day thing for households these days, or even for anyone that doesn't have at least a modest bakery.  Historically, most bread was risen with sourdough, so we made lots of sourdough starter and used it. And, I seriously think, that the starter was happier that way, in the way that working dogs that are bred to work hate not working, I think sourdough starter wants to make baked goods. Maybe attributing wants and desires to microscopic organisms is a bit too much anthropomorphism, but there we are. I'm in the middle of the scale here - I don't name my starters, but I do talk to them. However, I don't believe they answer me, so I'm not completely crazy (which is what someone who is completely crazy would say, isn't it?)

Another historical note. When reliable baker's yeast became available in the mid to late 1800's bakers abandoned sourdough in droves. Yeast didn't need to be fed at all hours of night and day and in the hands of inexperienced people yeast was much more reliable. As a result, much sourdough knowledge was lost. When sourdough began to become popular again in the 1970's or 80's, bakers had to relearn, to rediscover, how to handle sourdough. There were, to be sure, isolated pockets of sourdough admiration that had survived the great sourdough abandonment. San Francisco retained a lively sourdough culture throughout. Italy used, and uses, sourdough to make Pannetone among other breads. France uses sourdough to make levain breads. And Germany has had its own sourdough culture, more about that in a few minutes.

The most common sourdough maintenance protocol is to feed a retained culture flour and water. Biologists call this approach "back slopping". Catchy name, huh? In many biological cultures this would be a recipe for disaster with the culture changing and not retaining it's character.  However, the bacteria and yeast in a sourdough culture have many defense mechanisms to keep out unwanted organisms. How strong are these defenses? If you add bakers yeast to a healthy sourdough culture, the yeast will be gone in about two feedings. It just can't survive the acidity.  While some sourdough yeasts are the same type as bakers yeast, they are different strains. Off the shelf bakers yeast does not survive exposure to a sourdough culture.

Some of the key elements at work here are the feeding paradigm, the hydration of the starter, and how much the starter is fed. Each of these things has impacts on the starter, and are discussed in a tab below.

Feeding Paradigms

Let's look at what modest sized bakeries do first. When we visited Boudin Bakery in San Francisco they had a bus tub filled with a very dense starter, probably around 50% hydration, in a walk in cooler. It seemed they would use some of it every day to feed up for the next day's production. When the amount in the tub was sufficiently reduced, or when it lost vitality, they'd feed the starter in the tub until it was where they wanted it to be and then put it back in the walk in. My feeling was they had more than one such tub, so if anything happened to one tub, there were more to fall back upon. Of course, Boudin also has multiple locations, so if one location lost all their starter they could get some from another location. Having a backup is important!

This technique is consistent with what Dr. Sugihara, the researcher who discovered the characteristic microorganisms that make San Francisco sourdough work, did. He used a technique used by the San Francisco Sourdough Bakers in the 1960's and 1970's, maintaining the starter at 50% hydration and almost tripling the amount of starter with each feeding.

From what we have been able to determine a famous French bakery maintains their starters at about 76% hydration, which is quite thick, and feed their starters twice a day, each feeding being a blend of flours and enough to increase the size of the starter about 2 1/2 times.

Many bakeries prefer a more liquid starter, and make up enough each day so they can meet their production needs and have enough to feed for the next day's production. Let's imagine I need 80 kilograms of starter every day this week. If I am feeding the starter a 1:2:2 ratio three times a day, I need to have 3 kilograms at the end of the production cycle to feed up for the next day's bake. To 3.1 kilos of starter, I add 3.1 kilos each of flour and water, giving me 9.3 kilos of starter. 8 hours later, I feed that 9.3 kilos of starter with 9.3 kilos each of flour and water, giving me 27.9 kilos of starter. 8 hours later, I feed the 27.9 kilos of starter another 27.9 kilos of flour and water, giving me 83.7 kilos of starter. We could further fine tune the numbers.

French trained baker, Gerrard Rubaud, fed his starters four times a day, quadrupling the amount of starter with each feeding. He ground the bulk of the flour used to feed the starter with a hand cranked flour mill. He also feels of the starter ever gets below 50F/10C it is ruined and must be discarded. He also starts a fresh starter every 3 or 4 months because his starter becomes too acidic for him to tolerate.

