The Fresh Loaf

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What is the difference between a starter at 100% or 166% hydration

coffeetester's picture

What is the difference between a starter at 100% or 166% hydration

I am currently making my first starter ( I liked his method since it was primarily geared at a flour and water. I chose to do by mass and not by volume. I  have been measuring out 1/4 of a cup of filtered water into a pyrex container and then zeroing my scale on this. I then measure out King Arthur Whole wheat flower tell the weights are equal (Tonight I want to measure how much flower I am actually using). While looking threw most of the blogs I keep seeing starter at 100% and 166%. My starter is pretty thick and all the posts keep saying pour out 1/2 of the starter. My starter is more like a sticky dough. I actually have to use my spatula to cut out 1/2 of the starter to re-feed. So after that background here are some of my questions:


Did I make a 100% or 166% hydration starter?

Can I split the starter in a couple of days and make a White Bread, Rye and/or Wheat starter? Do people keep different kinds of starter around or do you use the same base and change the flour you bake with?

Can I convert the starter between the 100% and 166%? Can this be done when you split off a portion of starter to make a loaf of bread?


PS on a side note did I pick a good way to start a starter (I know opinions vary). I just wanted to start the process and see what happens. Even if the starter does not develop by this weekend I am planning on baking a loaf of bread (no knead in a dutch oven).

wassisname's picture

 ...but only two answers!  100% and Yes.

If the weight of water is equal to the weight of flour your hydration is 100%.  The weight of water divided by the weight of flour gets you the percentage.

Everything else is pretty much up to you.  It will mostly come down to what kind of bread you like to bake.

Example:  I keep a 75% hydration, whole wheat starter.  Because (surprise, surprise) I mostly bake whole wheat breads and  I like my final doughs to be around 75% hydration.  Having the same hydration makes the math easier and using the same flour just makes sense.  It's easy enough to change the hydration if I want to build a piece of starter for a particular bread.  Likewise, if I'm making rye or white(er) bread I simply pull off a piece of my starter and feed it with the appropriate flour.  Just figure out what works best for you and have fun with your new starter!


BakerBen's picture


One simple question - from reading your post it is not totally clear the steps you are going through to weigh your water and flour.  are you doing the following:

- place the pyrex cup on your scale

- ZERO OUT the weight of the cup

- measure 1/4 cup water and place in the pyrex cup on your scale and note weight - should be approximately 2 oz - is it ?

- zero out the scale and add 2 oz of flour

Once you did this you waited until you saw some "bubles" - life in the starter ?  At that point you repeated the steps above with the result being that you now have the original 4 oz of water and flour and an additional 4 ounces of water and flour?  You wait again until the 8 oz bubles and may be even rises - at least 12 hours.

Note, that the 8 ounces in the pyrex cup are composed of 4 ounces of flour and 4 ounces of water - this is what is termed a 100 % hydration mix based on Baker's Percentage.  Now you are ready to start feeding the starter ... you do the following:

- stir the mixture to make sure all is combined. 

- pour off half the mixture in the pyrex cup - 4 ounces - half the mixture

- add two ounces water and stir well

- add two ounces flour and stir well ... the mixture is back at 8 ounces and still contain the same amount of water and flour so it is a 100 % hydration or what is called a 2:1:1 ratio 2 starter: 1 water : 1 flour mixture which is what the writer recommends to keep the starter at. 

> did I make a 100% or 166% hydration starter

   a 100% hydration starter

> can I split the starter in a couple of days and make a White bread, Rye bread and/or Wheat bread starter?

Recall, from the sourdough URL that you should continue feeding - 4 to 6 times or so - this starter and then transition it to unbleached white flour.  The white flour feedings will let the starter stablize nd get healthy - smelling like sourdough and doubling in size within 4 to 6 hours.  Once this occurs you can thing about spliting it to form other flour type starter.  You would transition to a different flour type (e.g. rye) just like you went from whole wheat to white flour.

> Do people keep different types of starter around or you use the same base and change the flour you bake with?

You could do either - it really comes down to how pure you want to be (e.g. if you say a loaf is 100% sourdough wholewheat then you would not want to use a white flour starter but a WW starter).

> Can I convert a 100% to a 166% ?

Yes, agin it is the ratios of water and flour that determine the final hydration of the starter.  Somewhere on TFL site there is a spredsheet to help you do this - I am sure you can find it.

> Can this be done when you split off a portion of starter to make a loaf of bread?

I am not exactly sure what you are asking?  Normally, one might take the portion of the starter that would be thrown away at a feeding and use it as the base for the starter at the new hydration.  You would feed it and let it "get healthy" prior to actually using it as the leavener to bake with.

Hope this helps. 



coffeetester's picture

Thanks for both responses. I think I understand. So I have a 2:1:1 starter cause i measured out .5 lbs and .25 water and .25 water and mixed well. As for bubbles I had them in my starter this morning with is 2.5 days later and some growth. I moved today to a new twist on Rubber maid disposable twist on top. This gives me a much better idea of how much growth I will get. I did see a picture reading in the forum where they used a rubber band to mark the current level of the starter. I will go home and do the same.


