Thanks for the explanation.
Yes, those can be used for flavoring beer, instead of, or in addition to hops. That would make it a gruit (or gruyt, grut, etc.), which is just a name for a type (or style) of beer containing herbs.
Now the beer itself is still malt based, using
malted grain. The grain could be barley, wheat, oats, rye, sorghum, millet, etc. or any combination of those.
Critical point is, a (fairly large) percentage of the grain used must be malted, which means it contains enzymes in the kernels, that will convert the starches into sugars during a process called the
mash. The mash is simply soaking the
milled grain in 65-70C water for an hour or so. That's usually followed by separating the wort (the water containing the sugars) from the spent grain.
You can then add anything you want to that wort during the boil, or after, to make delicious beverages, such as beer, gruit, malt beverages, alcoholic or not.
Ale a style of beer where the wort is fermented with an
ale yeast.
Lagers are a style of beer fermented with a
lager yeast.
After fermenting Lagers are typically cold stored ("
lagered") for a few weeks to a few months to thoroughly become clear. That process is called
lagering.
They're all beer.
Gruit is a beer, and you probably would use an ale yeast (or perhaps a wild yeast).
From Wikipedia:
Gruit (alternately
grut or
gruyt) is a herb mixture used for bittering and flavouring
beer, popular before the extensive use of
hops.
The terms gruit and grut ale may also refer to the beverage produced using gruit. Historically, gruit is the term used in the historic
Low Countries and the
Holy Roman Empire (westernmost Germany).
Today, however, gruit is a colloquial term for any beer seasoned with gruit-like herbs.