The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

How do things like oats affect hydration?

epchris's picture

How do things like oats affect hydration?

I have a recipe for a basic sandwich loaf that uses rolled oats that I'm trying to play around with, but to do some calculations I want to figure out what my starting hydration is.  If the recipe has about 3cups of flour and 1 cup of oats, how do I calculate the hydration?  I can weigh them at home (I'm not there right now, so I'm not sure how much the oats weigh), but I'm pretty sure I was using 15.5oz of flour and 10oz milk.

So if I've read other things correctly, should I be assuming milk is 90% water?  And if so, is my calculation: (10 * 0.9) / 15.5, or is it (10 * 0.9) / (15.5 + weight_of_oats)?  In other words, are the oats part of the "flour" part of the hydration calculation?  I would assume they represent the "dry" ingredients :)

Or am I way off? :)

doughboy82's picture

are done on total cereal weight.

Oats are a cereal and therefore your 3 cups of flour and 1 cup of oats is 4 cups of cereal.

unfortunately where im from we use metric weights so i have no idea what oz are into grams.

as a guess with a 25% oats i would consider about 60-65% water. 90%water is to high even for a ciabatta loaf, but i can understand how you worked the 90% out

epchris's picture

Sorry if I wasn't clear, but I read somewhere that milk should be counted as 90% water, so if you have 10oz of milk, you use 9oz as your number for calculating hydration.  I guess it doesn't matter too much.

Oats are 3.5oz/cup here, so my original numbers would be

3.5oz oats

15.5oz bread flour

10oz milk

52.6% hydration right? The dough was really dry, so I'm considering bumping up the milk so I get 63% hydration, or about 12oz milk.  Does that sound like my math is right?

hansjoakim's picture

I'm not sure if there's one correct way of doing it, but in the recipes I've seen, oats are usually not included when you calculate "total flour" of your dough. They're either listed as a standard ingredient, or put into a "soaker" part of the recipe.

Your recipe looks pretty dry, epchris. You could compare it to the straight oatbread recipe in "Bread". The flour, oat and liquid ingredients are:

  • Bread flour: 75%
  • Whole wheat flour: 25%
  • Rolled oats: 16.5%
  • Water: 62.5%
  • Milk: 11%

In addition, there are also 7.5% oil and 7.5% honey in the recipe that further increase hydration. Assuming milk to have 90% of water's hydrating capacity, this recipe is at least at 72.4% hydration (not counting oil and honey). You could try those figures, and work from there? The oatbread in "Bread" is very tasty.

epchris's picture

@hansjoakim: Thanks for the info, I didn't get around to trying modifying the recipe I have, but I'm first going to try for 62% hydration without taking the oats into the "dry" number and then with, and hopefully something will work out better.  I should try finding this oatbread recipe in Bread, but I don't have the book.