Starter Maintenance

There are two popular methods of maintaining a sourdough starter: 1) the countertop method, and 2) the refrigerator method. 

Countertop Maintenance

With the countertop maintenance method, bakers keep their sourdough starter at room temperature and feed it at least once day. The countertop method generates a lot of discard, and is best suited for people who bake frequently (i.e., daily or multiple times per week). 

Refrigerator Maintenance

The refrigerator maintenance method typically requires weekly (or less frequent) feedings of your starter.  This method is best suited for people who bake infrequently (i.e., once a week or less) and this method generates less discard. 

Feeding Ratios

Starter feeding ratios are expressed as a series of three numbers, such as 1:1:1.  The ratio is the amount of retained starter, the amount of flour and the amount of water.  

A 1:1:1 feeding would consist of equal parts, by weight, of existing starter, flour and water.  A 1:2:2 feeding ratio would consist of one part existing starter, two parts flour and two parts water.  For example, if you have 30g of existing starter, you would feed it 60g of flour and 60g of flour. 

The most common feeding ratios for daily maintenance are 1:1:1 or 1:2:2. Your feeding ratio should provide enough food for your starter to make it to the next feeding, without starving.  

You can keep a very small amount of retained starter.  Some people keep as little as 5-10 grams as their carry-over amount. 

Why do I need to “discard?”

When you feed your sourdough starter, the yeast and lactic acid bacteria consume starches and sugars in the flour, and they create byproducts (alcohol and acid) in your starter.  These byproducts choke off the yeast and make it difficult for the yeast to reproduce or create carbon dioxide. 

If you are keeping your starter at room temperature, it will generally rise and fall in that time period, and when it falls, it is time to discard and re-feed (usually once a day).  You need to discard a portion of the starter to make room for fresh flour and water so the yeast can continue propogating.  

Discarding and re-feeding is just like cleaning an aquarium if you want healthy fish.  You need to periodically clean it out to keep the fish healthy because over time they are swimming in their own waste.  The same thing happens each day with a sourdough starter.  

You can make equally good bread with either method.  You should consider 1) how frequently you bake, 2) how much time you want to spend maintaining your starter, and 3) how much discard you can tolerate.  

Infrequent bakers should keep their starter in the refrigerator but be aware that when you plan to bake it helps to take your starter out and feed it a few times, at least one day before you plan to bake.  You can use a starter directly from the refrigerator, but the results are less predictable than a “refreshed” starter coming out of the refrigerator. 

The strength of a sourdough starter coming out of the refrigerator also depends on when it was last fed and how long it was in the refrigerator.  

For example, if you feed your starter 1:1:1 on Monday and take it out of the refrigerator on Tuesday, it will still be fairly diluted from the prior day feed and may be a little weaker (by volume).  If your starter was last fed one or two weeks ago, it will actually be quite strong coming out of the refrigerator.  It has consumed all of its food and the population is near peak.  If your starter has been in the refrigerator for more than two weeks and/or it is covered with hooch, this means it has depleted its food source, is starving, and is starting to lose some of its yeast population. 

A healthy starter has a low pH (high acidity) which preserves it at room temperature and creates a hostile environment for other bacteria and pathogens. 

It is similar to the way fermented foods keep from spoiling without refrigeration.  Your starter creates its own “vinegar bath” which keeps it from spoiling.  

For basic maintenance, your starter feeding ratio needs to be sufficient to provide enough food for your starter to make it to the next feeding without starving.  If you feed your starter a 1:1:1 ratio and the starter rises, falls and is completely starving (covered with hooch) before the next feeding, then you should increase the feeding ratio to 1:2:2.  Inspect your starter 24 hours after a 1:2:2 feeding.  If it is starving, then increase to 1:3:3, etc. 

In Chad Robertson’s Tartine Bread, he recommends a starter feeding ratio of 1:2:2 for daily maintenance. I generally follow 1:2:2 or 1:1:1 feeding ratios based on the season.  In winter, my starter can make it 24 hours with a 1:1:1 feeding.  In the summer, it moves more quickly so I increase my feeding ratio to 1:2:2. 

This is the simple rule for basic maintenance. When preparing your starter for baking, or when making a leaven, it may make sense to use a different feeding ratio.  This is covered in on the FAQ page “Starter Preparation.”  

Flour – The most common flour blend for starter maintenance is a 50/50 mix of bread flour and whole wheat flour.  You can use a higher percentage of whole wheat flour, but you generally do not want to use a lower percentage.  

It is possible to keep a starter alive by feeding it almost any type of flour, but for best results, stick with a primary diet of at least 50% whole wheat flour.   You can use all-purpose flour or bread flour for the other 50%. 

