Correct use of brake fluids

Brake fluid is the medium which conveys the pressure from the brake lever to the brake pad and is attached to the frame or the fork. The master cylinder presses the brake pads on the disc towards each other and the bicycle brakes. There are two kinds of brake fluids currently in use: DOT or mineral oil.
Mineral oil has the advantage of being non-toxic and it does not absorb water so quickly. DOT, however, guarantees a more powerful contact point and also has a higher boiling point. In addition, the seals on DOT brakes wear down less quickly than on others.

DOT stands for the American Department of Transportation, which classifies brake fluids as follows:

DOT 3: Boiling point at around 205 °C, dyed yellow
DOT 4: Boiling point at around 230 °C, dyed yellow
DOT 5.1: Boiling point at around 260 °C, dyed yellow
Mineral oil: Boiling point at around 190° C

The brake fluid should be replaced once a year.