Judges
Corner
Q&A's from the experts
1.
Why does the aroma and bitterness seem to fade out after a few months in the
bottle?
2.
I have made 2 identical batches of beer 8 months apart and it seems that the
second batch was not even 1/2 as bitter as my first batch.
I was using the same batch of hops. Could you please explain why?
Greg
Burns replies:
I'm
going to answer both of these questions together because they are related.
Both
situations arise due to oxidation of alpha acids contained in raw hops, or iso-alpha
acids dissolved in finished beer.
"Hops
are susceptible to oxidation that reduces bittering potential and causes
degradation of aroma components, so brewers must take care in selecting and
storing hops once they have been purchased. The three components that
contribute to oxidation are oxygen, heat and time. Eliminate all three and
your hops will be fine, but the presence of any one component can give you
trouble. The most easily controlled
is heat. If you keep them frozen, whether in whole, plug or pellet
form, you can greatly reduce oxidation. Shelf life can be improved
considerably with the elimination of oxygen in the package, as it is when
packaged under vacuum or with inert gas. Even when the iso-alpha acids are
safely dissolved in the finished beer in your keg or bottle, there can be
losses. There are oxidation reactions that can reduce the bitterness of beer
over extended storage periods and create "cheesy" aromas in its
place." [ Storing Hops - Zymurgy Special 1997 ]
Watching
your handling techniques for ferment finished beer would be an area to review if
you find large bitterness losses in your finished beer after a few months. No
splashing when racking or bottling. If you are having trouble with consistency
in hop bitterness from batch to batch, you may consider the freshness of the
hops you are using. Use a
standardised method to calculate the bitterness that you are adding to the beer.
IBU or International Bitterness Units calculation is an important factor in
being able to repeat recipes. Use a good formula and keep records of you
brewing. [back to
top]
Is
it safe to use brass fittings in a brew kettle or other brewing equipment?
Colin
Campbell replies:
To
determine if a material is safe to use in the brewing environment we should be
able to answer the following three questions with a definitive YES.
1. Do we know what the composition
of the material is?
Brass
is a nonferrous metal usually composed primarily of mixtures of copper and
zinc metal. Most common brasses are typically around 70% copper and 30% zinc
but can vary to from 95% copper/5 % zinc and other metals to 50% copper/50%
zinc and other metals. Many brasses contain tin, iron and lead among other
things.
2.
Is the material resistant to corrosion by acidic to slightly acid
solutions within the normal temperature ranges of brewing (0 - 100 degrees
Celsius)?
Most
brass materials have good to excellent corrosion resistance under these
conditions.
3.
Are we certain that the material does not contain any constituents which
may be toxic.
Should
the material corrode (dissolve into our beer), are there any potentially
toxic constituents in the metal we need to be concerned about.
In
the case of a typical yellow brass, 65% Copper/35% Zinc, neither the copper
or zinc are known to have any significant health risks at low exposure
levels. Unfortunately, some brasses contain lead, which is highly toxic and
can be readily dissolved in hot, acidic solutions (read beer).
Conclusion:
Unless the exact nature and composition of the brass material is known I would
personally not want to use it in my brewing environment. As a general rule, I
prefer to use only good quality stainless steel and food grade plastics.
For
more information on the composition and properties of various materials you can
check out http://www.matweb.com
[back to top]
Do
I really need to clean my boiling pot?
John
Gray replies:
The
question of cleanliness is an easy question to answer. Yes, you do want to keep
your brew pot clean just as you would all of your equipment and the area in
which you are brewing.
The
real question, I think, is does your brew pot need to be sanitized?
Due
to the fact you are boiling liquid, pasteurization or sanitization is occurring
naturally to everything the liquid or steam come in contact with. However, be
aware that other surfaces, such as handles or taps, may be subject to
contamination or cross contamination (cross contamination is the transfer of
bacteria between equipment and/or work surfaces/ ingredients). A quick fix for
this is to fill a spray bottle with sanitizer and spray any handles, taps, or
other work surfaces that could be potential bacterial hazards.
Always
be aware how clean your hands and equipment are and remember
that cleanliness is next to goodliness.
[back to top]
|
