The ethanol is dehydrated to about 200 proof using a molecular sieve system and a denaturant such as gasoline is added to render the product undrinkable.
This technique has been used to measure equilibrium unfolding of the protein by measuring the change in this absorption as a function of denaturant concentration or temperature.
At temperatures or denaturant concentrations close to their apparent midpoints, proteins may switch from downhill to two-state folding, the "type 0" to "type 1" transition.
Another target gene may have greater variation in length, but the denaturant gradient uses a second element (of melting point) to further distinguish between the samples.