>>Beer is one of the oldest beverages known to man. We have tabulations, written documents,
of brewing to the fourth century BC. If we think about where it came from, it was probably
an accident. All we needed was a sugar and wild yeast, and the yeast could convert that
sugar into alcohol, which of course early man found enjoyable. To make beer as a fermented
process we know that that goes back to 4000 BC where we have written documents that actually
explain the process. Now, the beer that the ancients knew was probably not the same beer
that we drink today. It had similar components. Most often it was barley, water, and yeast.
But originally there were lots of different spices that were used. It wasn't until around
the 700s A.D. that we got into using hops in beer. This became the main definition of
beer in 1516 with beer purity laws, which stated that beer should consist of malted
barley, hops, yeast, and water. The malted barley gives us the sugar that is required
to create ethanol plus it gives us the amino acids and the lipids necessary for healthy
yeast growth. The hops adds flavor components to balance the sugary taste of the malt, but
it also adds some essential oils that extends the life of the beer. The yeast does the heavy
lifting. It is there to convert sugar into ethanol. The ethanol is important because
it's actually antibacterial, which means that beer will last longer in many cases than the
grain might have. And water. Water is often overlooked, but it turns out that the water
is essential to make sure that the yeast will process the carbohydrates well. This means
that we have to have the right pH, and we have to have the right calcium and magnesium
levels.
Now the process is not overly difficult, but there's a series of steps. Let's just look
at it from the brewing standpoint, and then we'll talk about the chemistry of each of
those steps. First, malting. We have to take the barley and turn it into malt. We're more
or less getting it wet so it'll start to germinate. We don't want to germinate fully, so therefore
we stop that by kilning. Kilning just means drying it out. So we're going to dry out our
malted barley, and with this we can also add some other flavor components. We can heat
it up a little bit to get a little caramelization, or we can really heat it up to get a nice
bitter chocolate type taste components.
Once we've kilned it, we're going to need to actually grind it, and then we can start
the mashing process. The mashing process is going to add water so that we can start to
hydrolyze our sugars, bringing the temperature up so that we can get the optimum temperature
range so that we can get the starch hydrolysis enzymes, alpha-amylase and beta-amylase. Now
at this point, we don't want to boil it. It turns out if we get too hot, we'll actually
deactivate those two enzymes, and we'll be left with lots of maltose in the solution
and not the ethanol that we're often looking for in beer, giving the beer a very sweet
flavor. So we leave it there for a while and let those two enzymes really convert much
of the starches into our small fermentationable sugars.
At that point now we've converted most of those. We need to remove the wort, which is
going to be our dissolved components, away from our grain, our husks. Then we're going
to take that wort and bring it up to a boil. When we bring that wort up to a boil, we're
a doing couple of things. First of all, we're making sure that we're sterilizing the entire
wort. This is important because when we introduce our yeast, we want to make sure it's the yeast
we want and not a wild yeast or any other bacteria. We also at this point will introduce
hops. There's several places where we can introduce hops, but at the boil what we'll
be doing is extracting out of the hops the alpha and beta acids that we need to add flavor
components plus some other essential oils that'll help stabilize the beer. We then filter
out the hops, and we bring that down to a lower temperature so that we can have the
yeast work on the process. Now what is the yeast doing? The yeast is converting the sugars
into ethanol. This is an important role. We don't have beer unless we have the ethanol.
Now the process starts out as aerobic respiration and is going to go to anaerobic respiration.
It's this anaerobic respiration that gets us to the ethanol that is often associated
with beer. Once the fermentation is done, we have something that really resembles beer.
But we're going to let that age, sometimes just a few days and other cases maybe months,
so that we can get different components of taste to either develop or to be inhibited.
At that point we need to do second fermentation because as we know, beer is carbonated. The
second fermentation is focused less on creation of ethanol and more on the creation of carbon
dioxide. The carbon dioxide carbonates the beer and gives us the mouth feel that we're
used to. If we think about historically, it turns out the ethanol and the carbon dioxide
were important for this to stay stable. The lack of oxygen and the ethanol were both very
important in making beer last longer. Then we can package it, either bottles, cans, or
kegs. This is the overall beer process. We're taking a grain, letting it start its germination,
stopping it so that we can use enzymes to convert carbohydrates into simple sugars.
Those simple sugars are then converted into ethanol, and then we finish that out by allowing
the fermentation with the yeast to not only create ethanol but also create carbon dioxide.
This is what we know of as beer.