So I am just beginning on my bread making adventures and have been studying the concept of water to flour proportions for baking bread.

My question is about experimenting with other types of ingredients (e.g. replacing water with milk, etc.) and how to determine if what I'm doing is scientifically correct.

Should any ingredient that I add that is liquidy (I think I made up a word there) be calculated into the water % target?

So, if I start with a basic bread recipe that calls for 65% hydration and I decide I want to use water, eggs and sour cream do I weigh the eggs and sour cream and deduct their weight from what would have been the water weight at 65% hydration?

Starting recipe:

  • 1kg of Flour
  • 650ml water

New recipe with experimental ingredients substituting in as part of the hydration calculations:

  • 1kg of flour
  • 200g of egg
  • 150g of sour cream
  • 300ml water

Is this the correct approach when experimenting? Or, am I missing something key (e.g. sour cream's hydration is likely not equal to water's on a gram for gram basis, etc.). I'm looking for some guidance on how to best approach experimenting with recipes so that the experiments are at least based on sound bread making principles (rather than complete WAGs).

Thanks for any help or guidance!

  • Welcome to the site, and good question! It also may not matter quite as much as you think - if you effectively replace a few percent of water with fat, the newly added fat may have a more significant effect on your bread than the removed water.
    – Cascabel
    Commented Mar 28, 2013 at 21:09
  • I agree. While I have tried to answer your question in the spirit it was intended, I would go with the first order approximation (assume highly liquid ingredients are pretty much 100% water) unless you discover a need for greater accuracy.
    – SAJ14SAJ
    Commented Mar 28, 2013 at 21:15

1 Answer 1


It depends on how exact you feel you need to be.

Rough Approximation

As a general first order approximation, the following ingredients can all be treated essentially as water:

  • Milk, butter milk
  • Fruit juice
  • Fruit puree
  • Milk, cream, sour cream, creme fraiche and similar dairy products
  • Even eggs

This is not perfectly accurate, of course, but for many applications it is close enough.

If you want to get more detailed and more accurate, you would have to find out a reasonable approximation what percentage, by weight, is actually water.


For dairy products, like cream, this is fairly simple to do, as a second order approximation. Just deduct the percentage of fat and assume the rest is water. For example, whipping cream which is 36% fat (check the label) is going to be about 64% water. This is still an approximation as it does not consider sugars and minerals, but it is probably close enough for almost any non-industrial culinary use.

According to the IDFA (International Dairy Foods Association), sour cream is about 18% milk fat, so an approximation of 80% water would be quite reasonable.


The University of Illinois provides the following information about eggs:

  • Whole eggs—74% water
  • Whites—88% water
  • Yolks—48% water


This PDF from the U. of Kentucky Extension provides composition information, including water percentage, for some common fruits. Most, with the notable exception of bananas, are in the mid-80 to mid-90% range. Bananas are about 75% water.

Other ingredients

For other ingredients, you would need to do some research to determine the typical percentage of water.

Example Calculation

Based on the following recipe (from your original question), using second order approximations, we conclude:

1kg of flour
200g of egg         --  74% water, so 148 g water
150g of sour cream  --  80% water, so 120 g water
300ml water         -- 100% water, so 300 g water         
                                      568 g water

So this version of the recipe has a bakers percentage of about 57% hydration. This is a little lower than your original recipe.

In truth, this may not matter so much as a starting point, because you would adjust the dough by feel as well as hydration percentage.

Other effects

While hydration percentage is an important contributing factor to the quality of your loaves, remember, any time you add ingredients other than the basic four (flour, salt, water, yeast), the additional content of the ingredients are going to affect the structure, texture, crust, rise, and flavor of your final product.

Sugars, fats, and eggs will all significantly change the loaf, both by affecting the gluten development, and by influencing how the yeast grows.

  • Thank you so much! This is exactly what I was looking for and gave me additional insight into how to experiment with my bread!
    – Zigrivers
    Commented Mar 30, 2013 at 12:47

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