February 4, 2011 - 1:55pm

## What is hydration?...

Hi everyone - I keep seeing the phrase 'hydration'. and I am quite mystified;-) can someone enlighten me as to what it means (water content/ratios??) and is the term different when used in the context of sourdough starters?

cheers!

Yes, hydration is the ratio by weight of water to flour. So a 60% hydration dough made in a batch with 1kg flour would contain 600g water. It is the most reliable way of relating a formula that is easy to scale up or down.

I believe it is used the same way with sourdough starters.

Hydration, when followed by a % sign indicates the quotient of the weight of the water divided by the overall weight of the flour.

Example. I have 10 grams of starter at 100% hydration. That means that I have 5 grams of flour and five grams of water (5/5=1 (100%). If I had 10 grams of starter at 10% hydration, I'd have 9 grams of flour and 1 gram of water.

The same concept applies to the overall recipe. If my recipe called for 100 grams of flour, 60 grams of water and 10 grams of starter at 100% hydration, my overall hydration would equal (60+5 of water)/(100+5 of flour)=0.619~ or 61.9% hydration.

Baker's math. Anybody else?

Wouldn't 9 g of flour to 1 g of water be 11% hydration? It's the proportion of liquid to flour, not the proportion of liquid to the whole. So 1/9 = 11% hydration (liquid over flour) not 1/10 (liquid over total weight)

Or am I wrong about that?

You are right.

"Better to remain silent and be thought a fool than to speak out and remove all doubt." Abraham Lincoln.

Words to live by in this internet age.

Oh I don't think it's worth a hair shirt, surely not, LOL! I hate to think how many times I've mispoken something like that, LOL!

The term "Hydration" refers to the percentage of water in a dough or starter as it relates to the flour. For example if you were mixing a starter and wanted to mix a 100% hydration, you would add equal amounts of flour and water to the old starter. Say 25 grams of old starter and 100g of water and 100g of flour.

The same applies to the dough calculations.

Eric

In the FAQ there is a glossry where Hydration is defined as follows:

Hydration: the ratio of liquid ingredients (primarily water) to flour in the dough. A dough with 500g of flour and 340g of water has a hydration of 68% (340/500).

The reason I point to it is to ensure that there is not any confusion caused by the prior discussion of starter or dough hydration - the entries use the term "water" where by definition it should be "liquid". For example, milk would be counted if a formula contained it, and if the same formula also contain water, then the milk and water would be ADDED together when determining the hydration.

This is confusing at time because many ingredients contain "some" liquid and some "solid" - for example honey. If you want to be absolutely correct in your hydration calculation one would take that portion of liquid into account also.

Ben

when discussing hydration. BakerBen is correct that there are some liquids, like milk, which have such high water contents that they should be added to the water in a formula when calculating hydration. And there are other liquids which contribute water, but should not be considered as water equivalents on a weight basis. These would include syrups such as honey, molasses, golden syrup, etc. If significant quantities are used in a formula, it's best to know how much water each brings to the party.

Then there are "solids" that also contribute an amount of water, albeit usually small. These would include butter, fruits, vegetables, etc.

And, finally, there are liquids which contribute no water whatsoever: oils. They should not be included in hydration calculations because they do not provide any water to wet the flour.

If you want to be precise, and accurate, understand that certain ingredients will affect the overall dough hydration and that their use may require you to adjust either the amount of flour or the amount of water as you make the bread.

Paul

Looks like I duplicated this post .... Sorry 'bout that.

Actually, the term "hydration" has nothing to do with percentages of water. For bread making, the "amount" or percentage of hydration is a ratio of water:flour but the term hydration outside of its influence to a bread formula simply means combining water or other liquids with something else; like the cells in your body when you drink a glass of water.

Thank you for all the helpful information - i'm still yet to apply the hydration math to my baking yet but I will be the next loaf I make;-) That reminds me - got to feed my starter!

V

Thanks for this helpful information.