Key Difference:  Oat is a cereal grain cultivated for its seed. It is derived from the annual grass known as Avena Sativa. All the different types of oats are basically derived from oat groats which are hulled and cleaned oats.

Oat is a popular cereal which is scientifically known by the name of Avena sative L. It belongs to the Genus Avena of Family Gramineae.  This cereal crop is also used as a fodder crop. The use of this crop has been taking place since a long time, and therefore it is also known as the Old world cereal plant. The grains derived from this cereal plant are also known as Oats. Oats are considered to be powerhouse of fibers and proteins. It also contains beta glucan which helps in lowering the cholesterol re-absorption. These are whole grains which are usually preferred for making breakfast porridge.

The oat grain is usually preferred with all its valuable nutrients, and therefore only the outer shell known as hull is removed. This hull is inedible and therefore must be removed. There are many different types of oats. Cultivated varieties are annuals, however there are perennial varieties of oats too. These are the common form of oats-

Whole Oat Groats - This form of Oats is the one which preserves most of the nutrients of oats as only the outermost inedible hull is removed of these oats. They are also known as simply whole oats sometimes. These oats possess a nutty oat flavor. The main drawback of these oats is that they do not cook fast and take a long time to cook.

Steel cut (pinhead) Oats – These are also known as Irish oats. These are just oat groats but have been cut into two or three pieces. The cutting takes place with steel blades. This process helps in reducing the size of oat grains and therefore it takes lesser time to cook. Along with Oat groats it is also categorized into the least processed types of oats.  They are chewy in texture.

Jumbo Rolled Oats/flakes – These are the raw whole oats which are treated with steam firstly. This process makes them softer and then these oats are flattened by placing them between rollers. This shapes them into flakes. They are usually used raw in muesli.

Rolled Oats – Rolled oats and jumbo rolled oats are similar, the only difference between the two is that instead of using whole grout oats it takes steel cut oats and then these oats are rolled after going through the process of steaming. Therefore, their size is also smaller in comparison to jumbo rolled oats.

Oatmeal - This usually refers to the oats which are derived by breaking up the oats. This process makes use of grooved rolls to get different grades/varieties of oatmeal. It may produce coarse or medium of fine type of oatmeal. These are thicker in comparison to rolled oats. Oatmeal also takes longer time to cook.  The term is also used in context to meal prepared by using this oatmeal.

Oat flour- Many people think oatmeal and oat flour are same. However, oat flour is finer than in comparison to oatmeal. Oat grains are grinded and then sieved to make this floor. It is usually used for making cakes or bread. It is known for its bland flavour. It is also used with wheat flour for making different types of breads.

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