Bock is a style of lager beer which originated in Germany. It was traditionally brewed in the fall, at the end of the growing season, when barley and hops were at their peak. It was “largered” all winter and enjoyed in the spring at the beginning of the new brewing season. Bocks can be pale (helles) or dark (dunkles) and there are double (doppel) bocks which are extra strong. Bocks are usually strong beers made with lots of malt yielding a very full-bodied, alcoholic beer.
A persistent myth has been that bock beers are made from the dregs at the bottom of a barrel when they are cleaned in the spring. This probably seemed logical because of the heavier body and higher strength of bocks. From a brewing standpoint, this is clearly impossible for two reasons: 1) The “dregs” left after fermentation are unfermentable, which is exactly why they are left over. They cannot be fermented again to make more beer. 2) Any attempt to re-use the “dregs” would probably result in serious bacterial contamination and a product which does not resemble beer as we know it.