Over the next few weeks I'll be (finally) coming back to the Viking food topic.  I just finished entering a big competition with a research paper on reconstructing Viking cooking, and I've learned a lot over the last 6 months. 

After getting feedback from the competition, the paper needs some serious editing, but once that's done I'm going to try and make it available. 

In the meantime, I've been experimenting (as part of the research for the paper) with recreating some Viking bread, like those found in cremation graves in Birka and elsewhere.  One of the finds from Birka clearly shows prick marks on the surface, which hints at them being intended to keep a long time.  The prick marks are (I assert) similar to those on modern pilot bread.  They are intended to increase the surface area so that the bread will dry out completely, thus keeping longer.

In recreating them, I looked at some chemical analysis of the bread remains that suggest that most of them were predominantly made from barley, although oats, rye, flax, green peas, and a little wheat also appear.  They contain comparatively few fats, again suggesting that they were intended to keep.

I made mine with about half barley flour, and half a mixture of oat flour, ground flax seed, rye flour, and (in some) green pea flour.

The resulting mix should be about 2 cups.  Then I added a bit of salt, and mixed in some liquid until a stiff dough comes together.  I tried different combinations of water, honey, buttermilk, and goats milk.  Personally, I liked the goats milk ones the best.  I kneeded mine for a while to make sure everything was as together as it was going to get, then divided the dough into two pieces.

The pieces were then flattened into rounds.  Most of the archeological evidence suggests 8 -12 cm. across, and 1-2 cm high.

Then I pricked the surface, and baked them at 300° for around 30 minutes.  This results in a fairly soft bread good for eating fresh.  You'd have to bake them either quite a bit longer, or at a higher temp to get the to dry out hard.

The resulting breads were very good with cheese or green pea spread.