Oats fall into the category of 'adjunct' which covers anything that is a non-malt source of fermentable sugar. ... Oats contain starches and gums (beta glucan) which thicken the body of a beer. These remain in the beer after fermentation and can be perceived as an oily slickness in the mouth.

What does flaked oats do to beer?

Flaked Oats contain high levels of lipids, beta glucans and gums, which impart a silky mouthfeel and creaminess to beer.

What kind of oats do you use for brewing?

You will want to use "quick oats" as they have been pre-gelatinized. Regular traditional oats will need to be boiled first to gelatanize them. Quick oats can go directly into the mash as-is. I've used them in several brews and they work great.