Whether the brewer uses a cheap plastic brewing bucket, or a state-of-the-art stainless-steel temperature controlled conical fermenter, one key factor to producing quality beer is the ability to control fermentation temperatures, investing in a cheap fridge, with a heat source and temperature controller such as an Inkbird temperature controller (Source 10.19) will greatly improve the quality of beer for the home brewer of any level of experience. Each yeast will have an optimum temperature range, that can be raised or lowered to contribute different esters during fermentation that will attribute to the overall flavour and aroma of the finished beer.
One factor to consider, is the risk of unwanted pathogens or bacteria growing in the beer, all equipment that will come into contact with the beer throughout any of the processes should be thoroughly washed and sanitised prior to brewing. This includes equipment such as transfer hoses, fermenters, scissors used to open yeast and/or hop packets, hop bags/strainers used for dry hopping, and any final packaging. Whilst it is extremely rare (approx. 1 (+/-) case per year in Australia, 110 (+/-) cases per year in USA, 80 (+/-) cases per year in Europe), Clostridium Botulinum is one pathogen that brewers must take steps to reduce the risk of, as beer wort is an ideal place for this pathogen to flourish. Beer wort has a high protein content and a pH permissive to the growth of botulism (>5.0). It is unclear whether hops inhibit growth of botulism, although “inhibition has been observed” with highly purified extracts. Adjusting the pH of the wort soon after the hot side processes have finished is required to ensure adequate food safety guidelines are followed.
The good news for conventional beer brewers is that normal brewing practices will prevent botulism from growing. The oxygen levels achieved by normal oxygenation processes are inhibitory to growth, while the acidification during fermentation will suppress botulism long before it produces toxin. In other words, if the brewer quickly chills the beer, oxygenate well, and immediately pitch a good dose of yeast, the risk is essentially zero (Source 10.23). It is generally accepted that in Clostridium botulinum, both growth and toxin formation are completely inhibited at pH values below 4.6. This critical pH value has been confirmed by many investigators using food as substrate or culture media (Source 10.24).
With low and no alcohol brewing, the same drop in pH during fermentation is not observed due to the low rate of activity from the yeast and will lead to the beer having too high of a pH, making it an ideal substrate for contamination. Manual intervention to lower the pH to 4.6 or below is required to ensure a “food-safe” environment. The brewer must take steps to prevent the growth, the addition of lactic acid, phosphoric acid, or citric acid can acidify the wort to a pH at or below 4.6 prior to pitching the yeast to ensure a food safe environment.
Due to low rate of activity from the yeast, a krausen will often not be visible during active fermentation and may appear to have no activity from the yeast. This is in fact not the case, as the yeast will have undoubtably consumed the very little amount of sugars available very quickly. This can be referred to as a “phantom fermentation” and the brewer should avoid adding any extra yeast to the wort. Simply draw off a sample of the wort and check the specific gravity to track fermentation.