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More on the "cold side" of brewing


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.