Water Content for Baking

Quick Start

Knowing the water content of the batter or dough is important for baking. Because eggs, butter/marge and even flour contain water, we need to calculate our percent water, to a good-enough approximation. We also, surprisingly, need the density. The values used in the calculations are listed below. The data are useful inputs to the Baking app


My thanks to my family, friends and neighbours who contributed useful suggestions for making this more useable.

Moisture for Baking

Flour g
Sugar g
Butter/Margarine g
Eggs g
Dried Fruit g
Nuts g
Oats g
Syrup/Honey g
Cheese g
Oil/Lard g
Salt g
Carrots/Parsnips g
Liquid g
% Liquid
Total g
Water g
Water %
Density g/cc
Diameter cm
Length cm
Width cm
Height cm
Volume cc
//One universal basic required here to get things going once loaded
window.onload = function () {
    //restoreDefaultValues(); //Un-comment this if you want to start with defaults

//Main() is hard wired as THE place to start calculating when inputs change
//It does no calculations itself, it merely sets them up, sends off variables, gets results and, if necessary, plots them.
function Main() {
    //Save settings every time you calculate, so they're always ready on a reload

    //Send all the inputs as a structured object
    const inputs = {
        Flour: sliders.SlideFlour.value,
        Oats: sliders.SlideOats.value,
        Sugar: sliders.SlideSugar.value,
        Syrup: sliders.SlideSyrup.value,
        Butter: sliders.SlideButter.value,
        Oil: sliders.SlideOil.value,
        DryFruit: sliders.SlideDryFruit.value,
        Nuts: sliders.SlideNuts.value,
        Eggs: sliders.SlideEggs.value,
        Salt: sliders.SlideSalt.value,
        Carrots: sliders.SlideCarrots.value,
        Cheese: sliders.SlideCheese.value,
        Liquid: sliders.SlideLiquid.value,
        PercLiquid: sliders.SlidePercLiquid.value / 100, //Convert to fraction
        D: sliders.SlideD.value,
        H: sliders.SlideH.value,
        L: sliders.SlideL.value,
        W: sliders.SlideW.value,
        isRound: document.getElementById('isRound').checked,

    const result = CalcIt(inputs);

    document.getElementById('Total').value = result.Total;
    document.getElementById('TotalW').value = result.TotalW;
    document.getElementById('Water').value = result.Water;
    document.getElementById('Density').value = result.Density;
    document.getElementById('Volume').value = result.Volume;

//Here's the app calculation
//The inputs are just the names provided - their order in the curly brackets is unimportant!
//By convention the input values are provided with the correct units within Main
function CalcIt({ Flour, Oats, Sugar, Syrup, Butter, Oil, DryFruit, Nuts, Eggs, Salt, Cheese, Carrots, Liquid, PercLiquid ,D,H,L,W,isRound}) {
    //This is inelegant code but it's easy
    const FlourPW = 0.13, OatsPW = 0.08, SugarPW = 0, SyrupPW = 0.22, ButterPW = 0.16, DryFruitPW = 0.20, NutsPW = 0.10, EggsPW = 0.75, CarrotsPW = 0.9, OilPW=0, CheesePW=0.35

    const Total = Flour + Oats + Sugar + Syrup + Butter + Oil + DryFruit + Nuts + Eggs + Salt + Cheese + Liquid
    const TotalW = Flour * FlourPW + Oats * OatsPW + Sugar * SugarPW + Syrup * SyrupPW + Butter * ButterPW + Oil * OilPW + DryFruit * DryFruitPW + Nuts * NutsPW + Eggs * EggsPW + Carrots * CarrotsPW + Salt + Cheese * CheesePW + Liquid * PercLiquid
    const Water = 100 * TotalW / Total
    const Volume=isRound?Math.PI*D*D/4*H:W*L*H
    const Density=Total/Volume

    return {
        Total: Total.toFixed(0) ,
        TotalW: TotalW.toFixed(0),
        Water: Water.toFixed(0),
        Density: Density.toFixed(2),
        Volume: Volume.toFixed(0),

Just slide the sliders to capture, to a good-enough extent, the weights of ingredients. The % moisture of each is listed below, though obviously there are plenty of variations so the numbers cannot be exact. From these you get the % water in your mix. This will, obviously, have a big effect on the baking process. Loss of water during baking is discussed below.

For eggs, assume a weight per egg of:

  • Europe: 43g, 53g, 63g and 73g for Small, Medium, Large and Extra Large.
  • USA: 43g, 50g, 57g, 64g and 71g for Small, Medium, Large, Extra Large and Jumbo.

For liquids such as water, milk or orange juice, enter the weight in g (or the volume in ml, they're close enough) added then the % of that liquid which is water, i.e. 100, 90, 88 for these examples. In the default recipe for a sponge cake there's a "dash of milk" which is conventionally 5g of this 90% liquid. If you have to add "juice of one lemon" that's 45ml and "juice of one orange" is 70ml.

For those who like chocolate, it's approximately 0% water so use the oil/lard slider.

If you are going to make substitutions, it's good to think about the impact on water concentration. For example, replacing sugar with the same amount of syrup, honey or agave would give you 20% less sugar and 20% more water. Substituting butter or margarine with oil or a fat like lard gives you 16% less water and, therefore 16% more fat.

Values used

  • Flour: 13%
  • Oats: 8%
  • Sugar: 0%
  • Syrup/Honey: 22%
  • Butter: 16%
  • Cheese: 35%
  • Oil/Lard: 0%
  • Eggs: 75%
  • Dried Fruit: 20%
  • Nuts: 10%
  • Salt: 0%
  • Carrots/Parsnips: 90%

Volume, weight and density

An aerated sponge batter of the same initial size as a heavy cake will cook much faster. That's because for a given rise in temperature, 2g of batter/dough needs twice as much heat as 1g and a heavy cake has a greater density, i.e. weight for the given volume in the tin. For the Baking app we therefore need to enter the density of the mix. As most cooks aren't familiar with the idea of density, you can calculate it in this app by entering the diameter of your tin (or length and width if you choose the Rectangle option) and height of batter/dough. The volume is then calculated, your total weight is already known so the density is calculated. Use this, plus the % water, in the Baking app.

Water lost in baking

If we under-cook then the result is a soggy mess. If we over-cook (but don't burn) the result is too dry. Water, as you will see in the Baking app has a big effect on the temperature inside the cake, and the app also reveals how much water is lost.

If the baking community knows (or measures) the weight of all the ingredients before baking then measures after baking then the reduction in weight is the water loss. What's an ideal water loss? We don't know. But the community could crowd-source a lot of data for typical types of baked goods and we could start to see how much (or little) water loss correlates with flavour and texture. If we also have good data on density (acquired with no real extra effort) then we will really be in a good place.