Ancient Brewhouses

One of the blogs I follow is Zythophile, a blog about all sorts of beer.
I was also once an archaeologist - so I found his post on brewing Viking beer fascinating.
The structures involved have been known about for a long time, but they have always been interpreted as saunas or bath-houses before - which shows the importance of interpretation of finds! A wrong interpretation can completely skew ideas about the site or even an entire culture in some cases. These buildings were usually next to the drinking hall of a settlement or farm, and though it is well known that Vikings liked to be clean, it probably makes more sense to brew the ale next door to where you intend to drink it. The one in the picture on Zythophile's blog is in the Orkneys. It has a stone box with a hole in one side to light the fire, and the cauldron would have rested on top of the walls of it.
Merryn Dineley, the archaeologist, and her husband Graham, who is a craft brewer, have also been doing experimental archaeology on the subject, which is to say they actually brewed some beer, using the original equipment at Bressay Heritage Centre in Shetland! In this case, the stone trough was Bronze Age, and they got out a very drinkable ale, rather like a barley wine. They heated the mash with hot stones, as this one is built into the ground with no room underneath to light a fire.

Strangely, on the same day as I came across this story, I also found an archived post from Moore's Group Blog, which is an archaeological blog. In October 2007, they posted "Ale, brewing and fulach fiadh: Archaeology Ireland" which looks at Irish ancient monuments which consist of a horseshoe shaped mound and an associated trough. No-one was sure what they were for, apart from agreeing that water was heated in the troughs by putting hot rocks in. So they, too, did some experimental archaeology, after much research about brewing around Europe, and the discovery of a similar method of heating the wort which is still used in Finland for a traditional ale. Originally, the liquid would have fermented using wild yeast which is in the air - lambic beers in Belgium are still made by this method.
There's an interesting digression about magic wands, too - if you kept using the same stick to stir the brew, it made fermentation easier, because some of the yeast from last time was still on the stick.
They got a drinkable ale in three days, but pointed out that the hard work was all associated with processing the barley. They used the spent grain after the ale was brewed to bake bread and feed to the cattle. (When I was growing up, bread buns made with brewer's yeast were known as barm cakes.)
They also have a new post on brewing, including a story about St Brigid apparently making beer from bath water, for the 1st Feb this year.