It has also been made by blending a conventional ale with a conventional lager after fermentation. Indigenous, wild yeasts and other microorganisms settle on the exposed surface of the wort as it cools and begin spontaneous fermentation. They are often sweetened with fruit flavorings and generally prized the world over. 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.
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. They cannot be fermented again to make more beer. A brewer called Harwood had the idea of brewing a beer that united the flavours of all three. This was about 1720.