By Chris White
President, White Labs
At the Craft Beer Conference in Austin, Texas,
earlier this year, I gave a talk called "Hot vs. Cold." I discussed the
differences between the hot and cold side of brewing, and made the case
that the cold side (i.e. fermentation) is often the most neglected yet
the most important side of brewing.
Each phase requires high skills and expert techniques
to achieve optimal results. However, as important as the hot side of
brewing is, many of the issues that come up on that side of the process
can be corrected or alleviated through cold side manipulation. The cold
side is where beer becomes beer. And this is why brewers should put more
knowledge, efforts and resources into this phase.
This does not always happen in modern breweries,
however. Frankly, the cold side is just not as "sexy." Breweries spend
gobs of money on copper equipment for the hot side, in part because it
shows well to customers but also because of tradition. And often, after
these great initial expenditures, little money is left for the
production process and many corners are cut. The beer suffers
tremendously, and in some cases, so do the businesses.
The hot side involves the combination of two very
important ingredients, hops and malt, and these steps are very
important. The cold side, on the other hand, involves one ingredient,
yeast, but many key factors, including: yeast strain selection, yeast
growth, oxygen content, esters, potential contamination, and yeast
health. Mastery of all these cold side factors is critical to the
success of your brewing process.
A detailed description of all these factors would
take up an entire book, but for now we can talk about why the cold side
is so important. We handle many brewery related questions. Brewers often
believe that everything that happens after the cooking process is deemed
to be caused by, rightly or wrongly, fermentation. If brewers do not
realize that fermentation is the main element of brewing, they certainly
understand it on a subconscious level, as we are the first people they
turn to for answers as to what happened or might happen in the future
with their beer.
It is an interesting occupation in many ways. In one
respect, we are akin to others in the food industry, making an
ingredient that is used in some other product with some other name.
However, we also need to have the knowledge of someone in the high-tech
industry. To answer the questions that arise daily requires years of
knowledge and practical experience, particularly because this industry
has such a wide variety of practitioners, from entry-level folks to
those with years of experience.
Since beer begins and ends with the fermentation
process, thatís what I will concentrate on in the following.
As a brewer, are you a doctor or a coach? A doctor
would seek to find the problem with the yeast and fix it. This cannot be
done, however, with finicky single cell organisms that sometimes act as
if they have a mind of their own. Or are you a coach, who when he or she
finds a problem with a player replaces them with someone fresh and
energetic? Yes, brewers are coaches. The best way to avoid fermentation
trouble is to learn when you need to send in the second team (i.e. order
a new batch of yeast or alter the process). Insisting on doing the same
thing every time is not the right approach! You want to be open to new
procedures and change your practices if necessary, such as when
confronting seasonal issues.
If the yeast side is so important, what can we do to
make it better? We can look at them under a microscope, but the darn
critters are all small circles. They donít talk to us.
Or do they? Yes they do, in a manner of speaking. We
can measure their % attenuation, and if we know the characteristics of
the yeast, we should know this as well. We can track their rate to
completing fermentation, which is essential. We can follow their
flocculation. We can learn more through mutation plates.
Yes, indeed, yeast do speak to us in a way. One way
they talk to us is through smell. Yes, smell. You must get your nose in
there. To do so, get some of the yeast out of the tank, even if you are
not reusing it. The amount of times you will want to smell the yeast
vary depending on the strain and your equipment, i.e. your tanks. Get to
know your yeast!
Other factors of importance on the cold side:
- You must use consistent pitching rates. There are
several options to consistently measure the pitching rate: by cell
count, by weight, or by volume.
- Pay special attention to the yeast strain you
select, as each has a distinct personality.
- Consider performing trial fermentations as an
effective tool for controlling and predicting fermentations.
By learning to perfect the cold side, you will make more consistent
and better tasting beer than ever before.