Blaine Marvin, of the Elmore Mountain Bakery, keeps her starters at 100% hydration, feeds her starters twice a day, with each feeding doubling the size of the starter, until the last starter before baking which explodes the amount of starter. Her last feeding increases the starter by a factor of 20. Put another way, the starter before the feeding is 5% of the final starter amount. She feels this helps control the acidity of the starter, as well as increasing the yeast activity. In general, high feeding ratios tend to favor the yeast part of the starter symbiosis.  We talk about this in the Five Percent Solution blog post.

As mentioned, German bakers have done things differently. Instead of back slopping, a typical German baker gets a new pure sourdough culture from a biological laboratory every Friday. It is fed in a large temperature controlled tank with oxygenation and agitation all weekend long. On Monday, the culture has eaten through the nutrients in the tank and is all but dead. However, the starter is very acidic and very flavorful. It is used to acidify and flavor doughs, with baker's yeast added to raise the dough. Rye breads benefit from having an acidic dough, and sourdough acidifies the dough very effectively. The acidic starter is used all week long, and the process starts again on Friday. The German bakers keep their starter very liquid as they want the starter to be pumpable, so they can dispense it from hoses into the mixers. This style of sourdough horrifies many American sourdough hobbyists who don't want to use bakers yeast with sourdough, but the German bakers make excellent bread.  As a result of this practice, the Sourdough Library in Belgium is reluctant to accept starters from Germany as they want naturally occurring starters, not lab created ones.

The German Federal Centre for Cereal, Potato and Lipid Research which was located in Detmolder, Germany, wanted to help sourdough rye bakers and created a number of feeding paradigms to get a starter into shape to make rye bread quickly and efficiently. I've used these techniques to revive wheat starters as well as rye starters. The three stage process involves three carefully thought out feedings, each with precise amounts of flour and water added to a starter at a controlled temperature for a specific time. The final starter is at 94% hydration. With this process you can turn 60 grams of starter into 10,000 grams in three feedings over 2 days. Many rye bakers use the 2 and 3 stage versions of this process which are usually called the Detmolder 2 stage and Detmolder 3 stage processes.  I talked about the Detmolder 3 stage process in a blog post. (Of course I did.)

Recently, some younger German artisan bakers have moved back to the more historic sourdough handling using back slopping, such as is seen in the United States.

If you are curious about these different feeding paradigms, our sourdough feedup spreadsheet will help you use them. Just check our downloads area, or skip straight to the spreadsheet download here.

Home bakers have historically had similar methods for propagating and maintaining a starter. Many pioneers put their starter into their barrel of flour which tended to maintain a fairly uniform temperature. This is similar to the Desem starter process.

Again, as with modest sized bakeries, larger homes and homesteads maintained fairly large amounts of starter because they were baking often. Biscuits, pancakes, or waffles in the morning, bread or rolls for lunch, and more bread for dinner. Sourdough was also used to leaven cakes.  When used and fed regularly by a skilled baker, starters remained healthy.

And that brings us to the modern home. Family sizes are smaller than historically, and often several people don't want to eat bread at all. Baking daily is just not an option in all but the most fresh bread obsessive family. Bread lasts longer than just a day.  For most families, baking every day means giving away or selling bread or freezing it. If you freeze it, you are only delaying the problem as you will run out of freezer space in short order.

And that brings to the starting point of this post. What do you do with your starter?

When I got into sourdough in the late 1990's, many people felt you had to feed your starter regularly to keep it happy. Like twice a day. If you double the size of the starter each time you feed it, which is a very small feeding ratio, you have a problem in very short order. Starting with a teaspoon of starter, doubling twice a day leads to a swimming pool full in 10 days. And two swimming pools full with the next feeding - and a very irate neighbor. Something has to be done to keep the amount of starter manageable. And that something is to discard half the starter before each feeding. So, instead of accumulating a swimming pool of starter (which is one heck of a waste of flour), you discard 50 to 100 grams of starter twice a day. Which is a much smaller waste of flour, like 50 to 100 grams a day.

We use the word "discard" rather loosely here. The discarded starter has food value. It has flour in it, as well as a lot of microorganisms. It behooves us to do SOMETHING with the discarded starter!  Discarded starter is quite acidic, so it can be used to raise quickbreads.  It can be used to make pasta - pasta made with sourdough discard lasts longer than pasta without.  A number of web sites have recipes to use sourdough discard, we're one of them.  Google can help you find more recipes for sourdough discard.  We like a number of these recipes enough that we often make excess starter just to make these recipes! I tend to think of the discarded starter as starter I've set aside for other uses.

