Knife skills is one of the main reasons I enrolled into culinary school along with wanting to learn and understand the who, what where why, and why's behind food, new techniques and of course, flavors. When the average person thinks about a chef, the first thing they want to see the chef is do is cut something up really fast and really fancy, both of which I have not mastered although I have been trained. Those skills are we as chefs usually acquire after years int he game and cutting something other than out fingers LOL every single day.
Knife cuts were quite the struggle for me in culinary school because I can be a tad bit lazy and I also didn't understand why the cuts were so important until my knife cuts were constantly being critiqued all the time. My knife cuts used to be so terrible that they brought my grade down from an A to a B :-/ I know, tell me about it!
Anyway, straight to the point, the number one reason knife cuts are so important is so that all the ingredients can cook evenly at the same temperature and time. Imagine making a soup with root vegetables, or trying to make mashed potatoes and just when you think everything is done, it's not because you have some small pieces that cooked fast and all the way through meanwhile your larger cuts are taking forever slowing the entire cooking process down. Knife cuts done well also make great for presentation as well and the aesthetics of plating because we eat with ours eyes first, then our mouths.
Brunoise was my LEAST favorite knife cuts. -_-
Basic Knife Cut Measurements:
Batonnet: 1/4 x 1/4 x 1/4
Julienne: 1/8 x 1/8x 2"
Fine Julienne: 1/16 x 1/16 x 2"
Brunoise: 1/8 x 1/8x 1/8
Small Dice: 1/4 x 1/4 x 1/4
Medium dice: 1/2 x 1/2 x 1/2
Large Dice: 3/4 x 3/4 x 3/4