High protein flours, like bread flour, produce more gluten, but the gluten content is not necessary for maintaining a starter.  All of the gluten is deteriorated between feedings.  Your starter is simply using the flour as a source of sugar.  Don’t waste money on expensive or exotic flours for feeding your starter.  Find a basic flour that produces good results and stick with it. 

Some people feed their starters rye flour or a small percentage of rye flour (e.g., 10-20%).  Adding rye to your starter can sometimes strengthen it.  This is discussed in more detail on the “Starter Strengthening” FAQ page. 

Water – Always feed your starter unchlorinated water.  If your water contains chlorine, most household water filters will de-chlorinate it.  If your water contains “chloramine” (a different type of chlorine), some household filters will not remove this.  You can use bottled water, but filtered tap water is a more economical and sustainable option.  Distilled water is not recommended because it is stripped of minerals which could be beneficial to your starter. 

Yes.  You will not kill your starter by feeding it a different type of flour.  Some starters will take a few days (or up to one week) to adapt to a new type of flour.  It is fairly easy and common to switch among different types of wheat flours (e.g., whole wheat, bread flour, all purpose, einkorn).  However, if you try to move away from wheat flours, for example to create a gluten-free starter, I recommend following a specific recipe for creating a gluten-free starter.   

The hydration level of your starter is calculated by dividing the water content of your starter by the flour content. If you are feeding your starter equal parts flour and water, then the hydration percentage is 100% hydration.  The most common hydration percentage is 100%.  And you will find many recipes assume 100% starter hydration if the actual hydration percentage is not known.  

If you feed your starter twice as much water as flour, the hydration percentage would be 200% (this would be a very wet, liquid starter).  If you feed your starter half the amount of water as flour, this would be a 50% hydration starter — a very stiff starter. 

Yes. You should always feed your starter based on weight, not volume. When starter recipes call for “equal parts starter, flour and water,” some people make the mistake of using cups (or milliliters) instead of grams.  Equal parts in cups (a volume-based measure) will produce a very wet starter because a cup of water weighs more than a cup of flour.  You will need a digital scale for breadmaking, so make the investment in an inexpensive kitchen scale. 

Once you develop experience feeding your starter by weighing the ingredients, you will fairly quickly be able to “eyeball” the quantities and will not need to measure every day.  

You will not kill your starter by feeding it incorrect feeding ratios.  But for best results, feed equal parts flour and water, by weight. 

I use a one-pint (500ml) wide-mouthed glass canning jar with a plastic screw-on lid.  You want to use a vessel that is large enough to feed it and vigorously stir it while keeping the flour, water and starter in the jar.  Also, you want to use a vessel where the neck is as large, or larger than the side of the vessel.  If you use a vessel with a narrow neck, it is impossible to keep it clean and tidy.  

Always scrape down the inside walls of your starter jar after mixing, and wipe the rim. 

If you use a plastic vessel, you should use a food-safe plastic jar with a lid that can fit loosely or tightly.  An empty food container is a good option.  Many people find Talenti Gelato jars to be the perfect shape and size for starter maintenance. 

If you keep your starter in a glass jar, always keep a backup of your starter in the event that you drop your jar and shatter the glass.  A broken starter jar is an unrecoverable tragedy that you do not want to experience. 

You only need to keep a very small amount of starter to be able to propagate it or bulk it up for baking. For daily maintenance, I keep about 90g of starter, that is, 30g retained starter, 30g flour and 30g water.  Check out the “Scraping Methods” video below for an example of how to keep a very small quantity and feed it very infrequently.

If you are feeding your starter a 1:1:1 ratio (equal parts starter, flour and water, by weight), your starter should be the consistency of a fairly thick batter when fed.  Immediately after feeding, I can turn my starter jar upside down for a few seconds and the starter will not pour out. 

However, after your starter has risen and fallen it will be very thin — more like the consistency of paint — and it will be pourable.  This is very normal. 

You can see these examples in the video, “How to Maintain a Sourdough Starter,” below. 

This really depends on how messy your jar gets.  You do not need to put your starter in a clean vessel every time you feed it.  But you also do not want a lot of old dried starter building up on the rim or sides of the vessel.  Use your judgement. 

I keep my starter jar very clean by scraping down the sides and wiping the rim every time I feed it, so I transfer it to a clean jar once every few weeks.  If you keep a very messy starter jar you may want to transfer it to a clean jar more frequently.  

The only thing that can really kill your starter is mold.  A healthy starter in a clean jar will naturally resist mold growth.  If you have semi-dried starter on the sides of your vessel, this is usually where mold can get a foothold and ruin your starter. 