Still, the discard half before feeding approach above is very useful for helping a starter mature. As you use a starter it gains in flavor and power for some time. Depending on who you talk to, 30 days and 90 days are common numbers. So, if you have a new starter, work it for a while at room temperature. Your bread will thank you.

However, there are better ways of handling sourdough starters if you want to limit how much discard you create. Refrigeration is the first step. When your starter is healthy (by which I mean, at least doubling in size between feedings), feed it one more time and put it into the fridge. I call this a storage starter. Dr. Sugihara found starters which were freshly fed survived freezing better than ones that had matured. I find the same is true of refrigerated starters. Some people want to see that their starter will rise before they refrigerate it. My view is, if it has been consistently rising after feeding, it will rise again. Interestingly enough, your starter will rise in the fridge. Slowly.

When you are getting near a bake day, look at your recipes to see how much starter you will need. Take enough starter out of the fridge so you can feed it up over three days to get the amount of starter you need. This insures the starter you use will be healthy. An old systems analyst mantra has it that "it takes a consistent process to create a consistent product". The consistent process starts with a consistent starter.  Pro-tip - the spreadsheet mentioned above will help you calculate how to create the amount of starter you need.

If you are baking commercially, consistency is very important. If you tell people this is your Colorado High Mountain Whole Wheat Bread, your regular customers will have an expectation of what the bread will be, and will let you know if it doesn't measure up. At home, having a good loaf of bread is often good enough even if it isn't just the same as last time. If you are in the "good enough is good enough" camp, you can use a storage starter fresh from the fridge if it's been there less than a week.  I won't be very judgy.

When you run low on storage starter in the fridge, or when you think your storage starter isn't as healthy as it was, you can pull some out, feed it up, and put it into a fresh jar. The old jar can be kept as a backup, until the next time you feed up your storage starter.

If you are making a storage starter at 100%, or higher, hydration, you may find it throws off hooch and loses vitality fairly quickly. I like to re-feed such a storage starter once a month or so. A hooch layer is a good hint that your starter is weakening, as is the starter taking longer to revive than usual.

And that brings us to my last technique for dealing with storage starters. Instead of storing it at 100% hydration, I store it at 50% hydration. When I use it, I feed up a few grams of it to the amount I need for a bake, so the fact it isn't at the same hydration as my usual starters just doesn't matter as the original storage starter hydration is overwhelmed in the feeding process. I've had these starters in the fridge for a year with no problems. If you check out our spreadsheets, you'll see there are spreadsheets that make feeding specific amounts of starter easy.

Starter Hydration

We've observed many times that if you ask 4 sourdough bakers for advice, you'll get at least 6 answers. This is another of those areas, there are ongoing arguments about the ratio of flour and water in a starter, or the starter hydration.  This talk excites many people who know the One True Way.  We'll talk about what different bakers do and the consequences of this.

Many beginners use a cup of water and a cup of flour. We can argue about cups and consistency, but it is what it is. Based on typical cup usage, that makes for a very wet starter, at around 160% hydration, or with more water than flour. This leads to a very active starter, one which will go through the flour very quickly. With a starter like this, frequent feedings are recommended. When this starter burns through its food, it will throw off hooch. Hooch is a dark liquid in or on your starterHooch is a more or less clear liquid that forms on top of, or sometimes as a layer in, sourdough starter. It is made up of water and alcohol. Hooch is a slang term for low grade alcoholic beverages. I sometimes wonder if the California or Alaska sourdoughs got desperate enough for some booze to drink their hooch. More seriously, hooch is a sign that you haven't fed your starter enough, or frequently enough.

More experienced bakers tend to weigh their ingredients, and they also weigh the starter feedings. My recipes, or formulas, call for starter at 100% hydration, or equal parts of flour and water. This works well, and doesn't throw off hooch very quickly. Feeding a starter twice a day effectively prevents hooch from forming.

In some cases, bakers use lower hydration starters. Dr. Sugihara used 50% hydration, and some French bakeries use around 76% hydration. These low hydration starters are difficult to mix, but last a long time without needing to be fed. In a refrigerator, they can last and remain healthy for months, and often for a year.

There are ongoing discussions about the impact of the hydration of the starter on the final bread. Some bakers insist that a very liquid starter is needed to make a sour bread. Others insist that it takes a stiff starter to make a truly sour bread. However, when bakers have tested the results, it seems that the hydration of the starter has little impact, by itself, on the sourness of bread.

