Home' Hospitality Business : HB NOV 2017 Contents into accessible sugar. As this occurs, the barley seed has the energy it
needs to shoot up towards the sun. Or, for our pur poses, the brewer’s
yeast can now begin its work of turning sweet-sugary wort (the liquid
produced in the mash) into beer.
The brewer’s job is to essentially emulate those conditions in the
mash kettle by mixing grain with water that is precisely heated to the
temperature most optimal for the desired enzyme activity. Different
enzymes become active at different temperatures, and each enzyme will
have a different effect on the beer. For example Alpha-amylase enzymes
which prefer a temperature ranging from 66-71°C, will hack up those
starch molecules into relatively larger pieces; some of which are too
large for the yeast to completely consume. This residual starch gives a
beer more body, and a less-dry finish (think Porter). By compar ison,
Beta-amylase enzymes become active between 54 and 66°C.The Beta-
amylase enzyme breaks those same starches into smaller pieces. These
smaller starch particles are more easily consumed by the yeast, resulting
in a more fer mentable wort and a generally dryer beer (think Pilsner).
The mash is the part of the process where science overlaps with art
and the choices a brewer makes can have a big impact on the final beer.
Where two cooks can follow the same recipe and produce dramatically
different meals, two brewers can produce an equally var ied beer based
solely on how each brewer decides to approach the mash.
Once the grain has been mashed for about one hour, the liquid is
filtered off and added to the ‘boil kettle’ where it is typically boiled for
60 to 90 minutes. There are three primary reasons the wort must be
boiled before we move on to fer mentation . . .
Much in the way that acidity is key to a wine’s balance, hops are the
backbone of a beer. Without some for m of bitterness to balance malt
sweetness, a beer would taste flabby and sweet, relatively speaking.
However, in order to extract those bitter oils from the hop flowers,
they must be boiled for a per iod of time. How long you boil the hops
deter mines how much bitter ness is imparted into the beer. If boiled for
a full 60 minutes, you will extract most of the hops bitter ness potential
and ‘blow off ’ most of its volatile flavour and aromatic properties. If you
add the hops later in the boil (or even after it has concluded altogether)
you will extract less bitter ness, while preserving the fruity/flowery/
herbal qualities of the hop. How and when you add your hops to the
boil dramatically impacts the flavour, aroma, and style of the final beer.
DMS (dimethyl sulphide) is a natural bi-product of malting and
mashing grain. It tends to taste like cooked cor n (sometimes cabbage),
and is generally considered undesirable in beer. Fortunately, DMS is
a volatile compound. So by boiling wort for approximately 60 to 90
minutes, you effectively ‘blow off ’ any detectable levels of DMS.
Grain is naturally loaded with a plethora of wild yeast and bacter ia and
while the war m temperatures of the mash will kill off the major ity of
those microbes, it won’t kill all of them. If left to survive, these microbes
would likely go on to produce lactic acid and other manner of off-
flavours in the beer. However, by boiling the wort, brewers effectively
pasteur ise it, which leaves a blank canvas for the selected mono-culture
of brewer’s yeast to do its work in peace, and produce a beer with the
specific flavours and aromas that each brewer intended.
The brewer’s job is not to make beer, so much as it is to create the
perfect conditions for yeast to do all of the real work. Once a brewer
has selected the r ight ingredients, mashed the grain, and then infused
the resulting sugary liquid with hops, it’s time to pitch the desired yeast
strain and sit back and watch as hundreds of billions of tiny yeast cells
consume all that sugary wort you made and produce alcohol (and CO2)
as a deliciously intoxicating by-product.
Without question, to master the art of brewing good beer one must
master the art of fer mentation. Add too much yeast and you run the
r isk of producing a blander beer, or one that can have a cidery, green
apple quality (which comes from a compound called acetaldehyde).
Add too little, and the yeast may end up producing an over-abundance
of fruity esters and other undesirable flavours. Even more crucial to a
good fer mentation is maintaining a consistent temperature, usually with
a slow r ise towards the end (aka a diacetyl rest).This slow r ise in the
temperature is done to elevate the yeast’s metabolism just as they begin
to run out of food.This encourages the yeast to continue scavenging
other fer mentation by-products, resulting in a generally cleaner and
While the difference between a well-fer mented beer and a poorly-
fer mented beer may not be immediately obvious to some, fer mentation
health is crucial. It can effect flavour, aroma, mouth feel, head retention,
and even shelf life. A bad recipe fer mented well typically makes for a far
better beer than a good recipe that has undergone a less-than-optimal
fer mentation. Like a shepherd tending to his flock, the fer mentation is
the brewer’s biggest responsibility when it comes to making good beer.
So the next time you reach for your favour ite brew, dear reader,
realise that it is much more than a fizzy yellow beverage. It’s the product
of weeks of hard work and thousands of years of exper imentation. Beer
is one part art, one part science, one part cooking, and perhaps even a
dash of divinity is somewhere in the mix. But one thing for sure, it’s a
beverage that is more than the sum of its parts. n
Adding grain to heated
water is known as ‘mashing in’
A head of foamy ‘krausen’
(yeast and wort proteins) will
form on top of a beer during the
peak of fermentation
TheShout NZ | HOSPITALITY BUSINESS | November 2017 | 15
Links Archive HB OCT 2017 HB DEC 2017 - JAN 2018 Navigation Previous Page Next Page