There are many reasons for brewers to use various flaked grains. Some intensify a certain characteristic, add a unique aroma to the beer, while others affect the color and clarity or boost the volume of fermentable sugars. Depending on the beer style and purpose you can commonly choose among flaked maize, barley, oat and wheat.
Their production method starts by steam-cooking, then they rolled flat between hot cylinders and finally dried. The heat and pressure pre-gelatinize the starch, so they can simply added directly to the mash. Depending on the grain the addition may occur at beginning of the mash, or you can perform a protein rest, if needed.
Flaked grains are not malted at all, therefor do not include any enzymes to break down their starch, but luckily they can utilize the enzymes from malt. Nevertheless brewers have to be careful of their ratio and how to compose the rest of the grain bill.
Flaked wheat
This cereal imparts more intense flavours than the malted wheat. Flaked wheat ensures a hazy beer.
Result: Increased body and head retention.
Flavour: Spicy, bready.
Usage: Witbier, Weizen, NEIPA.
Flaked oat
The excess in beta-glucans results in haziness. It could also affect filtration, so you might want to add rice hulls.
Result: Additional body, head retention, haziness.
Flavour: Silky mouthfeel.
Usage: Oatmeal Stout, Porter, Witbier, NEIPA.
Flaked maize
Brewing with corn is best done by adding flakes. It has little protein and can be added directly to your mash.
Result: Milder taste with a dry, crispy finish.
Flavour: Sweet, less malty.
Usage: Light Pilsners.
Flaked barley
These cereals will increase the volume of fermentable sugars, without adding body or taste. Some haziness might occur.
Result: Stronger head retention, smoother flavour.
Flavour: Slightly grainy.
Usage: Stouts.