Feeding Ratios

Feeding ratios are the ratio between the starter you are feeding, the water you are adding, and the flour you are adding.

It is usually represented as 3 numbers with colons between them. So, if the number is 1:1:1, that means 1 part of starter, 1 part of flour and 1 part of water. 1:2:2 means 1 part of starter, 2 parts of flour and 2 parts of water.  When the last two numbers are the same, this indicates the starter is at 100% hydration.  While this is common, it is not required.

If you are feeding at 50% hydration the numbers might be 1:2:1 or 1 part starter, 2 parts flour and 1 part water.

Does the first number have to be a 1? No, it's just been that way in these examples. One of my preferred feeding ratios is 2:1:1. This is enough to double the size of the starter each time it is fed.

What is the practical difference between the feeding ratios? Mostly, it's a matter of how long it takes the starter to reach a peak, usually when it doubles in size. Sune, the foodgeek, on YouTube experimented with a number of ratios. All of the starters reached the same peak, about doubling in size. However, how long it took to get there varied. He put together a time lapse video that shows the results.

We find that our 2:1:1 feeding doubles in about 4 hours. A more extreme 1:10:10 feeding might take 8 to 12 hours. However, this will vary based on your starter, and its health. The only way to tell is to experiment. You can see a 1:2:2 starter time lapse we created to the right. Let's watch a starter rise and fallThe video also demonstrates a few things of note. After feeding, nothing happens for a while. We call this the lag phase. It's like you after Thanksgiving dinner - you just want to sit down and digest the meal. Then the starter rises for quite a while. Then the rise stops and holds steady for a while, followed by a decline in the height of the starter. We used an Android app, FrameLapse, to create the video. There are other apps that will do the same, but this one was easy to use and did the job for us.

One effect of more extreme ratios is that the initial feeding will greatly dilute the acidity of the starter. However, in the long run, it will work out about the same.

Different Strokes

In the "Feeding Paradigms" tab we talked about what seems, to me, to be the most common ways handling sourdough starter.  Of course, "most common" may not be synonymous with "best".  Some of the methods I'll describe below leave me gobsmacked.  It isn't clear that they would work for anyone, but I suspect an underlying element is that a guided natural selection has occurred, so the microorganisms that can survive these unusual treatments survived.  If Darwin were alive and a microbiologist, he'd be fascinated!  In the "Feeding Paradigms" page I talk about the importance of consistency for some bakers, and how for others a good loaf is good enough, even if it isn't the same as last time.  Which is to say, I have no idea how consistent a product these different approaches produce.

A number of the stories below are from emails people have sent me.  Some people really don't want their name splashed around some web site, and I understand that.  To help them maintain their anonymity, I am only using their first names.  If you are one of these people and you have issues, please let me know.  I can delete the story, I can change your first name in the narrative, I can change your name to your whole name, I can include your email address so you can get more spam - whatever you want, just let me know.  In this case, I am cheap and easy!

I have more baking books than the law should allow, and while I remember stories I don't always remember where I read them.  If someone can tell me which book this comes from, I'll update this, give you credit for your excellent memory, and give you a free printed copy of whichever of our cookbooks you'd like.  So, the story...

The cookbook author and baker was in the bakery when a neighborhood woman came in and asked if she could buy some flour.  She baked her traditional bread and had run out of flour.  The baker talked with her and after hearing her method, he gave her the flour in exchange for a loaf of her bread.  She made a sourdough bread, but didn't maintain a culture.  She made her bread in the same dough trough every time, and the bread always rose.  She never washed the trough, just scraped it clean.  It seems enough microorganisms survived each cycle to raise her dough and replenish the dough trough.

John wrote:

I was interested to read your email on sourdough starters. My own starter regime is even more extreme. 
I keep mine in a jam jar in the fridge and I never feed it. When I am going to bake the next day I take out a tablespoon of starter the evening before and mix it with enough 50% flour and water in a large
preserving jar to produce enough leven for the recipe. This happens about every two to three weeks. When the fridge starter is nearly gone I start a new jar using the rinsings from the preserving jar (after a bake)
and 50% flour and water, and put it straight in the fridge. My starter has been going like this for more than 10 years and the bread always rises just fine. Each jar of starter must live in the fridge, unfed,
for a couple of months before it gets depleted enough to need restarting. I don't know if this regime would work with any starter culture but it is extremely low maintenance. I
don't have any starter to discard and I don't need to remember to feed it. When I bake, I usually make
three loaves and freeze most of it. I live alone and I have not bought bread for many years.

