Rieska is a Finnish unleavened flatbread that has been prepared across the country since ancient times. At its simplest, the bread consists of flour, water, and salt, although the ingredients for its preparation vary from one region to another, as do its texture and thickness, ranging from thin, crispy and cracker-like, to thick, dense, and bready.
The most common type of flour used for the preparation of this flatbread is barley (which makes barley rieska or ohrarieska in Finnish), but rye (ruisrieska), oats, or mashed potatoes (perunarieska) are also often used instead of barley.
In the past, rieska flatbread formed a staple in the Finnish diet throughout the country, and it used to be baked on hot stones, which were later replaced with hot ovens. Its status changed, however, with the introduction of leavened bread, and even though rieska is still a staple in northern Finland, people in the south-east and south-west prepare it only on weekends or in case of unexpected guests.