Some homebrewers have a certain style they love making, others love to experiment while a few wish to perfect a certain recipe. But then there are some who simply wish to make these most alcoholic. Alcoholic content is measured in Alcohol by Volume, or ABV for short. There are many ways to increase ABV but you have to be careful while doing it. Brewing is like a little chemistry experiment, you have to balance it right to make sure the process goes the best it possibly can.
One of the biggest factors is sugar, seeing as it is what we are going to be turning into alcohol. On the most basic of levels, sugars are the key limiting factor. If there is no sugar to convert to alcohol then it can’t happen. So what are our sources of sugar? Well the easiest source is the malt, without any additives this is where all your sugar will be coming from. So you might choose to use more malt or sugary adjuncts. Doing so will also add to the body of the beer, along with the aroma and flavours. Malt Extract is a powered form of malt that can be easily used to bulk up your homebrew. Often these won’t have much if any effect on the body and other aspects of your beer. So it is a really easy and clean way to increase your ABV.
But what about those additives? Basic table sugar can do the job. There are more interesting ingredients you could try like honey, maple syrup, brown sugar etc. You can add anything sugary you want to the beer really and many will impart their own flavours to the beer. However, this will often lead to a weaker body, drier taste and more bitter beer. That might be exactly what you want, in which case it is no problem. The bigger issue though is that you can over saturate the beer, which means all the chemical process we want to go on stop working. So while you can increase ABV this way, along with other effects, it is best to keep it to a minimum.
Yeast is of course the other key factor, its role in increasing ABV is a bit more complicated but needs to be understood. Brewer’s yeast comes in many different strains. We select yeast based not only on what type of beer is being made but what qualities are wanted. Part of this is ABV. Yeasts will generally have a hard limit of how much alcohol they can produce, many stop working at high concentrations. The limit for most 10-15%, but many stop well before that and others can go on a little longer. You will also find that as time goes on, the rate of alcohol production slows down. This can be from the yeast cells dying or from most of the substances needed being used up. Nutrients can be introduced to help the yeast live a bit longer, and more yeast can be added over time. Both of these need to be done very carefully, but many of the above problems still remain. While we can attempt to take yeast to its limit, at the end of the day the limit is where it stops.
Experimenting in homebrewing is a balancing act. Achieving what you want may often require losing out on other aspects. The better you get, the closer you can get to the beer you want.