Does Fermenting Beer Longer Make It Stronger? (Plus Beer Style Guide)

Most homebrewers understand that more sugar in their recipe leads to a higher alcohol beer, but many wonder if fermenting their beer longer will make it stronger.

Fermenting beer for a longer period of time will not in and of itself make beer stronger or lead to a higher Alcohol By Volume (ABV) of the finished product. Once the fermentable sugar in the wort has been converted to alcohol and other byproducts, the yeast will shut down and begin to die off.

Although longer fermentation doesn’t lead to stronger beer, there are steps you can take to boost your ABV. Read on to learn more about the fermentation process, how to measure your ABV, and concrete tips for making your homebrew beer stronger.

Will Fermenting Beer Longer Make it Stronger (more alcohol)?

Whether you’re striving for a boozy sipper, a low-gravity porch pounder, or something in between, hitting your target alcohol-by-volume (ABV) can feel uncertain. Where does the alcohol in beer come from? And what should your target ABV be anyway?

Longer fermentation won’t make your beer stronger because any beer recipe has a finite amount of sugar in it. When you create mash by adding your malt to hot water, you’re activating enzymes in the malt, which convert starch to sugar. 

The resulting liquid, called “wort,” is the ideal environment for fermentation because of its high sugar content. Put simply- sugars are yeast food. By adding (or “pitching”) yeast to your wort, you begin the fermentation process. Over time, the yeast eats the sugar, emits a bit of CO2 flatulence, and, you guessed it, releases alcohol. Thank you, yeast!

Like any good smorgasbord, the fermentation process doesn’t happen all at once. It takes time in a temperature controlled environment for the yeast to eat up all those yummy sugars and produce the alcohol and CO2 so crucial to your finished product. Generally, the more sugar in your recipe, the more time it will take the yeast to consume them.

Can you ferment homebrew beer too long?

Yes, for most beer styles, you can run the risk of off-flavors or even ruining your entire batch by letting it ferment for too long. Please take a deep breath and read on. Your beer won’t over-ferment in the time it takes to read this article!

For a while, after pitching your yeast, they float around in your wort, slowly chomping up sugars and releasing CO2 and alcohol. But after some time, as most of your sugars are consumed and your yeast has done their thing, they begin what’s called flocculation. This refers to the time when your yeast starts collecting together at the bottom of your fermenter, or in some cases, floating to the top. You’ll know flocculation is occurring because the bubbles in your airlock will drastically reduce in frequency. Think of it as the end of popping a bag of microwave popcorn.

Much like your favorite movie snack, it’s possible to overdo it. For popcorn, this means burnt kernels. For yeast, this can mean (gulp) cannibalization.

That’s right, as sugar supplies run low, your yeast will start to die off and, in some cases, potentially even eat their brothers and sisters. Dead yeast and other gunk will start to accumulate at the bottom of your fermenter. Homebrewers typically call this “trub.” Though trub is a natural byproduct of fermentation, the more dead yeast in your brew, the more off-flavors you’ll detect. In extreme cases, you may even be overcome by an aroma of burning rubber. 

This is why longer fermentation is not the way to higher ABV. Keep an eye on your airlock and bottle your beer promptly! A general rule of thumb among homebrewers is never to leave a batch in a single fermenter for longer than four weeks. Most recipes will call for bottling or kegging well before that point.

What is Secondary Fermentation?

For beginning homebrewers, simply getting through a few primary fermentations may feel like a feat. However, secondary fermentation can be a great way to up your homebrew game and draw even more complexity out of your homebrew.

Secondary fermentation refers to the process of moving your fully fermented beer to a secondary vessel, typically a glass carboy, for an additional few weeks. Fans of secondary fermentation praise its ability to create clearer beers with fewer chances of off-flavors since the trub is filtered from your beer during the transfer process. 

The downside here is more time to wait before you can bottle and drink your homebrew. Also, be careful transferring your brew, as anytime you expose your beer to oxygen can lead to undesirable stale flavors or even ruin your batch. Don’t expose your homebrew to oxygen for any longer than you have to. 

Though it won’t make your beer stronger, secondary fermentation can be a simple way to enhance the quality of your homebrew with the right care.