Your starter vessel should have a lid that can either be tight or loose fitting.  If you are keeping your starter on the countertop, you want to always keep it loosely covered.  If you do not keep it covered, you can get fruit flies or other undesirables in your starter.  However, you generally do not want your starter to be sealed airtight (on the countertop).  Many of the microbes can function anaerobically (without oxygen) but generally perform better with some air entering and exiting the vessel. 

If you keep your starter in the refrigerator, you want to seal it tightly so that it does not take on odors of flavors from other foods.  You do not need to worry about your starter jar exploding in your refrigerator. 

Some people believe you need to leave your starter uncovered to attract yeast and bacteria into your starter.  When you first create your starter, all the yeast and bacteria you need is already found in trace quantities in your flour.  There is no need to expose a starter to airborne microbes. 

Some people use clasp-top jars with silicone rings.  These have the benefit of sealing the jar tightly while allowing carbon dioxide to off-gas as it builds up pressure.  These are very commonly used for fermented foods but are not required for sourdough starter.  They can be used, but you’ll find they are very difficult to keep clean.   I do not recommend them. 

For basic maintenance, (using the countertop method), you want to try to find a feeding ratio and temperature that will support a once-a-day feeding.  If your starter is rising and falling too quickly, try a higher feeding ratio or try lowering your starter temperature.  The starter temperature has a much greater impact on rise time than the feeding ratio. 

If you are unable to find a ratio and temperature (for example, if you live in the tropics) that support a once-a-day feedings, you may need to feed your starter twice a day to keep it from starving between feedings. 

Some recipes and guides will recommend feeding your starter multiple times per day when preparing for baking.  This is a separate topic and is covered on the FAQ page “Starter Preparation.”  Multiple daily feedings are rarely required for basic starter maintenance. 

The easiest way to do this is to weigh your empty vessel and record the weight of the jar (I write the weight, in grams, on a piece of tape on the bottom of each jar).  For example, assume you’ve weighed your jar, empty without the lid, and it weighs 300 grams.  

If you are keeping a 1:1:1 feeding ratio of 30g retained starter, 30g flour and 30g water, then you need to remove all but 30g of the existing starter.  Begin removing starter from the jar and weigh the jar until it weighs 330g.   This means you have 30g of starter left in your 300g jar. 

You will find over time that you can approximate some of these measurements as you develop a rapport with your starter.  You will have a good feel for how much starter should remain, and you will be able to add flour and water without measuring it.  After about one month of daily measurements, I became very comfortable (and accurate) at eyeballing the measurements.  

That being said, it is important to measure your quantities from time to time if you are not measuring daily.  The amount of retained starter in the jar is deceiving.  It always looks like less starter than what is actually there.  So, you can begin to underfeed your starter by eyeballing the retained amount.  Periodically check your work. 

You need to discard to remove the “spent” flour from your starter and to make room for the next feeding.  If you did not discard any starter, your feeding ratio would increase exponentially.  For example, on day 1, you would feed it a ratio of 30g retained starter, 30g flour, and 30g water.  On day 2, without discarding, you would need to feed it 90 grams of flour and 90 grams of water (to maintain the 1:1:1 feeding ratio).  On day 3, without discarding you, would need to feed it 270 grams of flour and 270 grams of water. 

You can see that in just a few days your starter quantity would become unmanageable. 

There are many popular “no discard” methods.  See the video below, “The Scrapings Method,” for one popular example.  

No.  Not even close.  Fermentation is an exponential process so unfortunately basic arithmetic formulas don’t work when estimating rise times.  A 1:2:2 feeding only takes about 15% longer than 1:1:1 to peak.  

If you wanted to double your rise/peak time by changing the feeding ratio, you would need to do a 1:20:20 feeding.  

It is much easier to control the rise time of your starter and dough by controlling the temperature rather than the feeding ratio.  A change of 15F/8C in temperature will double or halve the rise/peak time of your starter or dough. 

When you see recipes calling for a 1:5:5 or 1:10:10 feeding, these are usually methods of creating a leaven prior to baking.  This is quite different from routine daily maintenance.  This topic is covered on the FAQ page “Starter Preparation.” 

Good question.  First, add up the sum of the parts in your feeding ratio.  If you want to feed 1:2:2 then the total parts in this ratio are 5 (i.e., 1+2+2=5).  Simply divide your target total quantity by the parts to arrive at the value of one part.  100g total target quantity divided by 5 parts is 20g per part.  

In this example, the feeding quantities would be 20g retained starter (1 part), 40g flour (2 parts) and 40g water (2 parts). 

