The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

What is the weight of a cup of 100% hydreation sourdough starter?

bmuir1616's picture
bmuir1616

What is the weight of a cup of 100% hydreation sourdough starter?

I am just a little bit dense here and confused at the same time. 

What is the weight of a cup of 100% hydration sourdough starter?  240 grams?  300 grams? 

Please help!

Thanks,

Bill

Pablo's picture
Pablo

Depends on the activity of the yeasties, Bill.  If they've been working hard and there's lots of CO2, then it would be lighter than if it were just mixed up.  It's nothing that can be definitely nailed down, I don't think.  That's why things are specified by weight, because volume is not reliable, especially in this case, where you have an arbitrary amount of gas in the volume.

Why, I wonder, do you want to know the weight of a cup of starter?

:-Paul

bmuir1616's picture
bmuir1616

Paul:  Thanks for the response.  And, you are right.  Depends.  But, the reason I ask is because a lot of recipes I run into (some in well known books like Beth Hensperger's The Bread Bible and some on the Internet) call for 1 cup of starter (no weight given). 

And, if you want to play around and increase the starter to say 1-1/2 cups, how do you do that if you do not have a starting point for the weight of the cup of starter? 

Rose Levy Beeranbaum in her book, The Bread Bible, says that a "scant" cup of liquid (100% hydration) starter weighs 240 grams.

Peter Reinhart in his The Bread Baker's Apprentice says that a cup of his "seed" starter (88% hydration) wieghs 7 ounces or 198 grams.  

And, lastly Jeffery Hamelman's Bread: A Baker's Book of Techniques and Recipes recipe for Vermont Sourdough says that two tablespoons of liquid (100% hydration) weighs 1 ounce.  So 16 Tablespoons in a cup means that this cup weights 8 ounces or 226 grams.  

So, who's right.  Or is it as you say, "It depends..."

To keep things easy, I'm going to say that a cup of liquid starter (100% hydration) weighs 230 grams (that's an average between Rose and Jeff).  

 Thus, based on this weight, a cup of liquid starter would contain 115 grams of flour and 115 grams of water.  

It's a place from which to start. 

:) Bill

Pablo's picture
Pablo

Sounds good.  You might also try weighing a cup of your starter...

:-Paul

Mike Avery's picture
Mike Avery

I weighed it a while ago, and it's 280 grams for my starters.

 

As to starter varying depending on how active they are, in the interest of consistent volumetric measurement you should stir down the starter before measuring it.

 

Mike

 

phxdog's picture
phxdog

OK, I admit that I'm as dense as a loaf of poorly made whole wheat bread but would there be much if any difference in weight of active vs inactive starter?

Volumn sure, but CO2 gas is not going to give any lifting effect like say, helium, would it? And if it did, would any of the scales we all use pick up such a small difference in weight? I'll bet if I weigh an empty balloon, then blow it up to 3X it's empty volumn, my scale would not regisrter the added CO2 & moisture. And are'nt the little beasties CONVERTNG the existing weight of sugars to CO2? Not ADDING new weight?

I'm giving myself a headache.

Scott.

Pablo's picture
Pablo

 Hey Scott,

It's weight per volume.  No, the starter isn't going to float away.  Imagine egg whites.  How much volume do six egg whites take up?  What is their weight?  Now whip them and ask the same two questions - different volume/weight ratio in your answers, eh?.  If your initial question was "how much does a cup of egg white weigh?" then, in order to answer it, you would have to know if they were whiped or not.  Same with the starter.  If you're asking "how much does a cup of starter weigh?" you need to know how gaseous that starter is in order for the answer to be meaningful.

-Paul

phxdog's picture
phxdog

Thanks Paul.

Your egg white example brought it into clarity and makes me wonder why I did not grasp the concept right away (must be getting old!).

Now this begs the question; should you always 'stir-down' a starter before measuring it by volumn?

Scott.

Pablo's picture
Pablo

Mike's the man to listen to on that, and he says:

 "As to starter varying depending on how active they are, in the interest of consistent volumetric measurement you should stir down the starter before measuring it."

:-Paul