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Brewing Better Beer – Fine-Tuning Fermentation

Fermentors in a row at Allagash brewing company

“Fermentation and civilization are inseparable.”

John Ciardi

Yeast is the reason we’re here right now. The reason why you’re reading this, the reason why we wrote this post (or wrote anything about Allagash at all). Fermentation is a yeast cell’s goal in life. Valiantly turning sugar into alcohol, carbonation, and tasty esters. What we’re going to talk about here is how we handle fermentation at the brewery, and how we coerce these wonderfully hungry organisms into making consistent, delicious beer.

First and foremost, our whole team needs to be on the same page. Communication, across the board, is actually one of our greatest assets when it comes to quality. It’s essential that our team knows: the right tank is scheduled, the yeast is fresh and ready, the proper cleaning has already occurred on the tank, and a litany of other items that need to be double checked before the wort is ready to start fermenting.

SIDENOTE: determining that the yeast is “fresh and ready” could take up a blog post (or book) of its own. Because of that, and the fact that most yeast preparation happens in our lab, we’ll save that topic for a later post. For now, however, it’s still important to know that before it ever meets (unfermented) beer, the yeast has been scrutinized for viability—or rather, it’s ability to create the type of beer we want it to. Then, and only then, will we pitch it.

Fermentor of Allagash White

Once we’ve combined the yeast and wort in a vessel, fermentation officially begins. After fermentation is complete—which, for different beers takes different amounts of time—the beer makes its way to a keg, bottle, or both.

The last two sentences contain a massive amount of quality control.

On the first day of fermentation, we’ll check the yeast’s cell count and the beer’s density, pH, and temperature. On the second day, we’ll check the cell count, density, and temperature. Then, every single day until the yeast is finished, we’ll check the density and temperature. And the “we” means two things. While a cellar person checks those numbers (and records them), they also send samples of beer to the lab to be double-checked and stored for later.

This checking goes down no matter what: weekends, holidays, you name it. On top of actual people recording measurements, much of our equipment also keeps a record. For example, our fermentors log their temperature constantly, so we can look back for fluctuations on any given day down to the second.

Sampling beer

Before and after fermentation, the tank is thoroughly cleaned, visually inspected, then sanitized. When we’re dealing with a wild yeast like Brettanomyces—not saccharomyces, or typical brewer’s yeast—we go to another level. The tank is cleaned, inspected, and sanitized per usual. Then, we switch out of every part that touches beer (minus the tank itself). This means rubber valves, zwickels (the sampling valve), gaskets, and more. The parts that we then switch back in are specific “wild” parts that we only use when fermenting beers with wild yeast. After the wild beer is fermented and ready for packaging, we clean the tank so thoroughly that our nickname for the process is “nuking” the tank. This involves an extremely thorough cleaning regimen, followed by the switching out of every part again, to ready the tank for traditional yeast.

the centrifuge at Allagash Brewing Company

After fermentation is complete, our beer heads to the centrifuge. This piece of equipment offers us tight control over the beer’s final appearance and mouthfeel. Allagash White would be the best example of this tool at work. White is brewed to have a hazy appearance that’s full of flavor and aroma thanks to yeast and undissolved proteins. Getting a consistent and appropriate level of haze is a delicate task—that our centrifuge is up to. The ‘fuge can measure turbidity—a beer’s haziness—and bring it to a specific level. Allagash White’s ability to hold its desired level of haze (rather than letting the particles sink to the bottom) is something we agonize over every day. This step is just one of the many ways we help all of our beers retain and maintain their signature characteristics from batch to batch to batch.

Also very cool to note: our centrifuge can save specific centrifuging regimens. So the regimen that we’ve dialed in for White will be different than Tripel, or Hoppy Table Beer, or Sixteen Counties and so on.

So much more could be said about all the tools in the fermentation process. But the main picture is this: no matter the tools and measurement devices we have at our disposal, it’s our team itself that ultimately controls the quality of our beer. Which is why we have processes in place for every step, to make sure that we’re all working together, in the same way, toward the goal of more delicious beer.

From here, we move to the packaging line where the beer you love meets the bottle (or keg, or can) you know.

a fermentor at Allagash Brewing Company

<– Read the previous blog in this series     Next blog coming soon… –>

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