High gravity brewing is an advanced brewing technique that can be notoriously difficult. A high gravity beer is typically defined as one with an original gravity (OG) of over 1.075.
The term “high gravity brewing” may be confusing for some home brewers when searching online. The term is also used to describe how commercial breweries brew and ferment a high gravity beer, and then dilute it just before packaging.
Here is a list of problems you may encounter when high gravity brewing, along with their solutions:
1. Lower efficiency:
Solution: Take into account the lower efficiency in your brewing software when designing your recipe. If you normally achieve 75% efficiency, expect around 50-60% when high gravity brewing.
2. Lower hop utilization:
Solution: Trust that your brewing software will adjust the hop utilization to compensate for the higher gravity in your recipe. There are formulas available for adjusting hop utilization in high gravity brewing. Adding malt extract (DME or LME) at the end of the boil can also improve hop utilization at lower gravity.
3. Struggling yeast:
Solution: Choose an alcohol tolerant yeast strain and create a large yeast starter. Ensure proper aeration, preferably with pure oxygen, and add yeast nutrient such as Servomyces to increase chances of full attenuation. Instead of adding malt extract at the end of the boil, consider adding simple sugars during fermentation along with additional oxygen and nutrients to reduce yeast stress.
This process is similar to chaptalization in winemaking, where sugar is added not to increase alcohol content, but to help yeast adapt to increased osmotic pressures.
4. Fusel alcohols:
Solution: Start fermentation in the mid 60’s (64-66°F/18-19°C) and monitor gravity frequently. Temperature control during fermentation is crucial for high gravity brewing. Fermenting at cooler temperatures may take longer, but it leads to better alcohol integration, reduced fusel alcohols, and balanced flavors.
5. Stuck fermentation:
Solution: If you’ve ensured good yeast health, you may need to add more yeast to complete fermentation or consider adding Brettanomyces as a last resort. Champagne yeast is a good choice for stuck fermentations. Try moving the fermenter to a warmer location, agitate the yeast, and be patient.
6. Green flavors:
Solution: High gravity beers may exhibit green flavors when young. Aging your beer for an extended period, even up to a couple of years, can help mellow and condition those flavors. However, keep in mind that hops evolve with time. American Barleywines, for example, are often expected to taste like IPAs initially, but with more malt character and residual sweetness. Taste your beer periodically during conditioning to determine its peak readiness.
7. Difficulty in reproducing the beer:
Solution: Consistency is challenging even with regular homebrew recipes. Take detailed notes throughout the brewing process, fermentation, conditioning, and aging. Pay attention to gravity readings, fermentation rates, nutrient and sugar additions, and annotate all variables involved at each stage. If you have an award-winning beer, follow your notes precisely when rebrewing. The fermentation process remains the largest variable.
Additionally, note that the quality of judging feedback can vary widely. You might need to enter your high gravity beer in multiple competitions to gather a consensus on its strengths and weaknesses before making adjustments to your recipe.
8. Creating balance in a high gravity beer:
Solution: It is recommended to start with an established recipe, preferably one that has won awards. Otherwise, experimentation will be necessary.
High gravity brewing can be expensive due to the larger amounts of ingredients used, including grains, hops, and malt extracts if chosen.
These big beers are meant to be enjoyed slowly. Don’t expect to finish a keg of 12% ABV American Barleywine quickly. On the bright side, you can bottle and cellar age these beers for many years, enjoying vertical tastings over an extended period of time.