Why the brix of milk decreased when temp decrease? I wanna make a milk lactose free but when I decreased temp from 70 C to 12 C, the brix of milk will decrease. Moreover, after fermentation the milk with enzyme lactase, the brix of this milk is very decrease (decrease around 5 brix).
So, please help me why the brix be like that?? Thank you.

it is the most commonly accepted one

answer: semi-infinite solid initially at a uniform temperature of 400 ◦c is cooled at its surface by convection. the cooling fluid at a constant temperature of 200 ◦c has a convective coefficient (ha) of 250 w/m2.k. the physical properties of the solid: k = 20 w/m.k and α = 4 * 10-5  m2/s. using δx = 0.04 m and δt = 10 s. write the finite difference equations describing the transient heat transfer of the first five δx and the temperature profile after 30 s.