Measuring Your ABV

ABV is measured by comparing the amount of sugars in your wort with the amount of sugars in your finished product. The difference implies the quantity of sugars that were turned into alcohol by the yeast. More missing sugars = higher ABV!

To do this, all you’ll need is a hydrometer and the formula below (or an online ABV calculator)

1. Measure Your Original Gravity (OG). Float the hydrometer in your wort before pitching your yeast and record the number. Pro-tip: save it in your phone or a dedicated brewing journal.
2. Measure Your Final Gravity (FG). Float the hydrometer in your finished beer and record the number.
3. (OG – FG) x 131.25 = ABV. For example, if your OG was 1.05 and your FG is 1.01 your ABV would be 5.25% because (1.05 – 1.01) x 131.25 = 5.25

You can measure your ABV along the way throughout the fermentation process, though be sure to keep your hydrometer sanitized to avoid contaminating and introducing undesirable flavors into your brew.

How do you make homebrew beer stronger?

Read on for a few tried and true methods for increasing the alcohol content of your homebrew.

Add corn sugar to your homebrew recipe

You may bristle at the idea of adding “corn” to your recipe but fear not. Corn sugar does not carry any flavors or mouthfeel of corn itself. It’s a simple sugar like table sugar but ferments out more cleanly than the sugar you put in your morning coffee. Because of this, corn sugar is a common ingredient for homebrewers and professional brewhouses alike.

Some recipes may already call for the addition of corn sugar, but you can also add it early in the fermentation process to those that don’t. Adding corn sugar to your finished brew can be a quick and dirty way to reinvigorate an underdeveloped brew or make a weaker beer style stronger.

When determining how much corn sugar to add, a good rule of thumb for a five-gallon batch is to add one pound of corn sugar for every one percent ABV you wish to add. Bear in mind that adding additional sugar to your brew can often affect the body, dryness, and of course, sweetness of your finished product. The more sugar you add, the thinner, dryer, and sweeter your beer will become, so proceed cautiously!

Add malt extract, brown sugar, or honey to your homebrew

In addition to corn sugar, you can add just about any other type of sugar under the sun: malt extract, brown sugar, and even honey. These sugars are much more likely to affect the flavor of your beer, so for the purposes of strictly increasing your ABV, corn sugar is your best bet.

Remember that alcohol kills yeast, so you may also want to add extra yeast when adding extra sugar. Not all yeast is created equal so be sure to choose a brewer’s yeast that can stand up to the alcohol content of your particular recipe. 

Choose a homebrew beer recipe with more alcohol

Don’t overthink it, start with a high-gravity recipe and get a high-gravity brew. Any homebrew recipe worth its salt will come with an expected ABV range for you to target. Here are a few beer styles that traditionally boast the highest alcohol content:

Barleywine – both American Barleywine and English Barleywine recipes can often reach ABVs of 12% or more. All barleywines have incredible flavor complexity due to the many sugars and malts necessary to reach those strength levels. American Barleywine is usually hoppier than its English brethren, so choose a style based on your tastes.

Imperial Stout – if a strong brew with toasted malts and a syrupy body sounds like your thing, look no further than the Imperial Stout. Commonly called “Russian imperial Stout,” due to its origins being shipped from England to Russia in the late 18th century, you can typically count on an ABV of 9%. This is one of the darkest beer styles, and many homebrewers find them to be the perfect beer to brew in the fall and bottle condition for enjoying when it starts to get chilly.

Double IPA – while traditional India Pale Ale (IPA) generally clocks in at 6-7% ABV, the Double IPA (DIPA) should usually come out between 7 and 9%. DIPAs double the amount of hops in the already-hoppy IPA, and additional malts and sugars are added to balance the natural bitterness of all those hops. That added sugar also leads to a stronger brew.

What is the world’s strongest beer?

Though the sky’s the limit when it comes to experimenting with ABV, at a certain point, you do meet the law of diminishing returns. Anything over 15% is going to have a very spirit-forward flavor profile and warming sensation that will start reminding you of hard liquor.

The world’s strongest beer at the time of publishing is the UK’s Brewmeister Snake Venom, clocking in at an absolutely insane 67% ABV. Drinker beware!