Does Homebrew Beer Give You a Hangover? [All About Fusel Alcohols]


Many homebrewers report that they have gotten a bad headache or hangover after drinking their beer, even if they drank in moderation. Since we all want to love the beer we make at home, we need to find out why this happens so that we can prevent it!

Other than overconsumption, the most likely reason for getting a headache or hangover after drinking homebrew is the presence of fusel alcohols in the beer. These alcohols, sometimes called fusel oils in Europe, are a mixture of amyl alcohols commonly created as a by-product of fermentation. Proper homebrewing techniques can dramatically reduce the presence of fusel alcohols in beer.

If you have a fridge full of homebrew that gives you a headache there might be some hope in saving it, but it’s best to prevent letting fusels build up in your homebrew if you can help it. Let’s dive into some of the details of this question!

Why does my homebrew give me a headache?

Anyone that has done a fair amount of drinking has probably woken up the next morning with a splitting headache at one point or another. If it was a really wild night, you might have even visiting the toilet a few times as well! As for why these headaches and hangovers occur, the answer can get a little complicated.

On the one hand, you have basic overconsumption. If you drink a lot of alcohol, whether it is beer or something else, then your body is tasked with processing the alcohol and cleaning it out of your system. When a lot of alcohol is present, this is challenging in a number of ways. Since alcohol is a diuretic, it also causes your body to remove more fluid than normal, it can easily cause you to become dehydrated, if you aren’t careful, and suffer a major headache as a result.

As a result, most veteran drinkers eventually incorporate a system that forces them to drink water throughout a session of beer drinking.

On the other hand, and the topic of this article, is that homebrew beers can also cause a bad headache for drinkers even if they aren’t necessarily drinking too much and it all comes down to a pesky by-product of fermentation called fusel alcohols. The term refers to a certain group of ‘high alcohols’ that can be produced during fermentation and studies show that there is a clear link between these fusels and hangovers symptoms.

There are surely a few other reasons that beer could give you a hangover, but these are by-and-large the most common. Luckily, both of these problems can be fixed with a little self-control, preparation, and patience. Let’s dive into more detail about fusel alcohols and figure out whether or not we can salvage hangover-inducing homebrew and how to prevent it from happening in the next batch.

What is fusel alcohol in homebrew and how does it get there?

So I mentioned already that fusel alcohols are a common by-product of fermentation in homebrew. In fact, the word fusel itself is German for ‘bad liquor’ and comes from the long lines of German brewers that knew full well the issues they caused with their brewing. Fermentation is a complicated process and there are so many variables that it gets very difficult to tease out all of the minute details.

With that being said, we know that fusel alcohols are aliphatic (just means open-chain carbons) and aromatic alcohols and actually come from the breakdown of amino acids in protein rather than sugars during homebrew fermentation through a process known as the Ehrlich pathway. While the fusels are created quickly at the beginning of this pathway, they are reduced in the final step. Since the chemical changes and other activity that takes place through the Ehrlich pathway happens relatively slowly compared to the rest of the fermentation process, it can take quite a while for the fusel alcohols to clear up.

Still, there a few factors of the brewing process that can lead to more fusels being produced:

  • Type of yeast strain (ale strains typically produce more)
  • Higher fermentation temperatures
  • Stressed yeast (due to underpitching or other poor conditions)
  • High-gravity beers (due to the higher ethanol content)
  • Bottom yeasts
  • Stirred-batch or continuous fermentation setups
  • Recipes that lead to higher amino acid (such as leucine) levels in the wort

So, basically we know that fusel alcohols are completely normal, show up early, and take a while to go away. Now, let’s see what they do to the beer.

Does fusel alcohol cause an off-flavor in your beer?

The answer to this question is both yes and no.

We already know that fusel alcohols are a completely normal part of the fermentation process and, as such, a completely normal part of the flavor profile in many beers. With that being said, having too much fusel alcohol adds flavors that are generally considered bad in finished homebrew.

Fusel alcohols contribute an ‘alcoholic’ or ‘boozy’ taste in homebrew and can also add a warming sensation to the taste, aroma, and even inside your stomach. Beers with too much fusel alcohol in them might be referred to as ‘hot’ beers. Some can also add a hint of fruitiness.

With this in mind, we actually want to strive for the right balance of fusel alcohol in our homebrew so that we have the touch of warmth that we like to feel from beers, especially bigger beers, but don’t have to deal with the harmful headaches. That balance can be tricky, but let’s see what we can do to set ourselves up for success on brew day!

How to avoid fusel alcohols on your next brew

As average homebrewers, we don’t really ever know exactly what is happening behind the scenes in our beer. We know that ingredients, technique, and other variables are all extremely important when it comes to the final product, but it’s usually impossible to know anything for sure. That means we typically use generalizations and err on the side of caution when it comes to the brewing and fermentation process.

If we are trying to avoid fusel alcohols in our homebrew, then we generally want to do a few things right on brew day and during fermentation:

  • Bring your wort to a quick, rolling boil without a lid whenever possible
  • Use a yeast starter to ensure that you aren’t underpitching
  • Aerate the wort extremely well when adding the yeast to avoid stressing it
  • Ferment below 70 degrees Fahrenheit
  • Keep fermentation temperatures stable throughout
  • Keep beer in the primary longer
  • Allow your bottled beer to condition longer

This is a lot of info to keep in mind on brew day, but honestly, most of these are general best practices that you should be doing anyway!

How to remove fusel oils or alcohols from your beer

For those of you that already have beers sitting in the fridge that you’ve had hangovers or headaches with after drinking, there might be some hope for your situation. While the best way to handle fusel alcohols in your beer is to prevent them from getting there during the brewing process, what’s done is done.

As with most brewing issues, time can be a friend to the patient homebrewer. Anecdotally, many homebrewers have said that they were able to reduce the taste and aroma of fusel alcohol by letting their beer sit in the bottle for a longer period of time before drinking it. Unfortunately, results were mixed when it came to reducing the headaches from drinking the same beer.

How much longer? Way longer.

If your recipe generally calls for your beer to bottle condition for 6 weeks then maybe you will need several months. For bigger beers like Imperial Stouts, it might take even longer. Remember that fusel alcohols are a normal part of beer, but they operate at a slower frequency than some of the other chemical reactions of the fermentation process. This means they will take even longer to resolve naturally.

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