Yeast And High Abv Beer: Double The Packets, Double The Fun?

When brewing high ABV beer, it is important to consider the amount of yeast to use. While some sources suggest that one packet of yeast is usually sufficient for a 5-gallon batch of beer, others recommend using two packets, especially for high-gravity beers. Using too little yeast can result in underpitching, which can affect the quality of the beer. On the other hand, overpitching can also have negative consequences, such as reducing ester production and resulting in thin or lacking body and mouthfeel. Ultimately, the optimal amount of yeast to use depends on various factors, including the specific yeast strain, beer style, and brewing practices. Brewers can use yeast calculators and consider yeast health, aeration, and pitching rates to determine the appropriate amount of yeast for their high ABV beer.

Yeast tolerance and alcohol capability

Yeast is a living, single-celled organism that can only reproduce and grow within certain conditions. One of these conditions is the presence of alcohol. Each yeast strain has a limit, known as its "alcohol tolerance", which indicates the level at which yeast cells enter dormancy and stop fermenting. This alcohol tolerance is usually expressed as a percentage of alcohol by volume (ABV).

Most beer yeasts fall into the 8-12% ABV range for alcohol tolerance, though some English ale yeasts can only tolerate up to 7% ABV, and some high-gravity Belgian and ale yeasts can tolerate up to 15% ABV. Wine yeasts generally have a higher alcohol tolerance, ranging from 14-18% ABV, and some specialty wine and champagne yeasts can reach as high as 21% ABV.

It's important to note that yeast alcohol tolerance is not a fixed number and can vary depending on several factors, including yeast strain, yeast health, available nutrients and sugars, and other factors. However, as a yeast approaches its alcohol tolerance level, fermentation will slow down considerably and will typically stop within a percent or two of the published tolerance level for most strains.

For example, if you're brewing a high-gravity beer with a low-tolerance yeast strain, fermentation may stop before the yeast has converted all the sugars, resulting in a very high finishing gravity and an overly sweet beer. On the other hand, some brewers take advantage of this by using a very high starting gravity with a known yeast, so that the yeast reaches its alcohol limit before all the sugars are consumed, leaving residual sweetness in the beer.

When selecting a yeast strain, brewers should consider the desired alcohol content of their beer and choose a yeast with an appropriate alcohol tolerance. Additionally, proper yeast handling, such as creating a healthy starter, ensuring adequate aeration, and maintaining optimal temperatures, can help improve the performance of the yeast and increase the chances of a successful fermentation, even when approaching the yeast's alcohol tolerance limit.

The impact of overpitching

Overpitching yeast is when you double or triple the necessary yeast count. This can cause the yeast to quickly consume all available oxygen and fermentable sugar. The yeast is so over-concentrated, proper fermentation is irreversibly altered.

• Luncheon meat flavour – Overpitching can cause the yeast to turn cannibalistic, eating itself and creating a luncheon meat flavour.
• Scouring acidity – Overpitching can lead to a souring acidity flavour.
• Goat-hide flavour – A goat-hide flavour is another potential off-flavour when overpitching ale yeast.
• Autolysis – Overpitching can cause autolysis, where the yeast cells rupture and disintegrate into the beer. This can make the beer permanently cloudy and add off-flavours.
• Low ester production – Overpitching can result in very low ester production, which may be desirable for some beer styles but can also lead to a lack of body and mouthfeel.
• Fast fermentation – Overpitching can cause very fast fermentation, which may be desirable in some cases but can also lead to a lack of body and mouthfeel.
• Thin body – Overpitching can result in a thin or lacking body and mouthfeel in the beer.
• Autolysis – Overpitching can lead to autolysis, which can cause yeasty flavours due to the lysing of cells.

It's important to note that the impact of overpitching can vary depending on the specific strain of yeast and the style of beer being brewed. For example, overpitching lager yeast may not have the same negative effects as overpitching ale yeast, as lager yeast ferments at lower temperatures and has a slower metabolic rate.

Yeast health and aeration

Yeast Health:

• Yeast Selection: Choose a yeast strain that can tolerate high alcohol levels and produce the desired flavour profile. Some yeasts may struggle above 10-12% ABV, so select a strain suitable for your target ABV.
• Pitching Rate: Ensure you pitch an adequate amount of healthy yeast. For high-gravity beers, you may need multiple yeast packets or a yeast starter to achieve the required cell count. Underpitching can lead to sluggish fermentation and undesirable flavours.
• Rehydration: Rehydrate dry yeast before pitching to maximise cell count and ensure yeast health.
• Age of Yeast: Consider the age of your yeast packet. Older yeast may require a higher pitch rate to ensure viability.

Aeration:

• Oxygenation: Aerate the wort adequately to provide yeast with the oxygen needed for growth and reproduction. Pure oxygen or air can be bubbled through the wort, with higher-gravity worts requiring longer aeration times.
• Nutrition: Provide sufficient nutrients for yeast health and growth. All-malt worts typically contain the necessary nutrients, but additional yeast nutrients may be required when using significant amounts of adjuncts or sugars.
• Temperature Control: Maintain recommended fermentation temperatures to prevent yeast from becoming dormant before completing fermentation. Higher temperatures may produce undesirable flavours, while cooler temperatures can slow or stop fermentation.

