Sulfur has a strong scent resembling rotten eggs and is not a desired compound in any homebrew beer.
If your fermenting beer gives off an obvious sulfuric scent it’s a normal sign of fermentation with certain yeast strains, but it will be important to account for it because if sulfur is left unfiltered, the final beer will taste and smell bad.
When I first time brewed a wheat beer (hefeweizen) I discovered the unpleasant sulfuric scent and out of poor knowledge, I didn’t pay attention to it before it was too late. This cost me a decent batch of beer and since then I adapted the method whenever I brew with yeast that produces sulfur.
What produces sulfur in beer?
Bottom-fermenting yeast strains and even top-fermenting wheat yeast strains cause high production of sulfur as part of a normal yeast fermentation process.
Although other top-fermenting yeast strains also produce sulfur it’s often so minimal and neglectable.
If you are brewing lager, pilsner, wheat, and similar beers which use high sulfur-producing yeast strains, you must be careful or it could compromise your beer.
What can go wrong?
Sulfur has a strong, rotten-egg scent which is extremely unpleasant to humans as we associate it with rotten food and as such this evolutionary trait made us survive so far.
Moreover, when we taste food and drinks the tongue doesn’t play the only role in perceptiveness, but the nose plays an even bigger role.
If you smell the strong sulfur scent when drinking beer it means your whole experience will be ruined and it won’t taste nearly as good as it should.
By prematurely bottling or kegging it’s possible to trap the sulfur inside the beer and it will be too late to do anything about it. Thus, be patient and first remove the sulfur before bottling as this will be a critical factor for a successfully brewed beer.
How do you reduce sulfur in beer?
Add anti-sulfur fining agents
There are fining agents traditionally used in winemaking for removing sulfur and they also work with any other brew including beers.
These fining agents are based on copper as its shown that copper greatly neutralizes sulfur.
Fining agents work for removing the Volatile Sulfur Compounds responsible for that rotten egg smell we are talking about in this article, but also for DMS ( Dimethyl Sulfide) responsible for cooked corn and vegetables taste and phenols responsible for medicinal off-flavor.
These agents are an extra cost but they aren’t expensive and are a smart choice when brewing certain beer styles such as lagers, pilsners, wheat beers, and ciders or wines.
Let it sit out
It’s possible to let the sulfur evaporate from beer when the beer finished fermenting by letting it sit for a week or two!
This can be done in a primary or even better in a secondary fermenter as you’ll also get rid of annoying sediment at the same time.
This is the easiest method available to homebrewers as it doesn’t cost anything and you just have to forget about the beer for another week or so until it’s ready.
You can also cold crash beer to accelerate the process by simultaneously cleaning the beer from sediment.
Purge it with Co2
It’s possible to purge beer with Co2 and remove the sulfur presence but it requires extra equipment like a keg and Co2.
If you have this equipment by hand, you can accelerate the process of natural sulfur reduction otherwise achieved by letting the beer sit out in the fermenter.
You can also let the beer sit for some time and then by the end purge it to get rid of the last tracks of sulfur. If there is plenty of sulfur in beer, it will take more than a few attempts to get rid of it by purging it with Co2, so bear that in mind.
Conclusion
I learned from mistakes done in the past and now I always let the beer with an obvious sulfur odor sit out in the fermenter for extra time before bottling.
I rarely brew lagers and wheat beers as my beer of preference are ales, but when I do I try to do it with the right technique.
Throughout my brewing journey, I realized that brewing can be more complex than it seems at first, but It can also be very simple and enjoyable when you get prepared in advance.
I am not going to lie, my hefeweizen is not nearly as good as it should be even when I don’t make rookie mistakes of not filtering sulfur out before bottling but with time I hope I’ll get there and then share some recipes I can finally vouch for!
And for the end, if you regularly brew these beer styles which produce plenty of sulfur during fermentation, try out those fining agents, after all, they are a part of the standard practices in many breweries across the world.