Daniel Serra, a PhD student in archaeology studying Viking age food culture, has created a blog, Eldrimner - a blog about medieval and viking age food, on which he shares his experiences with cooking at a Norse historical village.
The series of blog entries include his experiements with malt, recovering used salt, and sweeteners such as honey.
From a recent post:
In preparation for another experiment I needed some mustard seeds ground. The lack of proper mortars found from the Viking Age did however give me some problems and an opportunity to test out another hypothesis of mine. The use of soapstone vessels as mortars for grinding similar to the ancient Roman mortaria. For this cooking experience I used a simple stone, a soapstone vessel and some mustard seeds. The mustard seeds were poured in to the bowl and I commenced to crush/grind the seeds with a circular motion. It went quite well and it was nt long before I had managed to grind all of the seeds.