By focusing on yeast health and proper aeration, you can create an optimal environment for yeast to thrive and successfully ferment high-gravity beers.

Recipe design and fermentables

Recipe design and fermentable selection are crucial aspects of brewing high-ABV beers. Here are some key considerations for achieving success:

Yeast Selection:

Start by choosing the right yeast strain for high-ABV brewing. Not all yeast strains can handle high alcohol levels, so opt for yeast specifically designed for high-gravity fermentation, such as White Labs WLP099 (Super High Gravity Ale) yeast. Ensure you have a healthy yeast pitch rate and consider making a yeast starter to increase cell count and prevent stressed yeast, which can produce off-flavors.

Fermentable Selection:

To increase the ABV of your beer, you need to provide more fermentable sugars for your yeast to consume. There are several ways to achieve this:

• Increase Malt Extract: Adding more malt extract, either dry or liquid, will boost the specific gravity of your wort. This method can increase the body of the beer, result in a higher finishing gravity, and potentially decrease the perceived hop bitterness. It may also add a spicy flavor and aroma and increase alcohol warmth.
• Add Simple Sugars: Simple sugars like corn sugar, table sugar, honey, or brewer's crystals can effectively increase ABV. However, be cautious as too much simple sugar can lead to poor fermentation, decreased body, increased hop bitterness, and a spicy flavor profile.
• Use Adjuncts: Adjuncts such as unmalted grains, fruits, or other fermentable sources can contribute additional sugars for fermentation. This method allows for creative flavor profiles while boosting ABV.

Recipe Balance:

Increasing ABV will alter the balance of your beer's flavor, aroma, and texture. As you increase fermentables, consider adjusting other ingredients to maintain the desired balance. You may need to increase the amount of hops or other additives to counter the increased malt presence. Experimentation is key to finding the right balance for your high-ABV brew.

Fermentation Management:

High-ABV fermentations can be challenging, so proper fermentation management is crucial. Ensure your yeast has adequate nutrients and oxygenation. Consider adding yeast nutrients to provide the necessary vitamins and minerals for healthy yeast. Aerate your wort adequately before pitching yeast to provide sufficient oxygen for yeast growth and fermentation.

Additionally, consider step feeding your wort to the fermentation. Instead of adding all the wort at once, add it in stages as fermentation slows. This technique helps maintain a less stressful environment for the yeast by keeping the gravity relatively low throughout fermentation.

Finally, be patient during fermentation. High-ABV beers can take longer to ferment, and rushing the process can lead to off-flavors or incomplete fermentation. Allow the yeast to work at its own pace and ensure fermentation is complete before packaging your beer.

Feeding the yeast

When brewing high ABV beer, feeding the yeast is a crucial aspect to ensure a successful fermentation. Here are some detailed instructions and considerations for this process:

Yeast Requirements for High ABV Beer:

Firstly, it's important to understand that not all yeast strains are created equal when it comes to alcohol tolerance. Some yeast varieties, such as the Super High Gravity Ale Yeast, can ferment up to 25% ABV when used correctly. However, for most yeast, the limit is much lower, and additional steps need to be taken for high ABV brews.

Starting with a Healthy Pitch:

To start the fermentation process for a high ABV beer, it is recommended to begin with a healthy pitch of yeast. This means using a sufficient amount of yeast that is properly rehydrated and active. For beers with an ABV above 10%, it is crucial to have a robust and healthy pitch to ensure the yeast can withstand the higher alcohol levels.

Aeration and Pitching Rates:

Adequate aeration is essential when preparing for a high ABV fermentation. Oxygen is crucial for yeast growth and reproduction, and it helps the yeast build the necessary strength to tolerate the alcohol produced during fermentation. Additionally, proper pitching rates are critical. Underpitching can lead to sluggish fermentation, while overpitching may result in reduced yeast character and flavour.

Feeding Sugar Gradually:

To achieve an ABV higher than 25%, it is necessary to feed the yeast with sugar gradually throughout the fermentation process. This technique is often referred to as "feeding" the yeast. By slowly adding sugar, you can help the yeast build up its alcohol tolerance and avoid overwhelming it with high levels of alcohol or osmotic pressure. This process requires careful monitoring and control to ensure the yeast remains healthy and active.

Yeast Selection:

Not all yeast strains are suitable for high ABV beers. When selecting a yeast, it's important to consider its alcohol tolerance and the specific requirements of your brew. Some yeast strains may struggle above certain ABV thresholds, so choosing a strain that can handle the desired alcohol level is essential. Additionally, the yeast's flavour profile should complement the style of beer you are brewing.

Temperature Control:

Maintaining the optimal temperature range for your yeast is crucial during fermentation. Different yeast strains have specific temperature requirements, and deviating from these ranges can impact the flavour and fermentation process. For example, the Super High Gravity Ale Yeast from White Labs performs best at a temperature between 65°F and 68°F (18°C to 20°C).

In conclusion, feeding the yeast is a critical aspect of brewing high ABV beer. By following these instructions and considerations, you can create the optimal environment for your yeast to thrive and successfully ferment your high ABV brew. Remember that proper yeast management is an art and a science, and it may take some experimentation to perfect your high ABV beer-making skills.

Frequently asked questions