Why are some bricks fired in brick kilns red and some blue?

The firing methods of green bricks and red bricks are different. Red bricks are fired in large brick kilns, while green bricks are fired in small brick kilns. When the kiln is closed, water is used to seal it on top. Use water for cooling. Red brick kilns are called dry kiln bricks, which do not use water for cooling. They rely on the temperature difference from the outside to cool the bricks in the kiln. Both types of bricks are good, it just depends on the needs. For example, if some places want to build the style of ancient buildings, they choose green bricks.