Ogma was a brewer, and so was Goibhniu, the smith god. Brigid too was a brewer, and there are many references to the consumption of beer in medieval Celtic texts. In that context the recent find that six specially constructed ditches previously excavated at Eberdingen-Hochdorf a 2,550-year-old Celtic settlement, were used to make high-quality barley malt, an essential beer ingredient. (You may recall Hochdorf as a principle Celtic site, where among other important finds in the museum is the grave of the Hochdorf prince.)
Archaeobotanist Hans-Peter Stika of the University of Hohenheim in Stuttgart has published a paper in which he discusses the results of chemical analysis of some of the thousands of charred grains of barley found in the six ditches. The paper, published on January 4, 20 in Archaeological and Anthropological Sciences is titled “Early Iron Age and Late Mediaeval malt finds from Germany—attempts at reconstruction of early Celtic brewing and the taste of Celtic beer.”
You can read the abstract, linked above, or download the .pdf of the paper, but the analysis of the malt, in the context of what we know about early brewing in the La Tène Period, fifth –fourth century BCE, Stika suggests that the beer would probably have been somewhat smokey in character, with a sour taste (keep in mind that beer in this era would not have used hops).