CHEMISTRY BEHIND THE PROCESS
If cold brew coffee is using the same materials such as water and coffee when brewing it hot, how can it really taste that different?
As much as which type of roasted beans you use and how it is ground impacts the final taste of your coffee, the way that it’s brewed can have actually have the biggest impact.
When coffee beans and water mix, there are a lot of chemical reactions taking place in order for your wonderful cup of coffee to get made. These reactions help to pull solubles from the grounds – which in turn gives the coffee it’s familiar taste and smell.
These solubles dissolve best between 195 to 205 degrees F – so coffee brewed with hot water pulls these chemicals out of the grounds quickly. They also evaporate easier, giving you that sweet smelling aroma from a fresh pot of hot coffee.
Having increased solubility isn’t always good. The boiling water forces the chemical compounds of the coffee to oxidize and degrade. This is why hot coffee is known to have a sour and bitter taste.