Cereal Grain Used in Beer Brewing

This page is the CodyCross answer for the clue below from Physics, Group 1884, Puzzle 4 (Spectroscopy).

Question is: Cereal Grain Used in Beer Brewing

and the answer is: BARLEY

Word Meaning:

BARLEY — A cereal of the species Hordeum vulgare, or its grains, often used as food or to make beer and other malted drinks.

Definitions from Wiktionary.