How much liquid (hydration) does your gluten free bread dough need? The simple answer is gluten free bread dough needs more hydration than wheat dough (or any dough with gluten).
There are of course several factors that determine how much hydration is optimal. For example, a gluten free baguette will not need the same hydration as a gluten free sandwich loaf. The final structure and feel of the crumb and to a lesser extent the type of crust determines how the bread dough should be prepared.
Hydration percentages also differ depending on the type of gluten free flour that is used. As a comparison, bean flours like garbanzo are "stickier", holding on to moisture more than rice or oat flour. Furthermore gluten free sourdough bread has it's own very distinct set of rules/processes.
I'll be focusing here on the amount of hydration needed to make a good gluten free sandwich loaf. Please note that while my recipes do not use eggs or butter, these ingredients also count toward the overall hydration percentage of gluten free bread dough.
How to calculate Hydration Percentage
Hydration Percentage of a recipe = Weight of the liquid x 100
Weight of the flour
To calculate the hydration percentage of your recipe, weigh the flour and all of the liquid ingredients
Divide the weight of the liquids by the weight of the flour and then multiply the result by 100
For example, a recipe containing 420g of liquids and 350g of flour your hydration percentage is 120% (420/350 x 100 = 120%)
If you know the amount of flour in your recipe and want to calculate the amount of water you need, multiply the weight of the flour by the hydration percent.
For example, a recipe containing 350g of flour, 120% hydration is 420g of liquid (350 x 120% = 420)
How much liquid (hydration) to use when baking gluten free bread
I have found that gluten free sandwich loaf dough that is properly hydrated looks more like a cake batter and cannot be kneaded or shaped. To that end, the best hydration for a soft flexible gluten free sandwich loaf is over 100%. Ideal hydration usually between 120% - 130%. Less than that will result in a dense crumb and a heavy loaf (see my video below).
However, for this to work there are 2 conditions that must be met:
The bread flour blend should have a decent protein and fiber profile
The baking tin must have tall sides
I have a post discussing "How to write a Gluten Free Bread flour blend recipe" and why protein is an important part of that formula. For now having a blend that has more protein than starch e.g. more buckwheat vs rice flour, gives more structure to the loaf. Extra protein and fiber contributes to an increase in loaf volume and crumb softness as well as improved texture, flavor, and overall appeal.
Regardless and even with the addition of non gluten forming structural proteins, this "hyper hydrated" state creates a fragile dough structure. This situation is aided but still not completely corrected with the introduction of binders like xanthan gum or psyllium husk (eggs can further improve the structural integrity of the dough).
We are accustomed to seeing regular bread dough that rises above the rim of the baking tin to create the classic dome of a sandwich loaf. Using a "normal" baking tin at a height somewhere around 2", it is highly inadvisable to let gluten free bread dough rise above the edge of the tin. In this state once the bread begins to bake the dough will collapse, resulting again in a dense loaf.
On the other hand a baking tin with tall sides will support the dough as it bakes. It is this combination, a properly hydrated dough AND a tall sided baking tin (4"+) that gives you the best result, a loaf with a nice rise and a very soft, open crumb.
Using a tall sided tin is one of the easiest things you can do to improve your gluten free bread. I share more bread baking tips and techniques as well as a troubleshooting guide in these blog posts:
This video shows the correct consistency for properly hydrated gluten free sandwich loaf dough. Note that the mix is more like a batter.
How can you tell if you used enough liquid?
Many bakers have a poke test to check proved (proofed) dough for readiness. My little test works when your dough is in the tin. I devised this test by chance as I was trying to sort out a tunneling issue (really big hole in my crumb).
If you poke your dough after it has risen (in the tin) and it shrinks or collapses it could be over proofed BUT more than likely it is not properly hydrated. I have tested this many, many times and the result is consistent, too little water and the dough shrinks, enough water and the dough does not move. The dough also keeps the height during and after baking, I am always rewarded with a beautiful, airy loaf! (see my video below) What do you do if your dough shrinks as you poke test it? You could remix the dough with a bit more water and allow it to rise again. OR you could bake the bread as is and the next time you bake adjust your recipe. Add a little more liquid and take notes until you figure how much hydration is enough.
Remember it is not just one thing that will give you success when making gluten free bread. The right flour blend, proper hydration, a tall sided baking tin (see my other tips) all work together to give you the best result.
This video demonstrates how I do my "poke" test. Notice that the height of the dough remains the same before and after baking