It's a beer world after all!
Before stainless seed, oak barrels were the typical vessel used to store and transport beer. Oak was favored
above other woods because its structure makes it watertight. Oak is also bendable - a quality crucial for the
reproduction of barrel staves.  All species of oak can impart their own flavors to beer, but long ago this was
rarely desired.  In some cases, the barrel were line with pitch (a resin extracted from the conifer tree) which
protected the beer from contamination of flavor. French Oak is known for it's fine, mild character and is preferred
by many wine producers.  As a result, it is usually much more expensive than American Oak.

As craft breweries became more popular, especially in the US, many brewers have looked for new and unique
ways to enhance the flavor of their beers.  This lead to the use of oak barrels that once housed spirits like
bourbon or whiskey. Oak itself contains a number of flavors, and those flavors differ widely depending on the
species, the growing area and the treatment of the wood.  A range of compounds knows as lactones are
responsible for many of the aromas and flavors associated with "oak."  These are derived from lipids within
the wood and tend to impart a coconut-like flavor, especially in American Oak. A prevelant secondary
characteristic is the vanilla-like aromatics of the compound vanillin.

Oak also contains astringent tannins, which can leach into beer over time and clash with hop bitterness.

New Oak barrels may also be used for aging beer but are far less common due to higher costs.  Other products
such as oak chips, cubes, power, shavings or immersible staves are useful alternatives to acquire the desired new
oak flavor and are all widely accessible to brewers.


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,  mainly to remove “beer-stone” from fermentation vessels.


A Beer Analyzer is used to measure various components in beer The name is given to a range of commercial
instruments marketed for their utility in measuring these components of beer as well as wort.  The best known of
these instruments is the SCABA, a system launched in 1979 that measures specific gravity, alcohol, pH, and color.
Thus, the instrument will provide calculated data for Original Extract, Apparent Extract, Spirit Indication, Apparent
Fermentation, and Real Fermentation.


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!
Oak Barrels  // Citric Acid // Beer Analyzer
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.  
More by Jack: #1, #2, #3, #4, #5, #6, #7, #8, #9, #10, #11,
#!2, #13, #14, #15, #16, #17