Glossary

Grubdog asks

[quote]
Can you explain to me what you mean by the term hydration.
[/quote]

If you look up the link that Bill has posted above you will find

[quote]
hydration: Several meanings in this context: 1) The weight of water in a a leaven or a dough, relative to the weight of flour. Therefore, a dough at 70% hydration is 41% water, and a leaven at 100% hydration is 50% water. 2) The capacity of a flour to absorb water (usually called absorption). 3) The quantity of water in flour (related to environmental humidity).
[/quote]

In this forum, and most baking fora you will find home bakers using
'hydration' to refer to the first of these meanings.
It is a way of comparing bread dough recipes, since one of the important variables that determines how a dough behaves is how much water is in it.

Put simply, to calculate the 'hydration' of a dough, divide the total weight of water/liquid in a dough, by the total weight of flour in the dough.

To confuse things a little we sometimes talk about the 'hydration' of a starter. This is the same idea, just dividing the amount of water in the starter by the amount of flour.

An example:

My standard recipe uses
200g starter
500g flour
320g water
10g salt

The starter is at 100% hydration, so that means that it contains 100g water and 100g flour.

Total water = 320g + 100g (in starter) = 420g
Total flour = 500g plus 100g (in starter) = 600g

Hydration = 420/600 = 70% (multiply by 100% to get the percentage)

To give you a bit of a guide: doughs which have hydration of 50% make a very stiff dough, 60% make a firm kneadable dough, 70% a sticky dough, 80% an incredibly sticky unkneadable dough, 100% a thick batter

does that help?

cheers
Dom

Thanks Bill!