Do some research and learn to identify the difference between mold and kahm yeast.  If your starter has mold in the jar or on the starter, you need to throw it away and start over again (always keep a dehydrated backup of your starter for this reason!) 

If your starter has kahm yeast on the surface, this is undesirable, but you can usually  salvage your starter by scraping off the yeast, scooping out a spoonful of good starter and restarting it in a clean vessel. 

A thin layer of clear liquid on top of your starter can either be water separation or alcohol (also known as “hooch”). 

Both water and alcohol can look the same. The easiest way to know if it is water separation or hooch is a simple test.  

• If the starter has not risen and fallen, it is usually water separation. 
• If the starter has risen and fallen and there are no bubbles left on top, it is usually hooch.  

Hooch, or ethyl alcohol, forms on top of the starter when it has depleted its food source and is starting to starve. 

If you leave a starter unfed for a very long time, the hooch on the top will also turn a dark gray color.  A dark liquid on top of your starter is always hooch, not water separation.  Hooch is commonly found on starters that have been neglected for some time.  It will also smell unmistakably like alcohol. 

There are different schools of thought on this question. I’ll tell you what I do. 

If the hooch is a thin, clear layer, I stir it in.  If it is a thicker, dark gray, boozy smelling layer, I pour it off. The thick, gray layer usually occurs when a starter is left for a very long time without feeding (e.g., months in the refrigerator).

Some people stir it in, regardless of the amount and color, believing that it improves the flavor.  This is a matter of personal preference.  

If you do pour off the hooch, be aware that you are changing the hydration level of the starter and you may want to compensate for this with a little wetter mix in the next feeding. 

If you are generating a lot of sourdough discard, first ask yourself if you can reduce your starter and feeding quantities so you are generating less discard. 

When I began baking, I kept 150g of starter and fed it 50g flour and water each day.  I reduced this to 90g total starter each day. 

With this method, I am now discarding 30g of flour each day.  This method consumes a 5-pound (2 kg) bag of flour about every 75-80 days.  I can live with that, so I dump my discard into my garden compost.  I also like the idea of releasing some of the starter microbes into the wild, as recognition for the service of their relatives who die a fiery death in the oven. 

If you are generating a lot of discard and want to use it, there are hundreds of sourdough discard recipes on the internet.  I particularly like sourdough discard cracker recipes. 

The Scrapings Method was popularized on the “Bake With Jack” channel on YouTube.  It is a creative and popular method of keeping a very small amount of starter in the refrigerator and generating virtually no discard.  

Check it out in the Videos section below. 

The best way to slow down your starter is to reduce the temperature.  If you are keeping it on your countertop and it’s rising too fast, try to find a cooler spot in your home (e.g., on a windowsill in the winter).  

You can also slow down the rise by increasing the feeding ratio, but this is difficult.  If your starter is peaking after a 1:1:1 feeding in 4 hours, you need to go up to a 1:20:20 feeding just to double that time to 8 hours.   Feeding ratios are not a great way to massively slow down your starter. They are for fine-tuning.  

Put Your Starter on Ice

If my kitchen is very warm and I’m trying to slow down my starter, I place my starter jar in a bowl of ice on the countertop immediately after feeding the starter.  This method essentially delays the start of the fermentation until the ice melts and the starter comes up to room temperature.  Depending on how much ice you use, this can delay the start of fermentation by up to 8 hours.  

There are some implications to putting your starter through wide temperature swings every day.  Different types of bacteria thrive at different temperatures.  The cooler temperature will favor the acetic acid and the warmer temperature will favor the lactic acid.  Cooling and warming your starter every day will build more biodiversity in your bacteria population, which could be good. 

Soak your jar, totally submerged, in a bowl of cool water (with or without dish soap) for 4-6 hours.  The crusty material will liquify and you can easily remove it. 

Feed it, put it in your refrigerator, and enjoy your vacation. 

If you leave your starter in the refrigerator for a week or longer, you may see a clear liquid forming on top.  This is “hooch” or alcohol.  It is a byproduct of the fermentation process. 

It commonly appears on top of refrigerated starters when they begin to run out of food.  

When I see hooch on top of my starter, I typically pour it off (rather than stirring it in), and if the top of the starter is gray (not moldy!), I scrape off the gray layer on top to reveal the creamy good stuff below. 

Then you have the a few options for refeeding.  If my starter has “gone hoochy,” I scoop out 10g of the creamy good stuff, transfer it to a clean jar and feed it 25g of flour and 25g of water.  This will refresh your starter.  Sometimes it will take a few feedings to come back to full strength, depending on how long your starter has been unattended in the refrigerator.