Why is it important to homebrew or use professional equipment to brew craft beer for commercial use? Because of the small batches and flexibility of home brewing, the brewer is free to make certain changes, additions, and manipulations to the fermentation process (such as adding sugar to increase alcohol production). The fermentation process of professional equipment cannot be adjusted.
Remember, sugar is the source of alcohol. No sugar, no fermentation, no alcohol. So, the more sugar, the better. To some extent, this is true. But two aspects of the choice of yeast play an important role here – sugar tolerance and alcohol tolerance. Alcohol tolerance is the percentage of ABV at which yeast die due to excess alcohol, and sugar tolerance is the percentage of Brix at which yeast die due to excess sugar. The high concentration of sugar acts as a desiccant and dehydrates and kills the yeast cells.
So, the best solution to adjust the sugar content of the wort during beer brewing is to increase the initial wort concentration (OG) instead of adding sugar to the wort.
As mentioned in the previous step, two aspects of the yeast will affect the fermentation process from the start – alcohol tolerance and sugar tolerance. When brewing low-alcohol beers, where there is only enough sugar in the wort to produce a 9% ABV beer, it is not necessary to use yeast tolerant to 18% ABV. But when brewing beer or spirits with high alcohol content, using yeast with low alcohol tolerance will affect the activity of yeast during fermentation, resulting in failure or insufficient fermentation.
The pH of the Wort
As with sugar tolerance and alcohol tolerance, each type of yeast has an optimal pH environment for effectiveness, although this is usually related to the ingredients. The pH value of the wort of beer before fermentation is usually 5.2-5.6, and during fermentation, the pH continues to drop. So check the cold wort pH before fermentation starts to make sure it doesn’t affect the fermentation process.
Enough Oxygen in the Fermenter
Yeast produces energy through its metabolism during the fermentation process through aerobic and anaerobic stages. In an aerobic environment, yeast respires and reproduces. This allows us to use small amounts of yeast in large batches. So, for beer with insufficient oxygen content, it is necessary to perform wort oxygenation before the fermentation process. But most beer fermentation is isolated from the air, meaning it occurs in closed fermenters. This allows the yeast to undergo fermentation after all the oxygen in the tank has been consumed, creating a carbon dioxide-rich environment.
In general, ales (18°C-22°C) are almost always fermented at higher temperatures than lagers (7°C-16°C).
In a sense, heat acts as a catalyst, causing the particles in the beer to become more active and move faster. The hotter the beer, the faster the yeast can consume the sugar and convert it into alcohol and CO2. But high temperatures can also create a number of problems.
Warmer temperatures cause yeast to produce more fusel alcohols, which are particularly strong alcohols that can give a beer a harsh taste. It’s often compared to cheap alcohol that overpowers the flavors of the beer’s key ingredients.
Warm yeast can also promote the production of more acetaldehyde. This compound is present in trace amounts as part of normal fermentation, but too much can lead to green apple flavors in beer.
Following the above steps in the planning and execution of beer fermentations will reduce the possibility of fermentation problems, as well as improve alcohol yields and flavor profiles.