# Calculating Evaporation Rate for Milk

So, I am kind of physics dumb. I have found the equation for water evaporation from a pool and I have been attempting to make work and make sense for creating a spreadsheet that will help me predict the amount of water evaporation from milk while cooking it in order to create a reduction.

My question has 2 parts in that sense: How do i figure out the rate of evaporation of water for milk (I really need help breaking this down)?

And

How can I put it into a spread sheet where I can easily edit it as the variables change?

Right now, my variables are as follows: constant temperature for milk of 71°C, controlled room temperature of 70°F, and a pot of 30cm diameter.

As of right now, the humidity is very different from day to day (does higher humidity mean less evaporation?) and I have no way of calculating velocity of my kitchen air, however I am thinking of adding a fan in order to increase evaporation rate.

Is that enough information to have someone help me answer my question? I would really appreciate a break down of the math so that I can put it into a spread sheet for future use.

Thanks, Aric

• really, it's quite impossible to compute this evaporation from scratch. But you can measure the weight of the pot and deduce a solution for you exact experimental / production context. – user46925 Aug 23 '15 at 10:31

The problem you face is this: water is a homogeneous collection of one type of molecule. Milk is a heterogeneous collection of hundreds of different molecules, some of them quite large. Now, any given molecule, if in a homogeneous assembly, has a measurable partial pressure, which defines (roughly) the evaporation rate. However, once you mix molecules, even as simply as, say water and $NaCl$ , there are interaction effects which change the evaporation rate for each specie.