If a home brewer just wants a quick beer and doesn’t care what the finished product really tastes like, they can throw all their ingredients in a plastic bucket and forget about them. Otherwise, the home brewer needs to pay attention to all the same things the pros do. That includes maintaining the right pressure and temperature. Pressure and temperature are critical to the pros, especially those who practice unitank brewing.
Temperature and pressure are important because they affect carbonation. Why does carbonation matter? Because it influences two things: a beer’s head and how the beer feels in the mouth when one takes a drink. The greater the carbonation, the greater the effect of both will be.
Strangely enough, temperature and pressure have inverse effects on carbonation. So getting the right balance is key to proper beer carbonation. In some commercial breweries, beer is put into separate finishing tanks for carbonation. In other cases, breweries address carbonation in-line while bottling. Still other breweries practicing a unitank brewing approach carbonating in the same tank where fermentation takes place.
More About the Unitank
History suggests the first commercial unitank was developed in the 1920s. It was invented by a man named Leopold Nathan, who patented tank designs in 1908 and 1927. The Rainier Brewing Company introduced its own twist on Nathan’s tank in the late 1960s. Their tank eventually went on to become the modern unitank.
Houston’s CedarStone Industry says that unitank brewing is fairly common in American commercial breweries. It has its advantages:
- A single tank from start to finish
- Less cleaning and sanitizing required
- More control over carbonation and gassing
- Easier dry hopping
- Beer can go right from tank to bottle.
Unitanks are design with extra head space. This is what makes dry hopping so easy. But it also allows for carbonating without having to transfer to a separate tank. Although some breweries prefer separate carbonation, a unitank has enough head space to accommodate carbonation in place.
Once again though, the trick is managing temperature and pressure. And imbalance can create an overly carbonated beer that doesn’t sit right in the mouth. But too little carbonation can make a beer taste flat and uninteresting. To manage things properly, commercial breweries tend to draw a correlation between head space and carbonation levels.
In other words, they increase head space pressure while keeping temperature constant. This increases carbonation by effectively forcing the beer to absorb carbon dioxide from the head space.
Built for Carbonation
CedarStoneIndustry says that while some unitanks are purposely built with carbonation in mind, others are not. One that is makes carbonation fairly easy. In fact, it takes most of the guess work out of it. A brewer’s biggest concern is determining the right amount of carbonation for accomplishing the desired flavor.
That being the case, it is probably not necessary for a home brewer or craft operation to obsess over exact pressure and temperature calculations. A general ballpark is good enough in most cases. Then it is a matter of watching things and testing. You test a little here and a little more there until the amount of carbonation satisfies your taste profile.
Maintaining temperature and pressure during the final stages of unitank brewing is all about achieving the desired level of carbonation. It may seem like rocket science, but it’s not. Unless you are running a corporate brewery that requires every bottle or can taste identical to every other, a little variation in carbonation isn’t a bad thing. So if your pressure or temperature is off slightly from one batch to the next, no big deal.