Pressure fermentation is a brewing technique that has gained popularity among professional brewers in recent years. The idea is to create hydrostatic pressure on the yeast during the fermentation process, which can lead to a number of benefits, such as suppressing yeast esters and slowing fermentation.
This technique is particularly effective for lagers, but can also be used for certain ales, such as hoppy beers. In this video, we will explore the benefits of this type of fermentation, the equipment needed, and the techniques involved in using this method.
Benefits of Pressure Fermentation
The primary benefit is the suppression of yeast esters. Pressure tends to reduce the formation of esters, which can lead to a cleaner and crisper taste in the final product. This is particularly important for lagers, where the goal of cold fermentation is to suppress esters. Additionally, pressure fermentation can slow down the fermentation process, which can help ensure that the yeast has enough time to fully consume all of the available sugars in the wort.
Another benefit is the allowance for slightly higher fermentation temperatures. Most pro-breweries can ferment at higher temperatures than the average home brewer, thanks to the ester suppression power of hydrostatic pressure. You can compensate for the slowness of the fermentation process by fermenting at warmer temperatures.
It’s important not to go higher than 5-10°F over your normal fermentation temperature. This will help ensure that the yeast doesn’t become stressed and that the fermentation process doesn’t become too fast.
To perform pressure fermentation, you will need a pressure-ready fermentor, such as a unitank or corny keg. These can be relatively inexpensive and easy to obtain. You will also need a spending valve, which can be added to a keg for ease of use.
Techniques for Pressure Fermentation
The main technique to follow involves applying 5-15 PSI of pressure at the start or towards the end of the fermentation process. Lagers are the best candidates for early pressure fermentation, as they tend to benefit from ester suppression. Additionally, most lager yeasts seem more resistant to the negative impacts of pressure fermentation than most ale yeasts.
For the most part, ales should have a good amount of ester production so they may not make sense for this type of fermentation. However, there are a few areas where using a late pressure ferment can be useful for ales. In hoppy beers, a bit of pressure may help retain some of the volatile aroma compounds in the beer.
Using late pressure retention can also be used to speed up carbonation. Applying pressure after the first 48 hours and holding it allows some ester formation to happen early during the yeast growth phase, but you can retain some of that pressure to carbonate the beer as it finishes.
Lastly, Fermenting under pressure also lends itself to being a closed system, especially if you are fermenting in a corny keg. Through the use of a jumper, you can transfer your beer from ferment keg to serving keg with little to no e oxygen ingression. is a positive
It’s important to note that pressure fermentation is not a universal solution and may not work for all styles or yeasts. Experimentation is necessary to determine the ideal pressure setting, which is likely strain dependent. With Kveik strains available and super clean W34/70, in some ways, this seems like a solution in search of a problem. However, for those looking to experiment with their brewing techniques, pressure fermentation can be an interesting and effective method to explore.