It's a beer world after all!
Brandhefe literally means “burnt yeast.”It's the German name for the brownish residues found on the sides of an
emptied fermenting vessel, brandhefe is usually seen as a ring near the top of the vessel.It is composed of dried-
up yeast, albumen, and hop resins and must be carefully removed after each use of a fermenting vessel. It is a
tough, tacky material, and is not always easy to remove. Contrary to its name, it does not consist primarily of
yeast, but actually contains proteins and hop resins that make it dark and sticky.

The brandhefe is mainly the dried remains of the froth built during the early stages of bottom fermentation,
the so-called Kräusen. This froth, which is built up by evolving carbon dioxide, “washes out” undesirable flavors,
including some rougher-tasting hop components, from the fermenting young beer.The Kräusen turns dark and
eventually brown or even black as the contained hop resins dry out. In the latest phase of primary fermentation,
the froth collapses and if not skimmed off sticks to the sides of the vessel, where it can be removed after
the  vessel is emptied.

Traditional lager brewing recipes call for the removal of all dark parts of the Kräusen before racking
the beer to a maturation tank, an operation that can only be performed when open fermenters are used
in traditional lager beer breweries.

In modern cylindroconical fermenters most of the brandhefe will stick to the inner walls or ceiling of the
fermenting vessel, but several brewers argue that some of the harsh bitterness in certain modern pilsners
may be the result of incomplete removal of brandhefe.

====================

Citric Acid is an organic acid found in beer normally within the range of 50 to 250 parts per million.It is produced
as a result of yeast metabolism and is a key component of the tricarboxylic acid cycle, which is also referred to
as the Krebs or citric acid cycle. Although it contributes to the overall acidity of the beer, citric acid has little impact
on the overall flavor. It is sometimes added to increase the acidity of some low-alcohol and nonalcoholic beers
where incomplete fermentation fails to increase acidity to an appropriate level.

Craft brewers and homebrewers have occasionally used additions of citric acid to lend some tartness to
Belgian-style witbier; although some tartness is traditional, it has historically been the result of lactic bacterial
activity.Citric acid has also been used as a cleaning agent, particularly in the removal of “beer-stone” from
fermentation vessels.

======================

Finally I'd like answer a question from Tom Reynolds about saisons. They were often brewed by farmers
during the winter months (when there was less actual farming to do). By the time spring came around, the beer
would be ready, and would help to slake the farmers’ thirst long hot days. If you're looking for a rereshing, tasty
beer you should give this style a try.  I'ts one of my favorites.

===============

Hope you found this month's column of interest.  If you have any questions about beer or brewing
or just want to submit a word for me to discuss here just
e-mail it to me.

Thanks and Cheers!
Burnt Yeast / Citric Acid / Saisons
A new column by
Jack O'Reilly
Jack O'Reilly attended the
famous Siebel Institute/ World
Brewing Academy in Chicago.
I'm very excited to be part of the BeerNexus team.  I think my many years in the
beer business both as a brewer and manger will enable me to explain and
investigate many topics of interest for those who really love craft beer.
Hope you join me every month.  
Cheers
!
Jack
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More by Jack: #1, #2, #3, #4, #5, #6, #7, #8, #9, #10, #11,
#!2, #13, #14, #15, #16, #17, #18, #19, #20