And then Rosemary wrote:

All I can say is you have a “spoiled child starter”
I have been negligent to the extreme with mine to say the least and it’s just bubbling and saying “thank you for my food” constantly

Rosemary had promised a picture of her starter, but it seems the Internet gods were hungry and ate her starter

Dick wrote, back in early 2020,

Many years ago I started my starter by putting a bowl with a flour and water mixture and covered with cheese cloth n my deck for a couple of days and was delighted to find activity. I had been baking bread semi commercially so I immediately started using my sourdough. Of course, over the first few months it changed in character quite a bit but proved to be reliable and unfussy. That was probably 20 years ago. On baking day, about monthly, I take the starter out of the fridge at breakfast time, start expanding it at noon and bring it up to about 1100 gm at bedtime. After leaving it out all night I start the bread dough the next morning and bake it by late afternoon. Occasionally I leave it in the cellar (in winter) overnight. Shaping the loaves and baking occurs after the dough has risen. It's not very sour but the bread has good flavor and crumb.

Probably 15 years ago my wife and I took a two month trip across the country and back. Shortly after our return I did some adding or flour and water and discarding of part for several days. And then it was back to its old activity. I do not feed it between bakings, just lazy I guess. I wouldn't mind if it were more sour but I'll take it as it is, old reliable.

Dennis offered a bit more of a take:

One of the guys on "Breadtopia's Forum" uses only a teaspoon of old starter from the cooler (he bakes once every 2 weeks) in his levains and his bread is absolutely beautiful.  BUT, the levain can sit for many hours (days) until it is ready according to him.  But he is like me when it is ready we bake, we don't have to get out the bread for the morning customers.  Frankly I eat way too much bread now and my waist line is starting to show it so its good it is taking longer.   I'll probably have to eat my hat one of these days with what I do but then no calories in the hat................................LOL
I think the bottom line to this conversation is this.  If you want starter that is rea dy to go NOW then it needs to be fed every day.  If a person is willing to let it do its thing for a few days until it is ready then there are other options.  

5 thoughts on “2021-02-28 A deep dive into feeding sourdough and discard -Mike’s (more or less) Weekly Baking Tips”

  1. This is excellent! I’ve gotten fairly obsessed with sourdough and my main weekly bake is bagels. I keep a fairly small amount of starter in the fridge; take it out and feed it/scale up for the 225g I’ll need for a bagel batch, then send it back into hibernation.

    I keep a quart of discard/backup starter in the back if the fridge to make pancakes or crackers.

    It’s been an easy routine and I don’t worry all that much about the starter. I figure if prospectors could manage to keep their starter alive without food scales and refrigeration, I can manage. 🙂

    Love your newsletter. Happy baking!

  2. Love your blogs and have learned so much. I’ve been making sourdough for a few years now and have been experimenting with types of flour I feed (rye, whole wheat or bread flour) ratios and on occasion hydration. This Deep Dive was especially interesting and timely. I do keep my starter and a jar of discard in the refrigerator at all times until a couple days before bake day when I start to feed. Recently started keeping a notebook so I could see what difference the changes make and notice they all turn out great looking and tasting loaves of bread and the tastes are just minor differences but could also be due to the difference flour I’m using in the actual dough or the length of time I do a retard. Bottom line is that I no longer stress over what ratio, flour or hydration level I use in the starter because there doesn’t seem to be a wrong way, just a different way. Thanks so much for your blogs and the class I took from you. Just bake is my motto!

    1. Hi Sally,
      Thanks for the kind words!

      I like your bottom line – don’t stress! As Father Dom said, “It’s only bread, it will forgive you!


  3. Thomas Cappiello

    there’s a lot of bewilderment out there in the bread/baking/sourdough world, as I’m sure there are in many ambitions. Speaking of foolish questions I recently read on Facebook about someone complaining about a pancake recipe that made her pancakes too thin, and asked how to make them thicker. SMH. It takes a Village, and I suppose patience (and calm) is a virture.

    1. Hi Thomas,

      Oh yeah! I think that is a great example of someone who is afraid to experiment and wants to know the One True Way. One of my (many) mottos is “when it doubt, try it out.” The worst thing that can happen is you make a batch of bad bread, or pancakes you don’t like. If you can afford a computer and Internet access, hat’s hardly the end of the world!


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