Fermentation Under Pressure: A New Era for Homebrewers

Fermentation under pressure, also known as pressure fermentation, has become a popular method among home brewers in recent years. While it may seem like a new technique, commercial breweries have been using this method for decades. Thanks to new technology and available equipment, this advanced brewing method is now within reach of home brewers.

What is Pressure Fermentation?

Pressure fermentation involves fermenting the wort in a closed container under a certain pressure. Examples of equipment for homebrewers include the Fermzilla Allrounder, Kegmenter, or a Cornelius keg with a serving lid and an adjustable pressure relief valve such as the Blowtie or Spundit.

Advantages of Pressure Fermentation

1. Cleaner Taste : Pressure fermentation reduces the production of esters and fusel alcohols, which gives a cleaner taste and aroma profile. The beer therefore requires less maturation time and is ready to drink faster.
2. Efficient Fermentation : The overpressure provides a quieter fermentation process without the need for temperature control, reducing the risk of unwanted flavors.
3. Natural Carbonation : The beer naturally absorbs CO2 during fermentation, resulting in a finished carbonated beverage.
4. Oxygen-Free Environment : A closed system from fermentation to bottling minimizes oxygen exposure, which is especially important for beer types like IPA and NEIPA.
5. Faster Fermentation : The process is faster and less dependent on temperature. For example, a lager can be fermented in 7-10 days at room temperature.
6. Preservation of Hop Aromas : Less of the volatile aromas from the hops disappear, resulting in a more aromatic beer.

Disadvantages of Pressure Fermentation

1. Loss of Yeast Character : Pressure fermentation can suppress the yeast's ability to contribute complex flavors. Therefore, beers such as Weissbier, Belgian beers, and some British beers should not be pressure fermented from day one.
2. Dry hopping : Dry hopping under pressure can be challenging, but there are solutions like the Hop Bong to make the process easier.
3. Yeast reuse : High pressure can weaken the vitality and ability of yeast to divide, which can make yeast reuse less effective.

How to Pressure Ferment?

Equipment needed:

• Fermentation tank for pressure (Fermzilla Allrounder, Fermzilla Conical, Kegmenter, Brewtools Unitank or Cornelius barrel)
• Adjustable pressure relief valve (Ball lock with Blowtie, Duotight Blowtie 2 Spunding valve)
• Equipment for closed transfer or direct serving from tank

Procedure:

1. Preparation : Brew the beer and chill it in the usual way.
2. Fermentation : Drain the wort into the fermentation tank and add the yeast. Use a pressure relief valve and adjust it to 0.7-1.0 bar (10-15 psi).
3. Dry hopping : When dry hopping, release the pressure temporarily, add the hops quickly, and add new CO2 to restore the pressure. Alternatively, use special equipment such as a Dry Hop Device to avoid oxidation.
4. Transfer : Once fermentation is complete, transfer the beer to kegs or serve it directly from the fermentation tank. Use a closed transfer kit to avoid oxygen exposure.
5. Carbonation : The beer will be partially carbonated after fermentation. Post-carbonate with added CO2 to reach the desired level.

Simple and Effective: Fermentation in Cornelius Barrels

For those who want a simple method, you can ferment directly in a Cornelius barrel:

1. Fill a clean barrel with wort and add the yeast .
2. Install a serving lid and a pressure relief valve .
3. Let it ferment for about a week at room temperature with counter pressure .
4. Place the keg in the refrigerator, connect CO2 for final carbonation adjustments, and serve the beer 1-2 days later .

Pressure fermentation represents an exciting opportunity for home brewers to improve the quality and efficiency of their brewing process. With the right equipment and a few simple adjustments, professional results can be achieved in the comfort of your own home kitchen. Cheers!