NOTE: In the 2015 BJCP Style Guidelines, Traditional Bock is not classified as Style 6C Dunkles Bock in Category 6 Amber Malty European Lager which groups amber-colored, German-origin, bottom-fermented lagerbiers that have a malty balance and are vollbier to starkbier in strength.
A traditional bock is a beer which was usually brewed for the cold hard winters in Bavaria. These can be some of the heaviest and maltiest beers in the world.
These smooth rich beers are made to be sipped by the fireside. In Germany, a bockbier is usually a brewed to between 6.5 and 8% ABV. There is some overlap here with the dopplebocks but in Germany a traditional bock is more of a category than a subcategory.
To have the name bock on the label, it must have a minimum OG of 1.066. Most bocks are brewed for a specific part of the cold season there and have their own distinctive names. In Germany, many consider each sub-category to be a separate style.
Traditional Bock Brewing Tips
Bocks were traditionally decocted, producing a beer rich in malt complexity with some caramel notes as well.
There are ways to simulate the flavors and color of a decoction mash. The use of a small amount of melanoidin malt is one method.
Most traditional bocks are brewed with Munich or Vienna malts to get the melanoidin rich flavors characteristic of the style. The darker the Munich malt, the more toasty and bready notes you will get.
On the extreme end of the melanoidin rich malt scale is melanoidin malt made by the Weyermann Malts. Some believe that Weyermann produced the malts so those breweries that couldn't perform the traditional German decoction mash could still get the same flavors in their beer. Many, however, find that it is a poor substitute for the traditional method.
Longer boils will produce some melanoidins in the wort. I've heard of some homebrewers applying extended boils of up to 4 hours to attain the proper flavor profiles in their bocks.
The best bet would be to use a combination of Munich in the base malt bill, some dark crystal malt for richness of color and flavor, and melanoidin malts to simulate the decoction mash, and longer extended boils for added richness and natural melanoidin production.
Munich malt can be used for a dunkel bock as up to 90%+ of the grain bill according to Darryl Richman who wrote the style book Bock. This would produce a more traditional bock using the original malt available to brewers in Munich before crystal, chocolate, or roasted barley were available.
Traditional Bock Description
Aroma: You will note strong malt aromas with rich
melanoidins and toasted malt nuances. There will be almost no hop
aroma. Since it is a strong beer, some alcohol may be noticed.
Traditional bocks are lagers so there should be no diacetyl and only low
to no fruity esters evident.
Appearance: The colors are usually described as light copper
to brown with garnet highlights. The beer should be very clear from the
long cold lagering period. Bocks should have a large smooth off-white
head which lingers for a while.
Flavor: Bockbiers are slightly sweet with intense bready
malt flavors and no hop aroma of flavor at all. The complexity can come
from many places including the use of Munich and Vienna malts, crystal,
chocolate, and other specialty malts, decoction mashing, and long
extended boils. The hop bitterness should be just enough to offset some
of the sweet maltiness, but still allow some residual sweetness to
linger on the palate. It is a fairly well attenuated beer so it should
not be cloyingly sweet at all. This lager should finish clean with no
fruity esters or diacetyl, no hop flavors, and definitely no burnt
Mouthfeel: Bocks are medium-full bodied beers with moderate
carbonation. The higher alcohol content may show with a warming
sensation. This is partly why they are traditionally sipped during the
cold winters in Bavaria. The beer should be crafted so the alcohol is
not hot by paying close attention to the fermentation temperatures.
They are fairly heavy malty beers but should still be very smooth with
no harsh or astringent character.
Overall Impression: A slightly sweet, strong, dark very bready malty lager beer.
Comments: If you can do a decoction mash, it will produce a
traditional bock with more authentic flavors. For the majority of
homebrewers who either can't or don't want to, use one the methods
mentioned above to simulate those flavors. It won't be quite the same,
but with some experimentation in the grain bill and employing an
extended boil, you may be able to come pretty close. The Munich malt
may produce some fruity overtones in this beer but the yeast should not.
Many of the yeast strains employed for fermenting the traditional
bocks have "Bavarian" in the name.
History: Traditional bocks were not originally brewed in the
area which made them famous. They were originally brewed in the city
of Einbeck. They became so popular in Munich that the citizens quit
importing the dark lagers from Einbeck and began mass producing their
own version, the bockbiers of today. There are several stories of how
the name Bock came to be. One is that it is a gradual transition in
pronunciation of the Bavarian word for Einbeck, Ainpoeckish Pier to
simply Poeck and finally to Bock. Another is that the word Einbeck was
pronounced more like "Einpock", which of course eventually became Bock.
It just so happens that the word bock in German also means "billy goat"
or "goat", so you will find that moniker on many labels.
Ingredients: The ingredients vary from 90%+ Munich malt to
less than 25% Munich malt with the rest Pilsner or pale malt.
Traditionally Munich malt is used for most of the grain bill. When less
Munich is used, there may be some very small amount of dark roasted
malts employed for color. Continental European hops, especially noble
German varieties, should be used. A good clean lager yeast is
essential. For the water, you can emulate that of Munich which has
moderate carbonate levels.
Commercial Examples: Einbecker Ur-Bock Dunkel, Pennsylvania
Brewing St. Nick Bock, Aass Bock, Great Lakes Rockefeller Bock,
Stegmaier Brewhouse Bock.
References: Information for this page was adapted from the 2008 BJCP Style Guidelines, the page on Bockbier from The German Beer Institute, The German Beer Portal for North America, and Brewing Classic Styles, 80 Winning Recipes Anyone Can Brew, by Jamil Zainasheff and John J. Palmer, Designing Great Beers, The Ultimate Guide to Brewing Classic Beer Styles, by Ray Daniels, and Bock by Darryl Richman.