How does the ingredient converter work?
Ingredient conversion works differently depending on what units you are converting between.
There are three basic cases to consider:
- Converting between different units of weight
- Converting between different units of volume
- Converting between weight and volume
All three cases are outlined below.
If you would like to know the ratios for all the units of weight found in the converter you may explore the
Converting between different units of volume
Similar to units of weights, units of volume are also related to each other by a simple ratio. For example, one
liter is about 4.227 US cups.
If you would like to know the ratios for all the units of volume found in the converter you may explore the
volumes table.
Converting between weight and volume
Conversion between weight and volume is a bit more involved as there is not a simple ratio that can convert
between units of weight and volume. We must instead know the density of the ingredient we wish to convert.
The density, typically denoted by the greek letter ρ (rho), is defined as mass divided by volume. This can be
expressed as an equation: ρ = m / V. Weight, in the context of cooking, is the same as mass*.
Using the equation, we can calculate the mass as m = ρ · V, and volume as V = m / ρ. Just like weight and
volume, density has to be expressed in units, for examples grams per milliliter or g/ml.
Say that we want to convert 1kg of all purpose flour into US cups. Assume that we know the density of flour is
0.53 g/ml. First we convert 1kg into 1000g. Using the formula we see that V = 1000g / (0.53 g/ml) which gives us
1886.792... ml. From our table of volumes we see that 1 ml is roughly 0.00423 US cups. 1886.792 · 0.00423 ≈
7.98.
All that work just to find out that 1kg of all purpose flour is 7.98 US cups. Luckily the converter will do this
automatically for you if you just pick the units and quantity.
What if you want to convert volume to weight? Say 1 US cup of flour to kg? We use our volumes table to find out
that 1 US cup is roughly 236.588 ml. The equation gives us that m = (0.53 g/ml) · 236.588, that is 125.392
grams. Multiplying by 1000 as per our weights table and rounding the results gives us 0.125kg.
If you would like to know the densities for all the ingredients found in the converter you may explore the
ingredients table.
(*In physics, weight denotes the force of gravity acting upon an object and is
calculated by multiplying the mass by the graviational acceleration. However, in cooking we use weight to
simply refer to mass. For more information please checkout
wikipedia.)