As for measuring. I pour 1/4 a cup of water in pyrex #1 and zero the scale. I then place empty pyrex #2 on the scale and add whole wheat flour tell the scale reads 0.000 lbs.


I am convinced now that I need to get a new scale that measure grams. My 0.005 LB scale just is not accurate enough for baking.


Thanks for the advice on multiple starters. I think I will stick with 1. I will switch to all white flour in 2 days. When I divide the starter for starting a loaf I will feed it twice with what flour I will use (White is first loaf and Rye is second).


PS Thanks for the good feed back.

G-man's picture

When working with small adjustments, grams are the way to go. The scale I have measures down to either 0.05 oz or 1 gram. I learned pretty early on that 1 gram is a bit more accurate, 0.05 oz being equivalent to about 1.4g, so I never use ounces anymore if I can help it. The more accurate the scale the better.

On multiple starters: One is good for a while, but somehow they tend to multiply if you let them. Be sure to check your population a few months from now.

Daisy_A's picture

Hi Coffeetaster,

Glad to hear you got into baking with starters. 

I started a culture back in January and stabilized it for a few weeks before baking. I couldn't make head nor tail of hydration at the start until I had read a few posts on TFL and info. in books. Feels odd because now it seems more like second nature!

Here are a few responses I hope are helpful.  My apologies if you know any of this already!

- Difference 100% and 166% starters:

As I understand it, starter hydration is measured by the ratio of water to flour. So a 100% starter would have 100g (ml) of water for every 100g of flour, whereas a 166% starter would have 166% of water for every 100g of flour and so on.  A 166% starter would be more liquid than 100%, although 100% is quite liquid so if you have to cut yours with a spatula I would recheck your measures.

You suggest getting a scale that weighs grams. This does make working out hydration in starters and formulae much easier, given that 1 ml is also 1g.

Do people keep different starters or make different bases from the same one?

They do both! Some bakers will keep both wheat and rye starters, say a 75% wheat starter for multigrain breads and a 100% rye starter for rye breads. Other bakers keep just one starter then take a part off to build up a new culture on the bench.  If bakers keep just one starter to use with different grains in baking then it is often rye, because of its stability and vigour. 

Can you split off a piece of starter to build a starter with a new hydration? Yes - I do this all the time now. However any change to hydration is a bit of a change for the yeasts too so I would feed such a starter 2-3 times at least on the bench (often over 2-3 days), before baking with it.

I have to note, though that my starters could not support much change well when young. You seem to have made the decision to work on building the starter that you have at one hydration for a while to strengthen it and this seems a good one, although you may have to feed it more as it gains strength!

Wishing you continued happy baking! Kind regards, Daisy_A 


coffeetester's picture

So I am now on Day 3. The good news is I came home and it looked like my starter had climbed the walls of my container and fallen. It was still 50% bigger then this morning. There where some nice bubbles and a nice (nice for SD starter but not in life) stench. The only issue is getting 50% of the mass out of the container. My starter seems to be very thick. Is it bad to add just a little extra water to it? Most of the starters I see here have a higher hydration level then the one I started with. Just looking for a little information to expand my curiosity.

coffeetester's picture

This mornings starter was really stinky. But it did not rise at all. I fed it. Should I be feeding a starter that is not rising or should I be feeding it more?

pmccool's picture

That behavior is normal in a young starter.  There's a lot going on in there even though it appears to be dormant.  In another few days you can expect to see more reliable and regular activity.


G-man's picture

If it smells cheesy or like turpentine, your starter probably has a leuconostoc infection. This should not alarm you, it happens all the time with water and flour starters before the yeast and good bacteria get established.

If you are truly alarmed by this, you can try this solution posted by Debra Wink using pineapple juice:

The infection will clear up in a day or two, tops, if you continue with regular feedings.

Your starter will go through a lot of stages of not rising, rising a little bit, rising a lot and then dying for a day or two, etc before it is finally established. It took my starter about two weeks to get going well, and at about a month of regular feedings (with breaks in the fridge) it had established a relatively predictable pattern of behavior.

Stay patient. This is untamed nature, after all. It won't behave like domesticated yeast in a can. Hehe.

Maverick's picture

You have received a lot of good advice above. I am a little late to the party, but I just wanted to add that one of the reasons you see a lot of 166% hydration starters is because that is approximately what you get if you use equal parts flour and water by VOLUME. So if you take a 1 cup measurement of water, that is 8 oz. If you then add a 1 cup measurement of flour, that is about 5 oz. 8/5 x 100% = 160%. If you use grams (which is more precise), then on average this is closer to 166%.

That said, the weight of a volume of the flour can vary a lot. In addition, different types of flour will show an even greater difference in weights by volume.

One more thing in terms of thickness of the starter. One of the reasons that your 100% hydration might look different than someone else's is because of the type of flour used (and humidity of your environment). If you mix a 100% hydration whole wheat starter, it will absorb a lot more water and be thicker than one make with basic A/P flour. Even brands of flour can make a difference.